https://github.com/base/goleveldb
https://github.com/base/goleveldb
Last synced: 4 months ago
JSON representation
- Host: GitHub
- URL: https://github.com/base/goleveldb
- Owner: base
- License: bsd-2-clause
- Created: 2025-03-07T03:45:54.000Z (over 1 year ago)
- Default Branch: master
- Last Pushed: 2025-04-28T17:14:46.000Z (about 1 year ago)
- Last Synced: 2025-06-17T12:46:41.111Z (about 1 year ago)
- Language: Go
- Size: 1.78 MB
- Stars: 0
- Watchers: 4
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
Fork Notice
-----------
Forked from [github.com/syndtr/goleveldb](https://github.com/syndtr/goleveldb) on 2025-03-10 at commit 2ae1ddf74ef7020251ff1ff0fe8daac21a157761.
This corresponds to the version specified as a dependency by go-ethereum and op-geth when this fork was created (github.com/syndtr/goleveldb v1.0.1-0.20210819022825-2ae1ddf74ef7).
This fork adds support for setting database initialization parameters via environment variables.
Supported environment variables:
| Name | Type | Default Value | Corresponds To |
| --------------------------------------------- | ------- | --------------- | ------------------------------------------- |
| `LDB_BLOCK_SIZE` | Integer | `4096` | `opt.Options.BlockSize` |
| `LDB_COMPACTION_TABLE_SIZE` | Integer | `2097152` | `opt.Options.CompactionTableSize` |
| `LDB_COMPACTION_TOTAL_SIZE` | Integer | `10485760` | `opt.Options.CompactionTotalSize` |
| `LDB_COMPACTION_TOTAL_SIZE_MULTIPLIER` | Integer | `10` | `opt.Options.CompactionTotalSizeMultiplier` |
| `LDB_BLOCK_CACHE_CAPACITY` | Integer | `8388608` | `opt.Options.BlockCacheCapacity` |
| `LDB_BLOCK_RESTART_INTERVAL` | Integer | `16` | `opt.Options.BlockRestartInterval` |
| `LDB_COMPACTION_EXPAND_LIMIT_FACTOR` | Integer | `25` | `opt.Options.CompactionExpandLimitFactor` |
| `LDB_COMPACTION_GP_OVERLAPS_FACTOR` | Integer | `10` | `opt.Options.CompactionGPOverlapsFactor` |
| `LDB_COMPACTION_L0_TRIGGER` | Integer | `4` | `opt.Options.CompactionL0Trigger` |
| `LDB_COMPACTION_SOURCE_LIMIT_FACTOR` | Integer | `1` | `opt.Options.CompactionSourceLimitFactor` |
| `LDB_ITERATOR_SAMPLING_RATE` | Integer | `1048576` | `opt.Options.IteratorSamplingRate` |
| `LDB_WRITE_BUFFER` | Integer | `4194304` | `opt.Options.WriteBuffer` |
| `LDB_WRITE_L0_PAUSE_TRIGGER` | Integer | `12` | `opt.Options.WriteL0PauseTrigger` |
| `LDB_WRITE_L0_SLOWDOWN_TRIGGER` | Integer | `8` | `opt.Options.WriteL0SlowdownTrigger` |
| `LDB_FILTER_BASE_LG` | Integer | `11` | `opt.Options.FilterBaseLg` |
| `LDB_OPEN_FILES_CACHE_CAPACITY` | Integer | `200` (MacOS), `500` (others) | `opt.Options.OpenFilesCacheCapacity` |
| `LDB_DISABLE_COMPRESSION` | Boolean | `false` | `opt.Options.Compression` (if true, set to `opt.NoCompression`) |
| `LDB_NO_SYNC` | Boolean | `false` | `opt.Options.NoSync` |
| `LDB_BLOCK_CACHE_EVICT_REMOVED` | Boolean | `false` | `opt.Options.BlockCacheEvictRemoved` |
| `LDB_DISABLE_BUFFER_POOL` | Boolean | `false` | `opt.Options.DisableBufferPool` |
| `LDB_DISABLE_BLOCK_CACHE` | Boolean | `false` | `opt.Options.DisableBlockCache` |
| `LDB_DISABLE_COMPACTION_BACKOFF` | Boolean | `false` | `opt.Options.DisableCompactionBackoff` |
| `LDB_DISABLE_LARGE_BATCH_TRANSACTION` | Boolean | `false` | `opt.Options.DisableLargeBatchTransaction` |
| `LDB_DISABLE_SEEKS_COMPACTION` | Boolean | `false` | `opt.Options.DisableSeeksCompaction` |
| `LDB_ERROR_IF_EXIST` | Boolean | `false` | `opt.Options.ErrorIfExist` |
| `LDB_ERROR_IF_MISSING` | Boolean | `false` | `opt.Options.ErrorIfMissing` |
| `LDB_NO_WRITE_MERGE` | Boolean | `false` | `opt.Options.NoWriteMerge` |
| `LDB_READ_ONLY` | Boolean | `false` | `opt.Options.ReadOnly` |
| `LDB_DEBUG_OPTIONS` | Boolean | `false` | will print `opt.Options` to the console after initialization |
-----------
This is an implementation of the [LevelDB key/value database](http:code.google.com/p/leveldb) in the [Go programming language](http:golang.org).
Installation
-----------
go get github.com/base/goleveldb/leveldb
Requirements
-----------
* Need at least `go1.5` or newer.
Usage
-----------
Create or open a database:
```go
// The returned DB instance is safe for concurrent use. Which mean that all
// DB's methods may be called concurrently from multiple goroutine.
db, err := leveldb.OpenFile("path/to/db", nil)
...
defer db.Close()
...
```
Read or modify the database content:
```go
// Remember that the contents of the returned slice should not be modified.
data, err := db.Get([]byte("key"), nil)
...
err = db.Put([]byte("key"), []byte("value"), nil)
...
err = db.Delete([]byte("key"), nil)
...
```
Iterate over database content:
```go
iter := db.NewIterator(nil, nil)
for iter.Next() {
// Remember that the contents of the returned slice should not be modified, and
// only valid until the next call to Next.
key := iter.Key()
value := iter.Value()
...
}
iter.Release()
err = iter.Error()
...
```
Seek-then-Iterate:
```go
iter := db.NewIterator(nil, nil)
for ok := iter.Seek(key); ok; ok = iter.Next() {
// Use key/value.
...
}
iter.Release()
err = iter.Error()
...
```
Iterate over subset of database content:
```go
iter := db.NewIterator(&util.Range{Start: []byte("foo"), Limit: []byte("xoo")}, nil)
for iter.Next() {
// Use key/value.
...
}
iter.Release()
err = iter.Error()
...
```
Iterate over subset of database content with a particular prefix:
```go
iter := db.NewIterator(util.BytesPrefix([]byte("foo-")), nil)
for iter.Next() {
// Use key/value.
...
}
iter.Release()
err = iter.Error()
...
```
Batch writes:
```go
batch := new(leveldb.Batch)
batch.Put([]byte("foo"), []byte("value"))
batch.Put([]byte("bar"), []byte("another value"))
batch.Delete([]byte("baz"))
err = db.Write(batch, nil)
...
```
Use bloom filter:
```go
o := &opt.Options{
Filter: filter.NewBloomFilter(10),
}
db, err := leveldb.OpenFile("path/to/db", o)
...
defer db.Close()
...
```