https://github.com/colinmarc/cdb

A native golang implementation of cdb (http://cr.yp.to/cdb.html)
https://github.com/colinmarc/cdb

Last synced: about 3 hours ago
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A native golang implementation of cdb (http://cr.yp.to/cdb.html)

• Host: GitHub
• URL: https://github.com/colinmarc/cdb
• Owner: colinmarc
• License: mit
• Created: 2015-08-29T17:33:36.000Z (about 9 years ago)
• Default Branch: master
• Last Pushed: 2019-02-23T17:12:19.000Z (over 5 years ago)
• Last Synced: 2024-10-31T15:53:01.287Z (7 days ago)
• Language: Go
• Homepage:
• Size: 22.5 KB
• Stars: 65
• Watchers: 10
• Forks: 13
• Open Issues: 4
• Metadata Files:
  • Readme: README.md
  • License: LICENSE.txt

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CDB

===

[![GoDoc](https://godoc.org/github.com/colinmarc/cdb/web?status.svg)](https://godoc.org/github.com/colinmarc/cdb) [![build](https://travis-ci.org/colinmarc/cdb.svg?branch=master)](https://travis-ci.org/colinmarc/hdfs)

This is a native Go implementation of [cdb][1], a constant key/value database

with some very nice properties. From the [design doc][1]:

> cdb is a fast, reliable, simple package for creating and reading constant databases. Its database structure provides several features:

> - Fast lookups: A successful lookup in a large database normally takes just two disk accesses. An unsuccessful lookup takes only one.

> - Low overhead: A database uses 2048 bytes, plus 24 bytes per record, plus the space for keys and data.

> - No random limits: cdb can handle any database up to 4 gigabytes. There are no other restrictions; records don't even have to fit into memory. Databases are stored in a machine-independent format.

[1]: http://cr.yp.to/cdb.html

Usage

-----

```go

writer, err := cdb.Create("/tmp/example.cdb")

if err != nil {

  log.Fatal(err)

}

// Write some key/value pairs to the database.

writer.Put([]byte("Alice"), []byte("Practice"))

writer.Put([]byte("Bob"), []byte("Hope"))

writer.Put([]byte("Charlie"), []byte("Horse"))

// Freeze the database, and open it for reads.

db, err := writer.Freeze()

if err != nil {

  log.Fatal(err)

}

// Fetch a value.

v, err := db.Get([]byte("Alice"))

if err != nil {

  log.Fatal(err)

}

log.Println(string(v))

// => Practice

// Iterate over the database

iter := db.Iter()

for iter.Next() {

    log.Printf("The key %s has a value of length %d\n", string(iter.Key()), len(iter.Value()))

}

if err := iter.Err(); err != nil {

    log.Fatal(err)

}

```