lua-rocksdb

Lua binding for RocksDB

Installation

• Install RocksDB (make shared_lib, make static_lib), download from: https://github.com/facebook/rocksdb
• Update the Makefile if needed to point at the correct include/lib paths

Example

  local rocksdb = require("rocksdb")
  local options = rocksdb.options({
    create_if_missing = true
  })
  local db = rocksdb.open(options, "/tmp/test.rocksdb")
  local writeoptions = rocksdb.writeoptions()
  local readoptions = rocksdb.readoptions()
  db:put(writeoptions, "key", "value")
  print(db:get(readoptions, "key"))
  db:close()

Doc

rocksdb.options()

Creates an options object, the options are passed as a table. Currently only basic types (bool, int, uint64) types are supported.

rocksdb.readoptions()

Creates a readoptions object.

rocksdb.writeoptions()

Create a writeoptions object.

rocksdb.restoreoptions(table)

Create a restoreoptions object.

• table options map, supported:
  • keep_log_files - number of log files to keep

rocksdb.open(options, db_path)

• options - object (created using rocksdb.options())
• db_path - string. path
• returns rocksdb object (referenced below as db)

db:put(writeoptions, key, value)

Execute a put command, key-value (both of string type).

• writeoptions - write options object (created using rocksdb.writeoptions())
• key - string
• value - string

rocksdb:get(readoptions, key)

Gets a value from the DB.

• readoptions - read options object (created using rocksdb.readoptions())
• key - string

rocksdb:write(writeoptions, writebatch)

Executes write operation on a batch.

• writeoptions - created using rocksdb.writeoptions()
• writebatch - created using rocksdb.writebatch()

rocksdb:iterator(readoptions)

Returns an iterator object.

rocksdb:close()

Closes the instance (it doesn't destroy the DB!)

rocksdb.backup_engine(options, backup_path)

Creates a backup engine object.

• options options object (created using rocksdb.options())
• backup_path - string - backup path
• returns backup_engine object

backup_engine:create_new_backup(db)

Creates a back from db.

• db db object (rocksdb.open())
• returns true on success, error on failure

backup_engine:purge_old_backups(number)

Purge number of old backups.

backup_engine:get_backup_info_count()

Returns the number of the available backups.

backup_engine:get_backup_info(index)

Returns info of a backup at index (note indices start at 1, to keep with Lua 1-based array).

• returns table

keys

• id
• timestamp
• size
• number_files

backup_engine:restore_db_from_latest_backup(db_path, wal_dir, restoreoptions)

Restores DB from the latest backup.

• db_path (string)
• wal_dir (string)
• restoreoptions (created using rocksdb.restoreoptions()) Returns an error on failure

backup_engine:close()

Close/free the backup_engine instance

rocksdb.writebatch()

Creates a writebatch instance.

writebatch:put(key, value)

Puts a key with its value into the batch (both are strings).

writebatch:count()

Returns the count of key-values pairs in the batch.

writebatch:clear()

Clears the writebatch.

writebatch:destroy()

Frees the writebatch instance.

iterator:valid()

Returns true if the iterator is valid, false otherwise.

iterator:seek_to_first(), iterator:seek_to_last()

Seek to first/last iterm.

iterator:seek(key)

Seek specific key.

iterator:next(), iterator:prev()

Move to next/prev item.

iterator:key(), iterator:value()

Returns string key/value.

iterator:get_error()

Returns string error message of the iterator.

iterator:destroy()

Frees the iterator instance.