https://github.com/absaoss/cobrix
A COBOL parser and Mainframe/EBCDIC data source for Apache Spark
https://github.com/absaoss/cobrix
cobol cobol-parser copybook ebcdic etl mainframe scalable spark
Last synced: 3 months ago
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A COBOL parser and Mainframe/EBCDIC data source for Apache Spark
- Host: GitHub
- URL: https://github.com/absaoss/cobrix
- Owner: AbsaOSS
- License: apache-2.0
- Created: 2018-07-23T13:08:07.000Z (almost 8 years ago)
- Default Branch: master
- Last Pushed: 2025-09-29T08:40:48.000Z (8 months ago)
- Last Synced: 2025-09-29T10:23:37.305Z (8 months ago)
- Topics: cobol, cobol-parser, copybook, ebcdic, etl, mainframe, scalable, spark
- Language: Scala
- Homepage:
- Size: 4.78 MB
- Stars: 153
- Watchers: 23
- Forks: 84
- Open Issues: 105
-
Metadata Files:
- Readme: README.md
- License: LICENSE
- Codeowners: .github/CODEOWNERS
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README
# Cobrix - COBOL Data Source for Apache Spark
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[](https://mvnrepository.com/artifact/za.co.absa.cobrix/cobol-parser)
[](https://mvnrepository.com/artifact/za.co.absa.cobrix/spark-cobol)
Pain free Spark/Cobol files integration.
Seamlessly query your COBOL/EBCDIC binary files as Spark Dataframes and streams.
Add mainframe as a source to your data engineering strategy.
## Motivation
Among the motivations for this project, it is possible to highlight:
- Lack of expertise in the Cobol ecosystem, which makes it hard to integrate mainframes into data engineering strategies.
- Lack of support from the open-source community to initiatives in this field.
- The overwhelming majority (if not all) of tools to cope with this domain are proprietary.
- Several institutions struggle daily to maintain their legacy mainframes, which prevents them from evolving to more modern approaches to data management.
- Mainframe data can only take part in data science activities through very expensive investments.
## Features
- Supports primitive types (although some are "Cobol compiler specific").
- Supports REDEFINES, OCCURS and DEPENDING ON fields (e.g. unchecked unions and variable-size arrays).
- Supports nested structures and arrays.
- Supports Hadoop (HDFS, S3, ...) as well as local file system.
- The COBOL copybooks parser doesn't have a Spark dependency and can be reused for integrating into other data processing engines.
- Supports reading files compressed in Hadoop-compatible way (gzip, bzip2, etc), but with limited parallelism.
Uncompressed files are preferred for performance.
## Videos
We have presented Cobrix at DataWorks Summit 2019 and Spark Summit 2019 conferences. The screencasts are available here:
DataWorks Summit 2019 (General Cobrix workflow for hierarchical databases): https://www.youtube.com/watch?v=o_up7X3ZL24
Spark Summit 2019 (More detailed overview of performance optimizations): https://www.youtube.com/watch?v=BOBIdGf3Tm0
## Requirements
| spark-cobol | Spark |
|-------------|---------|
| 0.x | 2.2+ |
| 1.x | 2.2+ |
| 2.x | 2.4.3+ |
| 2.6.x+ | 3.2.0+ |
## Linking
You can link against this library in your program at the following coordinates:
Scala 2.11Scala 2.12Scala 2.13
groupId: za.co.absa.cobrix
artifactId: spark-cobol_2.11
version: 2.9.8
groupId: za.co.absa.cobrix
artifactId: spark-cobol_2.12
version: 2.9.8
groupId: za.co.absa.cobrix
artifactId: spark-cobol_2.13
version: 2.9.8
## Using with Spark shell
This package can be added to Spark using the `--packages` command line option. For example, to include it when starting the spark shell:
### Spark compiled with Scala 2.11
```
$SPARK_HOME/bin/spark-shell --packages za.co.absa.cobrix:spark-cobol_2.11:2.9.8
```
### Spark compiled with Scala 2.12
```
$SPARK_HOME/bin/spark-shell --packages za.co.absa.cobrix:spark-cobol_2.12:2.9.8
```
### Spark compiled with Scala 2.13
```
$SPARK_HOME/bin/spark-shell --packages za.co.absa.cobrix:spark-cobol_2.13:2.9.8
```
## Usage
## Quick start
This repository contains several standalone example applications in `examples/spark-cobol-app` directory.
It is a Maven project that contains several examples:
* `SparkTypesApp` is an example of a very simple mainframe file processing.
It is a fixed record length raw data file with a corresponding copybook. The copybook
contains examples of various numeric data types Cobrix supports.
* `SparkCobolApp` is an example of a Spark Job for handling multisegment variable record
length mainframe files.
* `SparkCodecApp` is an example usage of a custom record header parser. This application reads a variable
record length file having non-standard RDW headers. In this example RDH header is 5 bytes instead of 4
* `SparkCobolHierarchical` is an example processing of an EBCDIC multisegment file extracted from a hierarchical database.
The example project can be used as a template for creating Spark Application. Refer to README.md
of that project for the detailed guide how to run the examples locally and on a cluster.
When running `mvn clean package` in `examples/spark-cobol-app` an uber jar will be created. It can be used to run
jobs via `spark-submit` or `spark-shell`.
## How to generate Code coverage report
```sbt
sbt ++{scala_version} jacoco
```
Code coverage will be generated on path:
```
{project-root}/cobrix/{module}/target/scala-{scala_version}/jacoco/report/html
```
### Reading Cobol binary files from Hadoop/local and querying them
1. Create a Spark ```SQLContext```
2. Start a ```sqlContext.read``` operation specifying ```za.co.absa.cobrix.spark.cobol.source``` as the format
3. Inform the path to the copybook describing the files through ```... .option("copybook", "path_to_copybook_file")```.
- By default the copybook is expected to be in the default Hadoop filesystem (HDFS, S3, etc).
- You can specify that a copybook is located in the local file system by adding `file://` prefix.
- For example, you can specify a local file like this `.option("copybook", "file:///home/user/data/copybook.cpy")`.
- Alternatively, instead of providing a path to a copybook file you can provide the contents of the copybook itself by using `.option("copybook_contents", "...copybook contents...")`.
- You can store the copybook in the JAR itself at resources section in this case use `jar://` prefix, e.g.: `.option("copybook", "jar:///copybooks/copybook.cpy")`.
4. Inform the path to the Hadoop directory containing the files: ```... .load("s3a://path_to_directory_containing_the_binary_files")```
5. Inform the query you would like to run on the Cobol Dataframe
Below is an example whose full version can be found at ```za.co.absa.cobrix.spark.cobol.examples.SampleApp``` and ```za.co.absa.cobrix.spark.cobol.examples.CobolSparkExample```
```scala
val sparkBuilder = SparkSession.builder().appName("Example")
val spark = sparkBuilder
.getOrCreate()
val cobolDataframe = spark
.read
.format("cobol")
.option("copybook", "data/test1_copybook.cob")
.load("data/test2_data")
cobolDataframe
.filter("RECORD.ID % 2 = 0") // filter the even values of the nested field 'RECORD_LENGTH'
.take(10)
.foreach(v => println(v))
```
The full example is available [here](https://github.com/AbsaOSS/cobrix/blob/master/spark-cobol/src/main/scala/za/co/absa/cobrix/spark/cobol/examples/CobolSparkExample.scala)
In some scenarios Spark is unable to find "cobol" data source by it's short name. In that case you can use the full path to the source class instead: `.format("za.co.absa.cobrix.spark.cobol.source")`
Cobrix assumes input data is encoded in EBCDIC. You can load ASCII files as well by specifying the following option:
`.option("encoding", "ascii")`.
If the input file is a text file (CRLF / LF are used to split records), use
`.option("is_text", "true")`.
Multisegment ASCII text files are supported using this option:
`.option("record_format", "D")`.
Cobrix has better handling of special characters and partial records using its extension format:
`.option("record_format", "D2")`.
Read more on record formats at https://www.ibm.com/docs/en/zos/2.4.0?topic=files-selecting-record-formats-non-vsam-data-sets
### Streaming Cobol binary files from a directory
1. Create a Spark ```StreamContext```
2. Import the binary files/stream conversion manager: ```za.co.absa.spark.cobol.source.streaming.CobolStreamer._```
3. Read the binary files contained in the path informed in the creation of the ```SparkSession``` as a stream: ```... streamingContext.cobolStream()```
4. Apply queries on the stream: ```... stream.filter("some_filter") ...```
5. Start the streaming job.
Below is an example whose full version can be found at ```za.co.absa.cobrix.spark.cobol.examples.StreamingExample```
```scala
val spark = SparkSession
.builder()
.appName("CobolParser")
.master("local[2]")
.config("duration", 2)
.config("copybook", "path_to_the_copybook")
.config("path", "path_to_source_directory") // could be both, local or Hadoop (s3://, hdfs://, etc)
.getOrCreate()
val streamingContext = new StreamingContext(spark.sparkContext, Seconds(3))
import za.co.absa.spark.cobol.source.streaming.CobolStreamer._ // imports the Cobol streams manager
val stream = streamingContext.cobolStream() // streams the binary files into the application
stream
.filter(row => row.getAs[Integer]("NUMERIC_FLD") % 2 == 0) // filters the even values of the nested field 'NUMERIC_FLD'
.print(10)
streamingContext.start()
streamingContext.awaitTermination()
```
### Using Cobrix from a Spark shell
To query mainframe files interactively using `spark-shell` you need to provide jar(s) containing Corbrix and it's dependencies.
This can be done either by downloading all the dependencies as separate jars or by creating an uber jar that contains all
of the dependencies.
#### Getting all Cobrix dependencies
Cobrix's `spark-cobol` data source depends on the COBOL parser that is a part of Cobrix itself.
The jars that you need to get are:
* spark-cobol_2.12-2.9.8.jar
* cobol-parser_2.12-2.9.8.jar
> Versions older than 2.8.0 also need `scodec-core_2.12-1.10.3.jar` and `scodec-bits_2.12-1.1.4.jar`.
> Versions older than 2.7.1 also need `antlr4-runtime-4.8.jar`.
After that you can specify these jars in `spark-shell` command line. Here is an example:
```
$ spark-shell --packages za.co.absa.cobrix:spark-cobol_2.12:2.9.8
or
$ spark-shell --master yarn --deploy-mode client --driver-cores 4 --driver-memory 4G --jars spark-cobol_2.12-2.9.8.jar,cobol-parser_2.12-2.9.8.jar
Setting default log level to "WARN".
To adjust logging level use sc.setLogLevel(newLevel). For SparkR, use setLogLevel(newLevel).
Spark context available as 'sc' (master = yarn, app id = application_1535701365011_2721).
Spark session available as 'spark'.
Welcome to
____ __
/ __/__ ___ _____/ /__
_\ \/ _ \/ _ `/ __/ '_/
/___/ .__/\_,_/_/ /_/\_\ version 2.4.5
/_/
Using Scala version 2.11.8 (OpenJDK 64-Bit Server VM, Java 1.8.0_171)
Type in expressions to have them evaluated.
Type :help for more information.
scala> val df = spark.read.format("cobol").option("copybook", "/data/example1/test3_copybook.cob").load("/data/example1/data")
df: org.apache.spark.sql.DataFrame = [TRANSDATA: struct]
scala> df.show(false)
+----------------------------------------------------+
|TRANSDATA |
+----------------------------------------------------+
|[GBP,S9276511,Beierbauh.,0123330087,1,89341.00] |
|[ZAR,S9276511,Etqutsa Inc.,0039003991,1,2634633.00] |
|[USD,S9276511,Beierbauh.,0038903321,0,75.71] |
|[ZAR,S9276511,Beierbauh.,0123330087,0,215.39] |
|[ZAR,S9276511,Test Bank,0092317899,1,643.94] |
|[ZAR,S9276511,Xingzhoug,8822278911,1,998.03] |
|[USD,S9276511,Beierbauh.,0123330087,1,848.88] |
|[USD,S9276511,Beierbauh.,0123330087,0,664.11] |
|[ZAR,S9276511,Beierbauh.,0123330087,1,55262.00] |
+----------------------------------------------------+
only showing top 20 rows
scala>
```
#### Creating an uber jar
Gathering all dependencies manually maybe a tiresome task. A better approach would be to create a jar file that contains
all required dependencies (an uber jar aka fat jar).
Creating an uber jar for Cobrix is very easy. Steps to build:
- Install JDK 8
- Install SBT
- Clone Cobrix repository
- Run `sbt assembly` in the root directory of the repository specifying the Scala and Spark version you want to build for:
```sh
# For Scala 2.11
sbt -DSPARK_VERSION="2.4.8" ++2.11.12 assembly
# For Scala 2.12
sbt -DSPARK_VERSION="3.3.4" ++2.12.20 assembly
sbt -DSPARK_VERSION="3.4.4" ++2.12.20 assembly
# For Scala 2.13
sbt -DSPARK_VERSION="3.3.4" ++2.13.17 assembly
sbt -DSPARK_VERSION="3.4.4" ++2.13.17 assembly
```
You can collect the uber jar of `spark-cobol` either at
`spark-cobol/target/scala-2.11/` or in `spark-cobol/target/scala-2.12/` depending on the Scala version you used.
The fat jar will have '-bundle' suffix. You can also download pre-built bundles from https://github.com/AbsaOSS/cobrix/releases/tag/v2.7.3
Then, run `spark-shell` or `spark-submit` adding the fat jar as the option.
```sh
$ spark-shell --jars spark-cobol_2.12_3.3-2.9.9-SNAPSHOT-bundle.jar
```
> A note for building and running tests on Windows
> - `java.lang.UnsatisfiedLinkError: org.apache.hadoop.io.nativeio.NativeIO$POSIX.stat` is a Hadoop compatibility with
> Windows issue. The workaround is described here: https://stackoverflow.com/questions/41851066/exception-in-thread-main-java-lang-unsatisfiedlinkerror-org-apache-hadoop-io
> - When running assembly with `-DSPARK_VERSION=...` on Windows, it seems an sbt compatibility with Windows issue:
> https://stackoverflow.com/questions/59144913/run-sbt-1-2-8-project-with-java-d-options-on-windows
> You can work around it by using default Spark version for a given Scala version:
> ```sh
> sbt ++2.11.12 assembly
> sbt ++2.12.20 assembly
> sbt ++2.13.17 assembly
> ```
## Other Features
### Loading several paths
Currently, specifying multiple paths in `load()` is not supported. Use the following syntax:
```scala
spark
.read
.format("cobol")
.option("copybook_contents", copybook)
.option("paths", inputPaths.mkString(","))
.load()
```
### Spark SQL schema extraction
This library also provides convenient methods to extract Spark SQL schemas and Cobol layouts from copybooks.
If you want to extract a Spark SQL schema from a copybook by providing same options you provide to Spark:
```scala
// Same options that you use for spark.read.format("cobol").option()
val options = Map("schema_retention_policy" -> "keep_original")
val cobolSchema = CobolSchema.fromSparkOptions(Seq(copybook), options)
val sparkSchema = cobolSchema.getSparkSchema.toString()
println(sparkSchema)
```
If you want to extract a Spark SQL schema from a copybook using the Cobol parser directly:
```scala
import za.co.absa.cobrix.cobol.parser.CopybookParser
import za.co.absa.cobrix.cobol.reader.policies.SchemaRetentionPolicy
import za.co.absa.cobrix.spark.cobol.schema.CobolSchema
val parsedSchema = CopybookParser.parseSimple(copyBookContents)
val cobolSchema = new CobolSchema(parsedSchema, SchemaRetentionPolicy.CollapseRoot, inputFileNameField = "", generateRecordId = false)
val sparkSchema = cobolSchema.getSparkSchema.toString()
println(sparkSchema)
```
If you want to check the layout of the copybook:
```scala
import za.co.absa.cobrix.cobol.parser.CopybookParser
val copyBook = CopybookParser.parseSimple(copyBookContents)
println(copyBook.generateRecordLayoutPositions())
```
### Spark schema metadata
When a copybook is converted to a Spark schema, some information is lost, such as length of string fields or
minimum and maximum number of elements in arrays. To preserve this information, Cobrix adds metadata to Spark schema
fields. The following metadata is added:
| Metadata key | Description |
|--------------|---------------------------------------------|
| maxLength | The maximum length of a string field. |
| minElements | The minimum number of elements in an array. |
| maxElements | The maximum number of elements in an array. |
You can access the metadata in the usual way:
```scala
// This example returns the maximum length of a string field that is the first field of the copybook
df.schema.fields(0).metadata.getLong("maxLength")
```
### Fixed record length files
Cobrix assumes files has fixed length (`F`) record format by default. The record length is determined by the length of
the record defined by the copybook. But you can specify the record length explicitly:
```
.option("record_format", "F")
.option("record_length", "250")
```
Fixed block record formats (`FB`) are also supported. The support is _experimental_, if you find any issues, please
let us know. When the record format is 'FB' you can specify block length or number of records per
block. As with 'F' if `record_length` is not specified, it will be determined from the copybook.
Records that have BDWs, but not rdws can be read like this:
```
.option("record_format", "FB")
.option("record_length", "250")
```
or simply
```
.option("record_format", "FB")
```
Records that have neither BDWs nor RDWs can be read like this:
```
.option("record_format", "FB")
.option("record_length", "250")
.option("block_length", "500")
```
or
```
.option("record_format", "FB")
.option("record_length", "250")
.option("records_per_block", "2")
```
More on fixed-length record formats: https://www.ibm.com/docs/en/zos/2.3.0?topic=sets-fixed-length-record-formats
### Variable length records support
Cobrix supports variable record length files. The only requirement is that such a file should contain a standard 4 byte
record header known as _Record Descriptor Word_ (RDW). Such headers are created automatically when a variable record length
file is copied from a mainframe. Another type of files are _variable blocked length_. Such files contain _Block Descriptor
Word_ (BDW), as well as Record Descriptor Word (RDW) headers. Any such header can be either big-endian or little-endian.
Also, quite often BDW headers need to be adjusted in order to be read properly. See the use cases section below.
To load variable length record file the following option should be specified:
```
.option("record_format", "V")
```
To load variable blocked length record file the following option should be specified:
```
.option("record_format", "VB")
```
More on record formats: https://www.ibm.com/docs/en/zos/2.3.0?topic=files-selecting-record-formats-non-vsam-data-sets
The space used by the headers (both BDW and RDW) should not be mentioned in the copybook if this option is used. Please refer to the
'Record headers support' section below.
If a record of the copybook contains record lengths for each record you can use 'record_length_field' like this:
```
.option("record_format", "F")
.option("record_length_field", "RECORD_LENGTH")
```
You can use expressions as well:
```
.option("record_format", "F")
.option("record_length_field", "RECORD_LENGTH + 10")
```
or
```
.option("record_format", "F")
.option("record_length_field", "FIELD1 * 10 + 200")
```
If the record field contains a string that can be mapped to a record size, you can add the mapping as a JSON:
```
.option("record_format", "F")
.option("record_length_field", "FIELD_STR")
.option("record_length_map", """{"SEG1":100,"SEG2":200}""")
```
You can specify the default record size by defining the key "_":
```
.option("record_format", "F")
.option("record_length_field", "FIELD_STR")
.option("record_length_map", """{"SEG1":100,"SEG2":200,"_":100}""")
```
### Use cases for various variable length formats
In order to understand the file format it is often sufficient to look at the first 4 bytes of the file (un case of RDW only files),
or the first 8 bytes of a file + lookup the offset of the block (in case of BDW + RDW)
#### V header examples (have only RDW headers)
In order to determine if an RDW is a big- or little-endian, take a look at the first 4 bytes. If the first 2 bytes are zeros,
it's a little-endian RDW header, otherwise it is a big-endian RDW header.
| Header example | Description | Options |
| -------------- |:---------------------------------------------------------------------- | :----------------
| `00 10 00 00` | Big-endian RDW, no adjustments,
the record size: `0x10 = 16 bytes` | `.option("record_format", "V")`
`.option("is_rdw_big_endian", "true")` |
| `01 10 00 00` | Big-endian RDW, adjustment `-2`,
the record size: `0x01*256 + 0x10 - 2 = 256 + 16 + 2 = 270 bytes` | `.option("record_format", "V")`
`.option("is_rdw_big_endian", "true")`
`.option("rdw_adjustment", -2)` |
| `00 00 10 00` | Little-endian RDW, no adjustments,
the record size: `0x10 = 16 bytes` | `.option("record_format", "V")`
`.option("is_rdw_big_endian", "false")` |
| `00 00 10 01` | Little-endian RDW, adjustment `-2`,
the record size: `0x01*256 + 0x10 - 2 = 256 + 16 + 2 = 270 bytes` | `.option("record_format", "V")`
`.option("is_rdw_big_endian", "false")`
`.option("rdw_adjustment", -2)` |
#### VB header examples (have both BDW and RDW headers)
It is harder to determine if a BDW header is big- or little-endian since BDW header bytes can be all non-zero.
But for VB format RDWs follow BDWs and endiness. You can determine the endiness from an RDW, and use the same option for BDW.
| Header example | Description | Options |
| ---------------------------------------- |:--------------------------------------------------------------- | :----------------
| `00 28 00 00` `00 10 00 00` (BDW, RDW) | Big-endian BDW+RDW, no adjustments,
BDW = `0x28 = 40 byes`
the record size: `0x10 = 16 bytes` | `.option("record_format", "VB")`
`.option("is_bdw_big_endian", "true")`
`.option("is_rdw_big_endian", "true")` |
| `00 2C 00 00` `00 10 00 00` (BDW, RDW) | Big-endian BDW+RDW, need -4 byte adjustment since BDW includes its own length,
BDW = `0x2C - 4 = 40 byes`
the record size: `0x10 = 16 bytes` | `.option("record_format", "VB")`
`.option("is_bdw_big_endian", "true")`
`.option("is_rdw_big_endian", "true")`
`.option("rdw_adjustment", -4)` |
| `00 00 28 00` `00 00 10 00` (BDW, RDW) | Little-endian BDW+RDW, no adjustments,
BDW = `0x28 = 40 byes`
the record size: `0x10 = 16 bytes` | `.option("record_format", "VB")`
`.option("is_bdw_big_endian", "false")`
`.option("is_rdw_big_endian", "false")` |
| `00 00 2C 00` `00 00 10 00` (BDW, RDW) | Little-endian BDW+RDW, need -4 byte adjustment since BDW includes its own length,
BDW = `0x2C - 4 = 40 byes`
the record size: `0x10 = 16 bytes` | `.option("record_format", "VB")`
`.option("is_bdw_big_endian", "false")`
`.option("is_rdw_big_endian", "false")`
`.option("rdw_adjustment", -4)` |
### Schema collapsing
Mainframe data often contain only one root GROUP. In such cases such a GROUP can be considered something similar to XML rowtag.
Cobrix allows either to collapse or to retain the GROUP. To turn this on use the following option:
```scala
.option("schema_retention_policy", "collapse_root")
```
or
```scala
.option("schema_retention_policy", "keep_original")
```
Let's look at an example. Let's say we have a copybook that looks like this:
```cobol
01 RECORD.
05 ID PIC S9(4) COMP.
05 COMPANY.
10 SHORT-NAME PIC X(10).
10 COMPANY-ID-NUM PIC 9(5) COMP-3.
```
When "schema_retention_policy" is set to "collapse_root" (default), the root group will be collapsed and the schema will look
like this (note the RECORD field is not part of the schema):
```
root
|-- ID: integer (nullable = true)
|-- COMPANY: struct (nullable = true)
| |-- SHORT_NAME: string (nullable = true)
| |-- COMPANY_ID_NUM: integer (nullable = true)
```
But when "schema_retention_policy" is set to "keep_original", the schema will look like this (note the RECORD field is part of the schema):
```
root
|-- RECORD: struct (nullable = true)
| |-- ID: integer (nullable = true)
| |-- COMPANY: struct (nullable = true)
| | |-- SHORT_NAME: string (nullable = true)
| | |-- COMPANY_ID_NUM: integer (nullable = true)
```
You can experiment with this feature using built-in example in `za.co.absa.cobrix.spark.cobol.examples.CobolSparkExample`
### Record Id fields generation
For data that has record order dependency generation of "File_Id", "Record_Id", and "Record_Byte_Length" fields is
supported. The values of the File_Id column will be unique for each file when a directory is specified as the source for
data. The values of the Record_Id column will be unique and sequential record identifiers within the file.
Turn this feature on use
```
.option("generate_record_id", true)
```
The following fields will be added to the top of the schema:
```
root
|-- File_Id: integer (nullable = false)
|-- Record_Id: long (nullable = false)
|-- Record_Byte_Length: integer (nullable = false)
```
You can use this option to generate raw bytes of each record as a binary field:
```
.option("generate_record_bytes", "true")
```
The following fields will be added to the top of the schema:
```
root
|-- Record_Bytes: binary (nullable = false)
```
You can generate `_corrupt_fields` that will contain original binary values of fields Cobrix was unable to decode:
```scala
.option("generate_corrupt_fields", "true")
```
### Locality optimization for variable-length records parsing
Variable-length records depend on headers to have their length calculated, which makes it hard to achieve parallelism while parsing.
Cobrix strives to overcome this drawback by performing a two-stages parsing. The first stage traverses the records retrieving their lengths
and offsets into structures called indexes. Then, the indexes are distributed across the cluster, which allows for parallel variable-length
records parsing.
However effective, this strategy may also suffer from excessive shuffling, since indexes may be sent to executors far from the actual data.
The latter issue is overcome by extracting the preferred locations for each index directly from HDFS/S3/..., and then passing those locations to
Spark during the creation of the RDD that distributes the indexes.
When processing large collections, the overhead of collecting the locations is offset by the benefits of locality, thus, this feature is
enabled by default, but can be disabled by the configuration below:
```
.option("improve_locality", false)
```
### Workload optimization for variable-length records parsing
This feature works only for HDFS, not for any other of Hadoop filesystems.
When dealing with variable-length records, Cobrix strives to maximize locality by identifying the preferred locations in the cluster to parse
each record, i.e. the nodes where the record resides.
This feature is implemented by querying HDFS about the locations of the blocks containing each record and instructing Spark to create the
partition for that record in one of those locations.
However, sometimes, new nodes can be added to the cluster after the Cobol file is stored, in which case those nodes would be ignored when
processing the file since they do not contain any record.
To overcome this issue, Cobrix also strives to re-balance the records among the new nodes at parsing time, as an attempt to maximize the
utilization of the cluster. This is done through identifying the busiest nodes and sharing part of their burden with the new ones.
Since this is not an issue present in most cluster configurations, this feature is disabled by default, and can be enabled from the
configuration below:
```
.option("optimize_allocation", true)
```
If however the option ```improve_locality``` is disabled, this option will also be disabled regardless of the value in ```optimize_allocation```.
### Record headers support
As you may already know a file in the mainframe world does not mean the same as in the PC world. On PCs we think of a file
as a stream of bytes that we can open, read/write and close. On mainframes a file can be a set of records that we can query.
Record is a blob of bytes, can have different size. Mainframe's 'filesystem' handles the mapping between logical records
and physical location of data.
> _Details are available at this [Wikipedia article](https://en.wikipedia.org/wiki/MVS) (look for MVS filesystem)._
So usually a file cannot simply be 'copied' from a mainframe. When files are transferred using tools like XCOM each
record is prepended with an additional *record header* or *RDW*. This header allows readers of a file in PC to restore the
'set of records' nature of the file.
Mainframe files coming from IMS and copied through specialized tools contain records (the payload) having schema of DBs
copybook warped with DB export tool headers wrapped with record headers. Like this:
RECORD_HEADERS ( TOOL_HEADERS ( PAYLOAD ) )
> _Similar to Internet's TCP protocol IP_HEADERS ( TCP_HEADERS ( PAYLOAD ) )._
TOOL_HEADERS are application dependent. Often it contains the length of the payload. But this length is sometime
not very reliable. RECORD_HEADERS contain the record length (including TOOL_HEADERS length) and are proved to be reliable.
For fixed record length files record headers can be ignored since we already know the record length. But for variable
record length files and for multisegment files record headers can be considered the most reliable single point of truth
about record length.
You can instruct the reader to use 4 byte record headers to extract records from a mainframe file.
```
.option("record_format", "V")
```
This is very helpful for multisegment files when segments have different lengths. Since each segment has it's own
copybook it is very convenient to extract segments one by one by combining `record_format = V` option with segment
filter option.
```
.option("segment_field", "SEG-ID")
.option("segment_filter", "1122334")
```
In this example it is expected that the copybook has a field with the name 'SEG-ID'. The data source will read all
segments, but will parse only ones that have `SEG-ID = "1122334"`.
If you want to parse multiple segments, set the option 'segment_filter' to a comma separated list of the segment values.
For example:
```
.option("segment_field", "SEG-ID")
.option("segment_filter", "1122334,1122335")
```
will only parse the records with `SEG-ID = "1122334" OR SEG-ID = "1122335"`
### Custom record extractors
Custom record extractors can be used for customizing splitting of input files into a set of records. Cobrix supports
text files, fixed length binary files and binary files with RDWs. If your input file is not in one of the supported
formats you can implement a custom record extractor interface and provide it to `spark-cobol` as a option:
```
.option("record_extractor", "com.example.record.header.parser")
```
A custom record extractor needs to be a class having this precise constructor signature:
```scala
class TextRecordExtractor(ctx: RawRecordExtractorParameters) extends Serializable with RawRecordExtractor {
// Your implementation
}
```
A record extractor is essentially iterator of records. Each returned record is an array of bytes parsable by the
copybook.
A record extractor is invoked two times. First, it is invoked at the beginning each file to go thought the file and
create a sparse index. The second time it is invoked by parallel processes starting from different records in the file.
The starting record number is provided in constructor. The starting file offset is available from `inputStream`.
RawRecordContext consists of the following fields that the custom record extractor will get from Cobrix
in runtime:
* `startingRecordNumber` - A record number the input stream is pointing to.
* `inputStream` - The input stream of bytes of the input file.
* `copybook` - The parsed copybook of the input stream.
* `additionalInfo` - An arbitrary info that can be passed as an option (see below).
If your record extractor needs additional information in order to extract records properly, you can provide
an arbitrary additional info to the record extracted at runtime by specifying this option:
Take a look at `CustomRecordExtractorMock` inside `spark-cobol` project to see how a custom record extractor can be built.
```
.option("re_additional_info", "some info")
```
### Custom record header parsers (deprecated)
Custom record header parsers are deprecated. Use custom record extractors instead. They are more flexible and easier to use.
If your variable length file does not have RDW headers, but has fields that can be used for determining record lengths
you can provide a custom record header parser that takes starting bytes of each record and returns record lengths.
In order to do that you need to create a class inheriting `RecordHeaderParser` and `Serializable` traits and provide a
fully qualified class name to the following option:
```
.option("record_header_parser", "com.example.record.header.parser")
```
### RDDs
Cobrix provides helper methods to convert `RDD[String]` or `RDD[Array[Byte]]` to `DataFrame` using a copybook.
This can be used if you want to use a custom logic to split the input file into records as either ASCII strings
or arrays of bytes, and then parse each record using a copybook.
An example of `RDD[Array[Byte]]`:
```scala
import za.co.absa.cobrix.spark.cobol.Cobrix
val rdd = ???
val df = Cobrix.fromRdd
.copybookContents(copybook)
.option("encoding", "ebcdic") // any supported option
.load(rdd)
```
An example of ASCII Strings `RDD[String]`:
```scala
import za.co.absa.cobrix.spark.cobol.Cobrix
val rdd = ???
val df = Cobrix.fromRdd
.copybookContents(copybook)
.option("variable_size_occurs", "true") // any supported option
.loadText(rdd)
```
When converting from an RDD some of the options like `record_format` or `generate_record_id` cannot be used since the
data is assumed to be already split by records and the information about file names and relative order of records is not available.
## EBCDIC code pages
The following code pages are supported:
* `common` - (default) EBCDIC common characters
* `common_extended` - EBCDIC common characters with special characters extension
* `cp037` - IBM EBCDIC US-Canada
* `cp037_extended` - IBM EBCDIC US-Canada with special characters extension
* `cp300` - IBM EBCDIC Japanese Extended (2 byte code page)
* `cp838` - IBM EBCDIC Thailand
* `cp870` - IBM EBCDIC Multilingual Latin-2
* `cp875` - IBM EBCDIC Greek
* `cp1025` - IBM EBCDIC Multilingual Cyrillic
* `cp1047` - IBM EBCDIC Latin-1/Open System
* `cp1364` - (experimental support) IBM EBCDIC Korean (2 byte code page)
* `cp1388` - (experimental support) IBM EBCDIC Simplified Chinese (2 byte code page)
By default, Cobrix uses common EBCDIC code page which contains only basic latin characters, numbers, and punctuation.
You can specify the code page to use for all string fields by setting the `ebcdic_code_page` option to one of the
following values:
```
.option("ebcdic_code_page", "cp037")
```
For multi-codepage files, you can specify the code page to use for each field by setting the `field_code_page:` option
```
.option("ebcdic_code_page", "cp037")
.option("field_code_page:cp1256" -> "FIELD1")
.option("field_code_page:us-ascii" -> "FIELD-2, FIELD_3")
```
## Reading ASCII text file
Cobrix is primarily designed to read binary files, but you can directly use some internal functions to read ASCII text files. In ASCII text files, records are separated with newlines.
Working example 1:
```scala
// The recommended way
val df = spark
.read
.format("cobol")
.option("copybook_contents", copybook)
.option("ascii_charset", "ISO-8859-1") // You can choose a charset, UTF-8 is used by default
.option("record_format", "D")
.load(tmpFileName)
````
Working example 2 - Using RDDs and helper methods:
```scala
// This is the way if you have data converted to an RDD[String] already.
// You have full control on reading the input data records and converting them to `java.lang.String`.
val df = Cobrix.fromRdd
.copybookContents(copybook)
.option("variable_size_occurs", "true") // any supported option
.loadText(rdd)
````
Working example 3 - Using RDDs and record parsers directly:
```scala
// This is the most verbose way - creating dataframes from RDDs. But it gives full control on how text files are
// processed before parsing actual records
val spark = SparkSession
.builder()
.appName("Spark-Cobol ASCII text file")
.master("local[*]")
.getOrCreate()
val copybook =
""" 01 COMPANY-DETAILS.
| 05 SEGMENT-ID PIC 9(1).
| 05 STATIC-DETAILS.
| 10 NAME PIC X(2).
|
| 05 CONTACTS REDEFINES STATIC-DETAILS.
| 10 PERSON PIC X(3).
""".stripMargin
val parsedCopybook = CopybookParser.parse(copybook, dataEnncoding = ASCII, stringTrimmingPolicy = StringTrimmingPolicy.TrimNone)
val cobolSchema = new CobolSchema(parsedCopybook, SchemaRetentionPolicy.CollapseRoot, "", false)
val sparkSchema = cobolSchema.getSparkSchema
val rddText = spark.sparkContext.textFile("src/main/resources/mini.txt")
val recordHandler = new RowHandler()
val rddRow = rddText
.filter(str => str.length > 0)
.map(str => {
val record = RecordExtractors.extractRecord[GenericRow](parsedCopybook.ast,
str.getBytes(),
0,
SchemaRetentionPolicy.CollapseRoot, handler = recordHandler)
Row.fromSeq(record)
})
val dfOut = spark.createDataFrame(rddRow, sparkSchema)
dfOut.printSchema()
dfOut.show()
```
Corresponding data sample in `mini.txt`:
```
1BB
2CCC
```
Output:
```
root
|-- SEGMENT_ID: integer (nullable = true)
|-- STATIC_DETAILS: struct (nullable = true)
| |-- NAME: string (nullable = true)
|-- CONTACTS: struct (nullable = true)
| |-- PERSON: string (nullable = true)
...
+----------+--------------+--------+
|SEGMENT_ID|STATIC_DETAILS|CONTACTS|
+----------+--------------+--------+
| 1| [BB]| [null]|
| 2| [CC]| [CCC]|
+----------+--------------+--------+
```
There, Cobrix loaded all redefines for every record. Each record contains data from all of the segments. But only one redefine is valid for every segment. Filtering is described in the following section.
## Automatic segment redefines filtering
When reading a multisegment file you can use Spark to clean up redefines that do not match segment ids. Cobrix will parse
every redefined field for each segment. To increase performance you can specify which redefine corresponds to which
segment id. This way Cobrix will parse only relevant segment redefined fields and leave the rest of the redefined fields null.
```
.option("redefine-segment-id-map:0", "REDEFINED_FIELD1 => SegmentId1,SegmentId2,...")
.option("redefine-segment-id-map:1", "REDEFINED_FIELD2 => SegmentId10,SegmentId11,...")
```
For the above example the load options will lok like this (last 2 options):
```scala
val df = spark
.read
.format("cobol")
.option("copybook_contents", copybook)
.option("record_format", "V")
.option("segment_field", "SEGMENT_ID")
.option("segment_id_level0", "C")
.option("segment_id_level1", "P")
.option("redefine_segment_id_map:0", "STATIC-DETAILS => C")
.option("redefine_segment_id_map:1", "CONTACTS => P")
.load("examples/multisegment_data/COMP.DETAILS.SEP30.DATA.dat")
```
The filtered data will look like this:
```
df.show(10)
+----------+----------+--------------------+--------------------+
|SEGMENT_ID|COMPANY_ID| STATIC_DETAILS| CONTACTS|
+----------+----------+--------------------+--------------------+
| C|9377942526|[Joan Q & Z,10 Sa...| |
| P|9377942526| |[+(277) 944 44 55...|
| C|3483483977|[Robotrd Inc.,2 P...| |
| P|3483483977| |[+(174) 970 97 54...|
| P|3483483977| |[+(848) 832 61 68...|
| P|3483483977| |[+(455) 184 13 39...|
| C|7540764401|[Eqartion Inc.,87...| |
| C|4413124035|[Xingzhoug,74 Qin...| |
| C|9546291887|[ZjkLPj,5574, Tok...| |
| P|9546291887| |[+(300) 252 33 17...|
+----------+----------+--------------------+--------------------+
```
In the above example invalid fields became `null` and the parsing is done faster because Cobrix does not need to process
every redefine for each record.
## Group Filler dropping
A FILLER is an anonymous field that is usually used for reserving space for new fields in a fixed record length data.
Or it is used to remove a field from a copybook without affecting compatibility.
```cobol
05 COMPANY.
10 NAME PIC X(15).
10 FILLER PIC X(5).
10 ADDRESS PIC X(25).
10 FILLER PIC X(125).
```
Such fields are dropped when imported into a Spark data frame by Cobrix. Some copybooks, however, have FILLER groups that
contain non-filler fields. For example,
```cobol
05 FILLER.
10 NAME PIC X(15).
10 ADDRESS PIC X(25).
05 FILLER.
10 AMOUNT PIC 9(10)V96.
10 COMMENT PIC X(40).
```
By default Cobrix will retain such fields, but will rename each such filler to a unique name so each each individual struct
can be specified unambiguously. For example, in this case the filler groups will be renamed to `FILLER_1` and `FILLER_2`.
You can change this behaviour if you would like to drop such filler groups by providing this option:
```
.option("drop_group_fillers", "true")
```
In order to retain *value FILLERs* (e.g. non-group FILLERs) as well, use this option:
```
.option("drop_value_fillers", "false")
```
## Reading hierarchical data sets
Let's imagine we have a multisegment file with 2 segments having parent-child relationships. Each segment has a different
record type. The root record/segment contains company info, an address and a taxpayer number. The child segment contains
a contact person for a company. Each company can have zero or more contact persons. So each root record can be followed by
zero or more child records.
To load such data in Spark the first thing you need to do is to create a copybook that contains all segment specific fields
in redefined groups. Here is the copybook for our example:
```cobol
01 COMPANY-DETAILS.
05 SEGMENT-ID PIC X(5).
05 COMPANY-ID PIC X(10).
05 STATIC-DETAILS.
10 COMPANY-NAME PIC X(15).
10 ADDRESS PIC X(25).
10 TAXPAYER.
15 TAXPAYER-TYPE PIC X(1).
15 TAXPAYER-STR PIC X(8).
15 TAXPAYER-NUM REDEFINES TAXPAYER-STR
PIC 9(8) COMP.
05 CONTACTS REDEFINES STATIC-DETAILS.
10 PHONE-NUMBER PIC X(17).
10 CONTACT-PERSON PIC X(28).
```
The 'SEGMENT-ID' and 'COMPANY-ID' fields are present in all of the segments. The 'STATIC-DETAILS' group is present only in
the root record. The 'CONTACTS' group is present only in child record. Notice that 'CONTACTS' redefine 'STATIC-DETAILS'.
Because the records have different lengths use `record_format = V` or `record_format = VB` depending of the record format.
If you load this file as is you will get the schema and the data similar to this.
#### Spark App:
```scala
val df = spark
.read
.format("cobol")
.option("copybook", "/path/to/thecopybook")
.option("record_format", "V")
.load("examples/multisegment_data")
```
#### Schema
```
df.printSchema()
root
|-- SEGMENT_ID: string (nullable = true)
|-- COMPANY_ID: string (nullable = true)
|-- STATIC_DETAILS: struct (nullable = true)
| |-- COMPANY_NAME: string (nullable = true)
| |-- ADDRESS: string (nullable = true)
| |-- TAXPAYER: struct (nullable = true)
| | |-- TAXPAYER_TYPE: string (nullable = true)
| | |-- TAXPAYER_STR: string (nullable = true)
| | |-- TAXPAYER_NUM: integer (nullable = true)
|-- CONTACTS: struct (nullable = true)
| |-- PHONE_NUMBER: string (nullable = true)
| |-- CONTACT_PERSON: string (nullable = true)
```
#### Data sample
```
df.show(10)
+----------+----------+--------------------+--------------------+
|SEGMENT_ID|COMPANY_ID| STATIC_DETAILS| CONTACTS|
+----------+----------+--------------------+--------------------+
| C|9377942526|[Joan Q & Z,10 Sa...|[Joan Q & Z 1...|
| P|9377942526|[+(277) 944 44 5,...|[+(277) 944 44 55...|
| C|3483483977|[Robotrd Inc.,2 P...|[Robotrd Inc. 2...|
| P|3483483977|[+(174) 970 97 5,...|[+(174) 970 97 54...|
| P|3483483977|[+(848) 832 61 6,...|[+(848) 832 61 68...|
| P|3483483977|[+(455) 184 13 3,...|[+(455) 184 13 39...|
| C|7540764401|[Eqartion Inc.,87...|[Eqartion Inc. 8...|
| C|4413124035|[Xingzhoug,74 Qin...|[Xingzhoug 7...|
| C|9546291887|[ZjkLPj,5574, Tok...|[ZjkLPj 5...|
| P|9546291887|[+(300) 252 33 1,...|[+(300) 252 33 17...|
+----------+----------+--------------------+--------------------+
```
As you can see Cobrix loaded *all* redefines for *every* record. Each record contains data from all of the segments. But only
one redefine is valid for every segment. So we need to split the data set into 2 datasets or tables. The distinguisher is
the 'SEGMENT_ID' field. All company details will go into one data sets (segment id = 'C' [company]) while contacts will go in
the second data set (segment id = 'P' [person]). While doing the split we can also collapse the groups so the table won't
contain nested structures. This can be helpful to simplify the analysis of the data.
While doing it you might notice that the taxpayer number field is actually a redefine. Depending on the 'TAXPAYER_TYPE'
either 'TAXPAYER_NUM' or 'TAXPAYER_STR' is used. We can resolve this in our Spark app as well.
### Automatic reconstruction of hierarchical record structure
Starting from `spark-cobol` version `1.1.0` hierarchical structure of multisegment records can be restored automatically. In order to do this you
need to provide:
- A segment ID field that will be used to distinguish segment types.
- A segmentId to redefine fields mapping that will be used to map each segment to a redefine field.
- A parent-child relationship between segments identified by segment redefine fields.
When all of the above is specified Cobrix can reconstruct hierarchical nature of records by making child segments nested
arrays of parent segments. Arbitrary levels of hierarchy and arbitrary number of segments is supported.
```scala
val df = spark
.read
.format("cobol")
.option("copybook", "/path/to/thecopybook")
.option("record_format", "V")
// Specifies a field containing a segment id
.option("segment_field", "SEGMENT_ID")
// Specifies a mapping between segment ids and segment redefine fields
.option("redefine_segment_id_map:1", "STATIC-DETAILS => C")
.option("redefine-segment-id-map:2", "CONTACTS => P")
// Specifies a parent-child relationship
.option("segment-children:1", "STATIC-DETAILS => CONTACTS")
.load("examples/multisegment_data")
```
The output schema will be
```
scala> df.printSchema()
root
|-- SEGMENT_ID: string (nullable = true)
|-- COMPANY_ID: string (nullable = true)
|-- STATIC_DETAILS: struct (nullable = true)
| |-- COMPANY_NAME: string (nullable = true)
| |-- ADDRESS: string (nullable = true)
| |-- TAXPAYER: struct (nullable = true)
| | |-- TAXPAYER_TYPE: string (nullable = true)
| | |-- TAXPAYER_STR: string (nullable = true)
| | |-- TAXPAYER_NUM: integer (nullable = true)
| |-- CONTACTS: array (nullable = true)
| | |-- element: struct (containsNull = true)
| | | |-- PHONE_NUMBER: string (nullable = true)
| | | |-- CONTACT_PERSON: string (nullable = true)
```
Notice that contacts now is an array of structs. That is a company static details can contain zero or mor contacts.
A possible hierarchical record output is
```
scala> import za.co.absa.cobrix.spark.cobol.utils.SparkUtils
scala> println(SparkUtils.prettyJSON(df.toJSON.take(1).mkString("[", ", ", "]")))
{
"SEGMENT_ID" : "C",
"COMPANY_ID" : "9377942526",
"STATIC_DETAILS" : {
"COMPANY_NAME" : "Joan Q & Z",
"ADDRESS" : "10 Sandton, Johannesburg",
"TAXPAYER" : {
"TAXPAYER_TYPE" : "A",
"TAXPAYER_STR" : "92714306",
"TAXPAYER_NUM" : 959592241
},
"CONTACTS" : [ {
"PHONE_NUMBER" : "+(174) 970 97 54",
"CONTACT_PERSON" : "Tyesha Debow"
}, {
"PHONE_NUMBER" : "+(848) 832 61 68",
"CONTACT_PERSON" : "Mindy Celestin"
}, {
"PHONE_NUMBER" : "+(455) 184 13 39",
"CONTACT_PERSON" : "Mabelle Winburn"
} ]
}
}
```
An advanced hierarchical example with multiple levels of nesting and multiple segments on each level
is available as a unit test `za/co/absa/cobrix/spark/cobol/source/integration/Test17HierarchicalSpec.scala`.
### Manual reconstruction of hierarchical structure
Alternatively, hierarchical record structure can be reconstructed manually by extracting each segment and joining
segments together. This a is more complicated process, but it provides more control.
#### Getting the first segment
```scala
import spark.implicits._
val dfCompanies = df
// Filtering the first segment by segment id
.filter($"SEGMENT_ID"==="C")
// Selecting fields that are only available in the first segment
.select($"COMPANY_ID", $"STATIC_DETAILS.COMPANY_NAME", $"STATIC_DETAILS.ADDRESS",
// Resolving the taxpayer redefine
when($"STATIC_DETAILS.TAXPAYER.TAXPAYER_TYPE" === "A", $"STATIC_DETAILS.TAXPAYER.TAXPAYER_STR")
.otherwise($"STATIC_DETAILS.TAXPAYER.TAXPAYER_NUM").cast(StringType).as("TAXPAYER"))
```
The resulting table looks like this:
```
dfCompanies.show(10, truncate = false)
+----------+-------------+-------------------------+--------+
|COMPANY_ID|COMPANY_NAME |ADDRESS |TAXPAYER|
+----------+-------------+-------------------------+--------+
|9377942526|Joan Q & Z |10 Sandton, Johannesburg |92714306|
|3483483977|Robotrd Inc. |2 Park ave., Johannesburg|31195396|
|7540764401|Eqartion Inc.|871A Forest ave., Toronto|87432264|
|4413124035|Xingzhoug |74 Qing ave., Beijing |50803302|
|9546291887|ZjkLPj |5574, Tokyo |73538919|
|9168453994|Test Bank |1 Garden str., London |82573513|
|4225784815|ZjkLPj |5574, Tokyo |96136195|
|8463159728|Xingzhoug |74 Qing ave., Beijing |17785468|
|8180356010|Eqartion Inc.|871A Forest ave., Toronto|79054306|
|7107728116|Xingzhoug |74 Qing ave., Beijing |70899995|
+----------+-------------+-------------------------+--------+
```
This looks like a valid and clean table containing the list of companies. Now let's do the same for the second segment.
#### Getting the second segment
```scala
val dfContacts = df
// Filtering the second segment by segment id
.filter($"SEGMENT_ID"==="P")
// Selecting the fields only valid for the second segment
.select($"COMPANY_ID", $"CONTACTS.CONTACT_PERSON", $"CONTACTS.PHONE_NUMBER")
```
The resulting data loons like this:
```
dfContacts.show(10, truncate = false)
+----------+--------------------+----------------+
|COMPANY_ID|CONTACT_PERSON |PHONE_NUMBER |
+----------+--------------------+----------------+
|9377942526|Janiece Newcombe |+(277) 944 44 55|
|3483483977|Tyesha Debow |+(174) 970 97 54|
|3483483977|Mindy Celestin |+(848) 832 61 68|
|3483483977|Mabelle Winburn |+(455) 184 13 39|
|9546291887|Carrie Celestin |+(300) 252 33 17|
|9546291887|Edyth Deveau |+(907) 101 70 64|
|9546291887|Jene Norgard |+(694) 918 17 44|
|9168453994|Timika Bourke |+(768) 691 44 85|
|9168453994|Lynell Riojas |+(695) 918 33 16|
|4225784815|Jene Mackinnon |+(540) 937 33 71|
+----------+--------------------+----------------+
```
This looks good as well. The table contains the list of contact persons for companies. This data set contains the
'COMPANY_ID' field which we can use later to join the tables. But often there are no such fields in data imported from
hierarchical databases. If that is the case Cobrix can help you craft such fields automatically. Use 'segment_field' to
specify a field that contain the segment id. Use 'segment_id_level0' to ask Cobrix to generate ids for the particular
segments. We can use 'segment_id_level1' to generate child ids as well. If children records can contain children of their
own we can use 'segment_id_level2' etc.
#### Generating segment ids
```scala
val df = spark
.read
.format("cobol")
.option("copybook_contents", copybook)
.option("record_format", "V")
.option("segment_field", "SEGMENT_ID")
.option("segment_id_level0", "C")
.option("segment_id_level1", "P")
.load("examples/multisegment_data/COMP.DETAILS.SEP30.DATA.dat")
```
Sometimes, the leaf level has many segments. In this case, you can use `_` as the list of segment ids to specify
'the rest of segment ids', like this:
```scala
val df = spark
.read
.format("cobol")
.option("copybook_contents", copybook)
.option("record_format", "V")
.option("segment_field", "SEGMENT_ID")
.option("segment_id_level0", "C")
.option("segment_id_level1", "_")
.load("examples/multisegment_data/COMP.DETAILS.SEP30.DATA.dat")
```
The result of both above code snippets is the same.
The resulting table will look like this:
```
df.show(10)
+------------------+-----------------------+----------+----------+--------------------+--------------------+
| Seg_Id0| Seg_Id1|SEGMENT_ID|COMPANY_ID| STATIC_DETAILS| CONTACTS|
+------------------+-----------------------+----------+----------+--------------------+--------------------+
|20181219130609_0_0| null| C|9377942526|[Joan Q & Z,10 Sa...|[Joan Q & Z 1...|
|20181219130609_0_0|20181219130723_0_0_L1_1| P|9377942526|[+(277) 944 44 5,...|[+(277) 944 44 55...|
|20181219130609_0_2| null| C|3483483977|[Robotrd Inc.,2 P...|[Robotrd Inc. 2...|
|20181219130609_0_2|20181219130723_0_2_L1_1| P|3483483977|[+(174) 970 97 5,...|[+(174) 970 97 54...|
|20181219130609_0_2|20181219130723_0_2_L1_2| P|3483483977|[+(848) 832 61 6,...|[+(848) 832 61 68...|
|20181219130609_0_2|20181219130723_0_2_L1_3| P|3483483977|[+(455) 184 13 3,...|[+(455) 184 13 39...|
|20181219130609_0_6| null| C|7540764401|[Eqartion Inc.,87...|[Eqartion Inc. 8...|
|20181219130609_0_7| null| C|4413124035|[Xingzhoug,74 Qin...|[Xingzhoug 7...|
|20181219130609_0_8| null| C|9546291887|[ZjkLPj,5574, Tok...|[ZjkLPj 5...|
|20181219130609_0_8|20181219130723_0_8_L1_1| P|9546291887|[+(300) 252 33 1,...|[+(300) 252 33 17...|
+------------------+-----------------------+----------+----------+--------------------+--------------------+
```
The data now contain 2 additional fields: 'Seg_Id0' and 'Seg_Id1'. The 'Seg_Id0' is an autogenerated id for each root
record. It is also unique for a root record. After splitting the segments you can use Seg_Id0 to join both tables.
The 'Seg_Id1' field contains a unique child id. It is equal to 'null' for all root records but uniquely identifies
child records.
You can now split these 2 segments and join them by Seg_Id0. The full example is available at
`spark-cobol/src/main/scala/za/co/absa/cobrix/spark/cobol/examples/CobolSparkExample2.scala`
To run it from an IDE you'll need to change Scala and Spark dependencies from 'provided' to 'compile' so the
jar file would contain all the dependencies. This is because Cobrix is a library to be used in Spark job projects.
Spark jobs uber jars should not contain Scala and Spark dependencies since Hadoop clusters have their Scala and Spark
dependencies provided by the infrastructure. Including Spark and Scala dependencies in an uber jar can produce
binary incompatibilities when these jars are used in `spark-submit` and `spark-shell`.
Here is our example tables to join:
##### Segment 1 (Companies)
```
dfCompanies.show(10, truncate = false)
+--------------------+----------+-------------+-------------------------+--------+
|Seg_Id0 |COMPANY_ID|COMPANY_NAME |ADDRESS |TAXPAYER|
+--------------------+----------+-------------+-------------------------+--------+
|20181219130723_0_0 |9377942526|Joan Q & Z |10 Sandton, Johannesburg |92714306|
|20181219130723_0_2 |3483483977|Robotrd Inc. |2 Park ave., Johannesburg|31195396|
|20181219130723_0_6 |7540764401|Eqartion Inc.|871A Forest ave., Toronto|87432264|
|20181219130723_0_7 |4413124035|Xingzhoug |74 Qing ave., Beijing |50803302|
|20181219130723_0_8 |9546291887|ZjkLPj |5574, Tokyo |73538919|
|20181219130723_0_12 |9168453994|Test Bank |1 Garden str., London |82573513|
|20181219130723_0_15 |4225784815|ZjkLPj |5574, Tokyo |96136195|
|20181219130723_0_20 |8463159728|Xingzhoug |74 Qing ave., Beijing |17785468|
|20181219130723_0_24 |8180356010|Eqartion Inc.|871A Forest ave., Toronto|79054306|
|20181219130723_0_27 |7107728116|Xingzhoug |74 Qing ave., Beijing |70899995|
+--------------------+----------+-------------+-------------------------+--------+
```
##### Segment 2 (Contacts)
```
dfContacts.show(13, truncate = false)
+-------------------+----------+-------------------+----------------+
|Seg_Id0 |COMPANY_ID|CONTACT_PERSON |PHONE_NUMBER |
+-------------------+----------+-------------------+----------------+
|20181219130723_0_0 |9377942526|Janiece Newcombe |+(277) 944 44 55|
|20181219130723_0_2 |3483483977|Tyesha Debow |+(174) 970 97 54|
|20181219130723_0_2 |3483483977|Mindy Celestin |+(848) 832 61 68|
|20181219130723_0_2 |3483483977|Mabelle Winburn |+(455) 184 13 39|
|20181219130723_0_8 |9546291887|Carrie Celestin |+(300) 252 33 17|
|20181219130723_0_8 |9546291887|Edyth Deveau |+(907) 101 70 64|
|20181219130723_0_8 |9546291887|Jene Norgard |+(694) 918 17 44|
|20181219130723_0_12|9168453994|Timika Bourke |+(768) 691 44 85|
|20181219130723_0_12|9168453994|Lynell Riojas |+(695) 918 33 16|
|20181219130723_0_15|4225784815|Jene Mackinnon |+(540) 937 33 71|
|20181219130723_0_15|4225784815|Timika Concannon |+(122) 216 11 25|
|20181219130723_0_15|4225784815|Jene Godfrey |+(285) 643 50 47|
|20181219130723_0_15|4225784815|Gabriele Winburn |+(489) 644 53 67|
+-------------------+----------+-------------------+----------------+
```
Let's now join these tables.
##### Joined datasets
The join statement in Spark:
```scala
val dfJoined = dfCompanies.join(dfContacts, "Seg_Id0")
```
The joined data looks like this:
```
dfJoined.show(13, truncate = false)
+--------------------+----------+-------------+-------------------------+--------+----------+--------------------+----------------+
|Seg_Id0 |COMPANY_ID|COMPANY_NAME |ADDRESS |TAXPAYER|COMPANY_ID|CONTACT_PERSON |PHONE_NUMBER |
+--------------------+----------+-------------+-------------------------+--------+----------+--------------------+----------------+
|20181219130723_0_0 |9377942526|Joan Q & Z |10 Sandton, Johannesburg |92714306|9377942526|Janiece Newcombe |+(277) 944 44 55|
|20181219131239_0_2 |3483483977|Robotrd Inc. |2 Park ave., Johannesburg|31195396|3483483977|Mindy Celestin |+(848) 832 61 68|
|20181219131239_0_2 |3483483977|Robotrd Inc. |2 Park ave., Johannesburg|31195396|3483483977|Tyesha Debow |+(174) 970 97 54|
|20181219131239_0_2 |3483483977|Robotrd Inc. |2 Park ave., Johannesburg|31195396|3483483977|Mabelle Winburn |+(455) 184 13 39|
|20181219131344_0_8 |9546291887|ZjkLPj |5574, Tokyo |73538919|9546291887|Jene Norgard |+(694) 918 17 44|
|20181219131344_0_8 |9546291887|ZjkLPj |5574, Tokyo |73538919|9546291887|Edyth Deveau |+(907) 101 70 64|
|20181219131344_0_8 |9546291887|ZjkLPj |5574, Tokyo |73538919|9546291887|Carrie Celestin |+(300) 252 33 17|
|20181219131344_0_12 |9168453994|Test Bank |1 Garden str., London |82573513|9168453994|Timika Bourke |+(768) 691 44 85|
|20181219131344_0_12 |9168453994|Test Bank |1 Garden str., London |82573513|9168453994|Lynell Riojas |+(695) 918 33 16|
|20181219131344_0_15 |4225784815|ZjkLPj |5574, Tokyo |96136195|4225784815|Jene Mackinnon |+(540) 937 33 71|
|20181219131344_0_15 |4225784815|ZjkLPj |5574, Tokyo |96136195|4225784815|Timika Concannon |+(122) 216 11 25|
|20181219131344_0_15 |4225784815|ZjkLPj |5574, Tokyo |96136195|4225784815|Jene Godfrey |+(285) 643 50 47|
|20181219131344_0_15 |4225784815|ZjkLPj |5574, Tokyo |96136195|4225784815|Gabriele Winburn |+(489) 644 53 67|
+--------------------+----------+-------------+-------------------------+--------+----------+--------------------+----------------+
```
Again, the full example is available at
`spark-cobol/src/main/scala/za/co/absa/cobrix/spark/cobol/examples/CobolSparkExample2.scala`
## COBOL parser extensions
Some encoding formats are not expressible by the standard copybook spec. Cobrix has extensions to help you decode
fields encoded in this way.
### Loading multiple paths
Loading multiple paths in the standard way is not supported.
```scala
val df = spark
.read
.format("cobol")
.option("copybook_contents", copybook)
.load("/path1", "/paths2")
```
But there is a Cobrix extension that allows you to load multiple paths:
```scala
val df = spark
.read
.format("cobol")
.option("copybook_contents", copybook)
.option("data_paths", "/path1,/paths2")
.load()
```
### Parsing little-endian binary numbers
Cobrix expects all binary numbers to be big-endian. If you have a binary number in the little-endian format, use
`COMP-9` (Cobrix extension) instead of `COMP` or `COMP-5` for the affected fields.
For example, `0x01 0x02` is `1 + 2*256 = 513` in big-endian (`COMP`) and `1*256 + 2 = 258` (`COMP-9`) in little-endian.
```
10 NUM PIC S9(8) COMP. ** Big-endian
10 NUM PIC S9(8) COMP-9. ** Little-endian
```
### Parsing 'unsigned packed' aka Easyextract numbers
Unsigned backed numbers are encoded as BCD (`COMP-3`) without the sign nibble. For example, bytes `0x12 0x34` encode
the number `1234`. As of `2.6.2` Cobrix supports decoding such numbers using an extension. Use `COMP-3U` for unsigned
packed numbers.
The 'COMP-3U' usage
```
10 NUM PIC X(4) COMP-3U.
```
Note that when using `X` 4 refers to the number of bytes the field occupies. Here, the number of digits is 4*2 = 8.
```
10 NUM PIC 9(8) COMP-3U.
```
When using `9` 8 refers to the number of digits the number has. Here, the size of the field in bytes is 8/2 = 4.
```
10 NUM PIC 9(6)V99 COMP-3U.
```
You can have decimals when using COMP-3 as well.
### Flattening schema with GROUPs and OCCURS
Flattening could be helpful when migrating data from mainframe data with fields that have OCCURs (arrays) to a relational
databases that do not support nested arrays.
Cobrix has a method that can flatten the schema automatically given a DataFrame produced by `spark-cobol`.
Spark Scala example:
```scala
val dfFlat = SparkUtils.flattenSchema(df, useShortFieldNames = false)
```
PySpark example
```python
from pyspark.sql import SparkSession, DataFrame, SQLContext
from pyspark.sql.types import StructType, StructField, StringType, IntegerType, ArrayType
from py4j.java_gateway import java_import
schema = StructType([
StructField("id", IntegerType(), True),
StructField("name", StringType(), True),
StructField("subjects", ArrayType(StringType()), True)
])
# Sample data
data = [
(1, "Alice", ["Math", "Science"]),
(2, "Bob", ["History", "Geography"]),
(3, "Charlie", ["English", "Math", "Physics"])
]
# Create a test DataFrame
df = spark.createDataFrame(data, schema)
# Show the Dataframe before flattening
df.show()
# Flatten the schema using Cobrix Scala 'SparkUtils.flattenSchema' method
sc = spark.sparkContext
java_import(sc._gateway.jvm, "za.co.absa.cobrix.spark.cobol.utils.SparkUtils")
dfFlatJvm = spark._jvm.SparkUtils.flattenSchema(df._jdf, False)
dfFlat = DataFrame(dfFlatJvm, SQLContext(sc))
# Show the Dataframe after flattening
dfFlat.show(truncate=False)
dfFlat.printSchema()
```
The output looks like this:
```
# Before flattening
+---+-------+------------------------+
|id |name |subjects |
+---+-------+------------------------+
|1 |Alice |[Math, Science] |
|2 |Bob |[History, Geography] |
|3 |Charlie|[English, Math, Physics]|
+---+-------+------------------------+
# After flattening
+---+-------+----------+----------+----------+
|id |name |subjects_0|subjects_1|subjects_2|
+---+-------+----------+----------+----------+
|1 |Alice |Math |Science |null |
|2 |Bob |History |Geography |null |
|3 |Charlie|English |Math |Physics |
+---+-------+----------+----------+----------+
```
## Summary of all available options
##### File reading options
| Option (usage example) | Description |
|----------------------------------------|:---------------------------------------------------------------------------------------------------------------|
| .option("data_paths", "/path1,/path2") | Allows loading data from multiple unrelated paths on the same filesystem. |
| .option("file_start_offset", "0") | Specifies the number of bytes to skip at the beginning of each file. |
| .option("file_end_offset", "0") | Specifies the number of bytes to skip at the end of each file. |
| .option("record_start_offset", "0") | Specifies the number of bytes to skip at the beginning of each record before applying copybook fields to data. |
| .option("record_end_offset", "0") | Specifies the number of bytes to skip at the end of each record after applying copybook fields to data. |
##### Copybook parsing options
| Option (usage example) | Description |
|--------------------------------------|:-----------------------------------------------------------------------------------------------------------------------------------------------------|
| .option("truncate_comments", "true") | Historically, COBOL parser ignores the first 6 characters and all characters after 72. When this option is `false`, no truncation is performed. |
| .option("comments_lbound", 6) | By default each line starts with a 6 character comment. The exact number of characters can be tuned using this option. |
| .option("comments_ubound", 72) | By default all characters after 72th one of each line is ignored by the COBOL parser. The exact number of characters can be tuned using this option. |
##### Data parsing options
| Option (usage example) | Description |
|-----------------------------------------------------------|:----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| .option("string_trimming_policy", "both") | Specifies if and how string fields should be trimmed. Available options: `both` (default), `none`, `left`, `right`, `keep_all`. `keep_all` - keeps control characters when decoding ASCII text files |
| .option("display_pic_always_string", "false") | If `true` fields that have `DISPLAY` format will always be converted to `string` type, even if such fields contain numbers, retaining leading and trailing zeros. Cannot be used together with `strict_integral_precision`. |
| .option("ebcdic_code_page", "common") | Specifies a code page for EBCDIC encoding. Currently supported values: `common` (default), `common_extended`, `cp037`, `cp037_extended`, and others (see "Currently supported EBCDIC code pages" section. |
| .option("ebcdic_code_page_class", "full.class.specifier") | Specifies a user provided class for a custom code page to UNICODE conversion. |
| .option("field_code_page:cp825", "field1, field2") | Specifies the code page for selected fields. You can add mo than 1 such option for multiple code page overrides. |
| .option("is_utf16_big_endian", "true") | Specifies if UTF-16 encoded strings (`National` / `PIC N` format) are big-endian (default). |
| .option("floating_point_format", "IBM") | Specifies a floating-point format. Available options: `IBM` (default), `IEEE754`, `IBM_little_endian`, `IEEE754_little_endian`. |
| .option("variable_size_occurs", "false") | If `false` (default) fields that have `OCCURS 0 TO 100 TIMES DEPENDING ON` clauses always have the same size corresponding to the maximum array size (e.g. 100 in this example). If set to `true` the size of the field will shrink for each field that has less actual elements. |
| .option("occurs_mapping", "{\"FIELD\": {\"X\": 1}}") | If specified, as a JSON string, allows for String `DEPENDING ON` fields with a corresponding mapping. |
| .option("strict_sign_overpunching", "true") | If `true` (default), sign overpunching will only be allowed for signed numbers. If `false`, overpunched positive sign will be allowed for unsigned numbers, but negative sign will result in null. |
| .option("improved_null_detection", "true") | If `true`(default), values that contain only 0x0 ror DISPLAY strings and numbers will be considered `null`s instead of empty strings. |
| .option("strict_integral_precision", "true") | If `true`, Cobrix will not generate `short`/`integer`/`long` Spark data types, and always use `decimal(n)` with the exact precision that matches the copybook. Cannot be used together with `display_pic_always_string`. |
| .option("binary_as_hex", "false") | By default fields that have `PIC X` and `USAGE COMP` are converted to `binary` Spark data type. If this option is set to `true`, such fields will be strings in HEX encoding. |
##### Modifier options
| Option (usage example) | Description |
|-----------------------------------------------------|:------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| .option("schema_retention_policy", "collapse_root") | When `collapse_root` (default) the root level record will be removed from the Spark schema. When `keep_original`, the root level GROUP will be present in the Spark schema |
| .option("drop_group_fillers", "false") | If `true`, all GROUP FILLERs will be dropped from the output schema. If `false` (default), such fields will be retained. |
| .option("drop_value_fillers", "false") | If `true` (default), all non-GROUP FILLERs will be dropped from the output schema. If `false`, such fields will be retained. |
| .option("filler_naming_policy", "sequence_numbers") | Filler renaming strategy so that column names are not duplicated. Either `sequence_numbers` (default) or `previous_field_name` can be used. |
| .option("non_terminals", "GROUP1,GROUP2") | Specifies groups to also be added to the schema as string fields. When this option is specified, the reader will add one extra data field after each matching group containing the string data for the group. |
| .option("generate_record_id", false) | Generate autoincremental 'File_Id', 'Record_Id' and 'Record_Byte_Length' fields. This is used for processing record order dependent data. |
| .option("generate_record_bytes", false) | Generate 'Record_Bytes', the binary field that contains raw contents of the original unparsed records. |
| .option("generate_corrupt_fields", false) | Generate `_corrupt_fields` field that contains values of fields Cobrix was unable to decode. |
| .option("with_input_file_name_col", "file_name") | Generates a column containing input file name for each record (Similar to Spark SQL `input_file_name()` function). The column name is specified by the value of the option. This option only works for variable record length files. For fixed record length and ASCII files use `input_file_name()`. |
| .option("metadata", "basic") | Specifies wat kind of metadata to include in the Spark schema: `false`, `basic`(default), or `extended` (PIC, usage, etc). |
| .option("debug", "hex") | If specified, each primitive field will be accompanied by a debug field containing raw bytes from the source file. Possible values: `none` (default), `hex`, `binary`, `string` (ASCII only). The legacy value `true` is supported and will generate debug fields in HEX. |
##### Fixed length record format options (for record_format = F or FB)
| Option (usage example) | Description |
|-----------------------------------|:----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| .option("record_format", "F") | Record format from the [spec](https://www.ibm.com/docs/en/zos/2.3.0?topic=files-selecting-record-formats-non-vsam-data-sets). One of `F` (fixed length, default), `FB` (fixed block), V` (variable length RDW), `VB` (variable block BDW+RDW), `D` (ASCII text). |
| .option("record_length", "100") | Overrides the length of the record (in bypes). Normally, the size is derived from the copybook. But explicitly specifying record size can be helpful for debugging fixed-record length files. |
| .option("block_length", "500") | Specifies the block length for FB records. It should be a multiple of 'record_length'. Cannot be used together with `records_per_block` |
| .option("records_per_block", "5") | Specifies the number of records ber block for FB records. Cannot be used together with `block_length` |
##### Variable record length files options (for record_format = V or VB)
| Option (usage example) | Description |
|-------------------------------------------------------------|:----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| .option("record_format", "V") | Record format from the [spec](https://www.ibm.com/docs/en/zos/2.3.0?topic=files-selecting-record-formats-non-vsam-data-sets). One of `F` (fixed length, default), `FB` (fixed block), V` (variable length RDW), `VB` (variable block BDW+RDW), `D` (ASCII text). |
| .option("is_record_sequence", "true") | _[deprecated]_ If 'true' the parser will look for 4 byte RDW headers to read variable record length files. Use `.option("record_format", "V")` instead. |
| .option("is_rdw_big_endian", "true") | Specifies if RDW headers are big endian. They are considered little-endian by default. |
| .option("is_rdw_part_of_record_length", false) | Specifies if RDW headers count themselves as part of record length. By default RDW headers count only payload record in record length, not RDW headers themselves. This is equivalent to `.option("rdw_adjustment", -4)`. For BDW use `.option("bdw_adjustment", -4)` |
| .option("rdw_adjustment", 0) | If there is a mismatch between RDW and record length this option can be used to adjust the difference. |
| .option("bdw_adjustment", 0) | If there is a mismatch between BDW and record length this option can be used to adjust the difference. |
| .option("re_additional_info", "") | Passes a string as an additional info parameter passed to a custom record extractor to its constructor. |
| .option("record_length_field", "RECORD-LEN") | Specifies a record length field or expression to use instead of RDW. Use `rdw_adjustment` option if the record length field differs from the actual length by a fixed amount of bytes. The `record_format` should be set to `F`. This option is incompatible with `is_record_sequence`. |
| .option("record_length_map", """{"A":100,"B":50}""") | Specifies a mapping between record length field values and actual record lengths. |
| .option("record_extractor", "com.example.record.extractor") | Specifies a class for parsing record in a custom way. The class must inherit `RawRecordExtractor` and `Serializable` traits. See the chapter on record extractors above. |
| .option("minimum_record_length", 1) | Specifies the minimum length a record is considered valid, will be skipped otherwise. |
| .option("maximum_record_length", 1000) | Specifies the maximum length a record is considered valid, will be skipped otherwise. |
##### ASCII files options (for record_format = D or D2)
| Option (usage example) | Description |
|----------------------------------------------------|:--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| .option("record_format", "D") | Record format from the [spec](https://www.ibm.com/docs/en/zos/2.3.0?topic=files-selecting-record-formats-non-vsam-data-sets). One of `F` (fixed length, default), `FB` (fixed block), V` (variable length RDW), `VB` (variable block BDW+RDW), `D` (ASCII text). |
| .option("is_text", "true") | If 'true' the file will be considered a text file where records are separated by an end-of-line character. Currently, only ASCII files having UTF-8 charset can be processed this way. If combined with `record_format = D`, multisegment and hierarchical text record files can be loaded. |
| .option("ascii_charset", "US-ASCII") | Specifies a charset to use to decode ASCII data. The value can be any charset supported by `java.nio.charset`: `US-ASCII` (default), `UTF-8`, `ISO-8859-1`, etc. |
| .option("field_code_page:cp825", "field1, field2") | Specifies the code page for selected fields. You can add more than 1 such option for multiple code page overrides. |
| .option("minimum_record_length", 1) | Specifies the minimum length a record is considered valid, will be skipped otherwise. It is used to skip ASCII lines that contains invalid records, an EOF character, for example. |
##### Multisegment files options
| Option (usage example) | Description |
|---------------------------------------------------------------------------------------|:-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| .option("segment_field", "SEG-ID") | Specify a segment id field name. This is to ensure the splitting is done using root record boundaries for hierarchical datasets. The first record will be considered a root segment record. |
| .option("redefine-segment-id-map:0", "REDEFINED_FIELD1 => SegmentId1,SegmentId2,...") | Specifies a mapping between redefined field names and segment id values. Each option specifies a mapping for a single segment. The numeric value for each mapping option must be incremented so the option keys are unique. |
| .option("segment-children:0", "COMPANY => EMPLOYEE,DEPARTMENT") | Specifies a mapping between segment redefined fields and their children. Each option specifies a mapping for a single parent field. The numeric value for each mapping option must be incremented so the option keys are unique. If such mapping is specified hierarchical record structure will be automatically reconstructed. This require `redefine-segment-id-map` to be set. |
| .option("enable_indexes", "true") | Turns on indexing of multisegment variable length files (on by default). |
| .option("enable_index_cache", "true") | When true (default), calculated indexes are cached in memory for later use. This improves performance of processing when same files are processed more than once. |
| .option("input_split_records", 50000) | Specifies how many records will be allocated to each split/partition. It will be processed by Spark tasks. (The default is not set and the split will happen according to size, see the next option) |
| .option("input_split_size_mb", 100) | Specify how many megabytes to allocate to each partition/split. (The default is 100 MB) |
##### Helper fields generation options
| Option (usage example) | Description |
|--------------------------------------------|:------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| .option("segment_field", "SEG-ID") | Specified the field in the copybook containing values of segment ids. |
| .option("segment_filter", "S0001") | Allows to add a filter on the segment id that will be pushed down the reader. This is if the intent is to extract records only of a particular segments. |
| .option("segment_id_level0", "SEGID-ROOT") | Specifies segment id value for root level records. When this option is specified the Seg_Id0 field will be generated for each root record |
| .option("segment_id_level1", "SEGID-CLD1") | Specifies segment id value for child level records. When this option is specified the Seg_Id1 field will be generated for each root record |
| .option("segment_id_level2", "SEGID-CLD2") | Specifies segment id value for child of a child level records. When this option is specified the Seg_Id2 field will be generated for each root record. You can use levels 3, 4 etc. |
| .option("segment_id_prefix", "A_PREEFIX") | Specifies a prefix to be added to each segment id value. This is to mage generated IDs globally unique. By default the prefix is the current timestamp in form of '201811122345_'. |
##### Debug helper options
| Option (usage example) | Description |
|----------------------------------------------------|:------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| .option("pedantic", "false") | If 'true' Cobrix will throw an exception is an unknown option is encountered. If 'false' (default), unknown options will be logged as an error without failing Spark Application. |
| .option("debug_layout_positions", "true") | If 'true' Cobrix will generate and log layout positions table when reading data. |
| .option("debug_ignore_file_size", "true") | If 'true' no exception will be thrown if record size does not match file size. Useful for debugging copybooks to make them match a data file. |
| .option("enable_self_checks", "true") | If 'true' Cobrix will run self-checks to validate internal consistency. Note: Enabling this option may impact performance, especially for large datasets. It is recommended to disable this option in performance-critical environments. The only check implemented so far is custom record extractor indexing compatibility check. |
##### Currently supported EBCDIC code pages
| Option | Code page | Description |
|:--------------------------------------|-------------|:------------------------------------------------------------------------------------------------------------|
| .option("ebcdic_code_page", "common") | Common | (Default) Only characters common across EBCDIC code pages are decoded. |
| .option("ebcdic_code_page", "cp037") | EBCDIC 037 | Australia, Brazil, Canada, New Zealand, Portugal, South Africa, USA. |
| .option("ebcdic_code_page", "cp273") | EBCDIC 273 | Germany, Austria. |
| .option("ebcdic_code_page", "cp274") | EBCDIC 274 | Belgium. |
| .option("ebcdic_code_page", "cp275") | EBCDIC 275 | Brazil. |
| .option("ebcdic_code_page", "cp277") | EBCDIC 277 | Denmark and Norway. |
| .option("ebcdic_code_page", "cp278") | EBCDIC 278 | Finland and Sweden. |
| .option("ebcdic_code_page", "cp280") | EBCDIC 280 | Italy. |
| .option("ebcdic_code_page", "cp284") | EBCDIC 284 | Spain and Latin America. |
| .option("ebcdic_code_page", "cp285") | EBCDIC 285 | United Kingdom. |
| .option("ebcdic_code_page", "cp297") | EBCDIC 297 | France. |
| .option("ebcdic_code_page", "cp300") | EBCDIC 300 | Double-byte code page with Japanese and Latin characters. |
| .option("ebcdic_code_page", "cp500") | EBCDIC 500 | Belgium, Canada, Switzerland, International. |
| .option("ebcdic_code_page", "cp838") | EBCDIC 838 | Double-byte code page with Thai and Latin characters. |
| .option("ebcdic_code_page", "cp870") | EBCDIC 870 | Albania, Bosnia and Herzegovina, Croatia, Czech Republic, Hungary, Poland, Romania, Slovakia, and Slovenia. |
| .option("ebcdic_code_page", "cp875") | EBCDIC 875 | A code page with Greek characters. |
| .option("ebcdic_code_page", "cp1025") | EBCDIC 1025 | A code page with Cyrillic alphabet. |
| .option("ebcdic_code_page", "cp1047") | EBCDIC 1047 | A code page containing all of the Latin-1/Open System characters. |
| .option("ebcdic_code_page", "cp1140") | EBCDIC 1140 | Same as code page 037 with € at the position of the international currency symbol ¤. |