diff options
Diffstat (limited to 'vendor/github.com/syndtr/goleveldb/leveldb/opt')
-rw-r--r-- | vendor/github.com/syndtr/goleveldb/leveldb/opt/options.go | 684 |
1 files changed, 684 insertions, 0 deletions
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/opt/options.go b/vendor/github.com/syndtr/goleveldb/leveldb/opt/options.go new file mode 100644 index 000000000..44e7d9adc --- /dev/null +++ b/vendor/github.com/syndtr/goleveldb/leveldb/opt/options.go @@ -0,0 +1,684 @@ +// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com> +// All rights reserved. +// +// Use of this source code is governed by a BSD-style license that can be +// found in the LICENSE file. + +// Package opt provides sets of options used by LevelDB. +package opt + +import ( + "math" + + "github.com/syndtr/goleveldb/leveldb/cache" + "github.com/syndtr/goleveldb/leveldb/comparer" + "github.com/syndtr/goleveldb/leveldb/filter" +) + +const ( + KiB = 1024 + MiB = KiB * 1024 + GiB = MiB * 1024 +) + +var ( + DefaultBlockCacher = LRUCacher + DefaultBlockCacheCapacity = 8 * MiB + DefaultBlockRestartInterval = 16 + DefaultBlockSize = 4 * KiB + DefaultCompactionExpandLimitFactor = 25 + DefaultCompactionGPOverlapsFactor = 10 + DefaultCompactionL0Trigger = 4 + DefaultCompactionSourceLimitFactor = 1 + DefaultCompactionTableSize = 2 * MiB + DefaultCompactionTableSizeMultiplier = 1.0 + DefaultCompactionTotalSize = 10 * MiB + DefaultCompactionTotalSizeMultiplier = 10.0 + DefaultCompressionType = SnappyCompression + DefaultIteratorSamplingRate = 1 * MiB + DefaultOpenFilesCacher = LRUCacher + DefaultOpenFilesCacheCapacity = 500 + DefaultWriteBuffer = 4 * MiB + DefaultWriteL0PauseTrigger = 12 + DefaultWriteL0SlowdownTrigger = 8 +) + +// Cacher is a caching algorithm. +type Cacher interface { + New(capacity int) cache.Cacher +} + +type CacherFunc struct { + NewFunc func(capacity int) cache.Cacher +} + +func (f *CacherFunc) New(capacity int) cache.Cacher { + if f.NewFunc != nil { + return f.NewFunc(capacity) + } + return nil +} + +func noCacher(int) cache.Cacher { return nil } + +var ( + // LRUCacher is the LRU-cache algorithm. + LRUCacher = &CacherFunc{cache.NewLRU} + + // NoCacher is the value to disable caching algorithm. + NoCacher = &CacherFunc{} +) + +// Compression is the 'sorted table' block compression algorithm to use. +type Compression uint + +func (c Compression) String() string { + switch c { + case DefaultCompression: + return "default" + case NoCompression: + return "none" + case SnappyCompression: + return "snappy" + } + return "invalid" +} + +const ( + DefaultCompression Compression = iota + NoCompression + SnappyCompression + nCompression +) + +// Strict is the DB 'strict level'. +type Strict uint + +const ( + // If present then a corrupted or invalid chunk or block in manifest + // journal will cause an error instead of being dropped. + // This will prevent database with corrupted manifest to be opened. + StrictManifest Strict = 1 << iota + + // If present then journal chunk checksum will be verified. + StrictJournalChecksum + + // If present then a corrupted or invalid chunk or block in journal + // will cause an error instead of being dropped. + // This will prevent database with corrupted journal to be opened. + StrictJournal + + // If present then 'sorted table' block checksum will be verified. + // This has effect on both 'read operation' and compaction. + StrictBlockChecksum + + // If present then a corrupted 'sorted table' will fails compaction. + // The database will enter read-only mode. + StrictCompaction + + // If present then a corrupted 'sorted table' will halts 'read operation'. + StrictReader + + // If present then leveldb.Recover will drop corrupted 'sorted table'. + StrictRecovery + + // This only applicable for ReadOptions, if present then this ReadOptions + // 'strict level' will override global ones. + StrictOverride + + // StrictAll enables all strict flags. + StrictAll = StrictManifest | StrictJournalChecksum | StrictJournal | StrictBlockChecksum | StrictCompaction | StrictReader | StrictRecovery + + // DefaultStrict is the default strict flags. Specify any strict flags + // will override default strict flags as whole (i.e. not OR'ed). + DefaultStrict = StrictJournalChecksum | StrictBlockChecksum | StrictCompaction | StrictReader + + // NoStrict disables all strict flags. Override default strict flags. + NoStrict = ^StrictAll +) + +// Options holds the optional parameters for the DB at large. +type Options struct { + // AltFilters defines one or more 'alternative filters'. + // 'alternative filters' will be used during reads if a filter block + // does not match with the 'effective filter'. + // + // The default value is nil + AltFilters []filter.Filter + + // BlockCacher provides cache algorithm for LevelDB 'sorted table' block caching. + // Specify NoCacher to disable caching algorithm. + // + // The default value is LRUCacher. + BlockCacher Cacher + + // BlockCacheCapacity defines the capacity of the 'sorted table' block caching. + // Use -1 for zero, this has same effect as specifying NoCacher to BlockCacher. + // + // The default value is 8MiB. + BlockCacheCapacity int + + // BlockRestartInterval is the number of keys between restart points for + // delta encoding of keys. + // + // The default value is 16. + BlockRestartInterval int + + // BlockSize is the minimum uncompressed size in bytes of each 'sorted table' + // block. + // + // The default value is 4KiB. + BlockSize int + + // CompactionExpandLimitFactor limits compaction size after expanded. + // This will be multiplied by table size limit at compaction target level. + // + // The default value is 25. + CompactionExpandLimitFactor int + + // CompactionGPOverlapsFactor limits overlaps in grandparent (Level + 2) that a + // single 'sorted table' generates. + // This will be multiplied by table size limit at grandparent level. + // + // The default value is 10. + CompactionGPOverlapsFactor int + + // CompactionL0Trigger defines number of 'sorted table' at level-0 that will + // trigger compaction. + // + // The default value is 4. + CompactionL0Trigger int + + // CompactionSourceLimitFactor limits compaction source size. This doesn't apply to + // level-0. + // This will be multiplied by table size limit at compaction target level. + // + // The default value is 1. + CompactionSourceLimitFactor int + + // CompactionTableSize limits size of 'sorted table' that compaction generates. + // The limits for each level will be calculated as: + // CompactionTableSize * (CompactionTableSizeMultiplier ^ Level) + // The multiplier for each level can also fine-tuned using CompactionTableSizeMultiplierPerLevel. + // + // The default value is 2MiB. + CompactionTableSize int + + // CompactionTableSizeMultiplier defines multiplier for CompactionTableSize. + // + // The default value is 1. + CompactionTableSizeMultiplier float64 + + // CompactionTableSizeMultiplierPerLevel defines per-level multiplier for + // CompactionTableSize. + // Use zero to skip a level. + // + // The default value is nil. + CompactionTableSizeMultiplierPerLevel []float64 + + // CompactionTotalSize limits total size of 'sorted table' for each level. + // The limits for each level will be calculated as: + // CompactionTotalSize * (CompactionTotalSizeMultiplier ^ Level) + // The multiplier for each level can also fine-tuned using + // CompactionTotalSizeMultiplierPerLevel. + // + // The default value is 10MiB. + CompactionTotalSize int + + // CompactionTotalSizeMultiplier defines multiplier for CompactionTotalSize. + // + // The default value is 10. + CompactionTotalSizeMultiplier float64 + + // CompactionTotalSizeMultiplierPerLevel defines per-level multiplier for + // CompactionTotalSize. + // Use zero to skip a level. + // + // The default value is nil. + CompactionTotalSizeMultiplierPerLevel []float64 + + // Comparer defines a total ordering over the space of []byte keys: a 'less + // than' relationship. The same comparison algorithm must be used for reads + // and writes over the lifetime of the DB. + // + // The default value uses the same ordering as bytes.Compare. + Comparer comparer.Comparer + + // Compression defines the 'sorted table' block compression to use. + // + // The default value (DefaultCompression) uses snappy compression. + Compression Compression + + // DisableBufferPool allows disable use of util.BufferPool functionality. + // + // The default value is false. + DisableBufferPool bool + + // DisableBlockCache allows disable use of cache.Cache functionality on + // 'sorted table' block. + // + // The default value is false. + DisableBlockCache bool + + // DisableCompactionBackoff allows disable compaction retry backoff. + // + // The default value is false. + DisableCompactionBackoff bool + + // DisableLargeBatchTransaction allows disabling switch-to-transaction mode + // on large batch write. If enable batch writes large than WriteBuffer will + // use transaction. + // + // The default is false. + DisableLargeBatchTransaction bool + + // ErrorIfExist defines whether an error should returned if the DB already + // exist. + // + // The default value is false. + ErrorIfExist bool + + // ErrorIfMissing defines whether an error should returned if the DB is + // missing. If false then the database will be created if missing, otherwise + // an error will be returned. + // + // The default value is false. + ErrorIfMissing bool + + // Filter defines an 'effective filter' to use. An 'effective filter' + // if defined will be used to generate per-table filter block. + // The filter name will be stored on disk. + // During reads LevelDB will try to find matching filter from + // 'effective filter' and 'alternative filters'. + // + // Filter can be changed after a DB has been created. It is recommended + // to put old filter to the 'alternative filters' to mitigate lack of + // filter during transition period. + // + // A filter is used to reduce disk reads when looking for a specific key. + // + // The default value is nil. + Filter filter.Filter + + // IteratorSamplingRate defines approximate gap (in bytes) between read + // sampling of an iterator. The samples will be used to determine when + // compaction should be triggered. + // + // The default is 1MiB. + IteratorSamplingRate int + + // NoSync allows completely disable fsync. + // + // The default is false. + NoSync bool + + // NoWriteMerge allows disabling write merge. + // + // The default is false. + NoWriteMerge bool + + // OpenFilesCacher provides cache algorithm for open files caching. + // Specify NoCacher to disable caching algorithm. + // + // The default value is LRUCacher. + OpenFilesCacher Cacher + + // OpenFilesCacheCapacity defines the capacity of the open files caching. + // Use -1 for zero, this has same effect as specifying NoCacher to OpenFilesCacher. + // + // The default value is 500. + OpenFilesCacheCapacity int + + // If true then opens DB in read-only mode. + // + // The default value is false. + ReadOnly bool + + // Strict defines the DB strict level. + Strict Strict + + // WriteBuffer defines maximum size of a 'memdb' before flushed to + // 'sorted table'. 'memdb' is an in-memory DB backed by an on-disk + // unsorted journal. + // + // LevelDB may held up to two 'memdb' at the same time. + // + // The default value is 4MiB. + WriteBuffer int + + // WriteL0StopTrigger defines number of 'sorted table' at level-0 that will + // pause write. + // + // The default value is 12. + WriteL0PauseTrigger int + + // WriteL0SlowdownTrigger defines number of 'sorted table' at level-0 that + // will trigger write slowdown. + // + // The default value is 8. + WriteL0SlowdownTrigger int +} + +func (o *Options) GetAltFilters() []filter.Filter { + if o == nil { + return nil + } + return o.AltFilters +} + +func (o *Options) GetBlockCacher() Cacher { + if o == nil || o.BlockCacher == nil { + return DefaultBlockCacher + } else if o.BlockCacher == NoCacher { + return nil + } + return o.BlockCacher +} + +func (o *Options) GetBlockCacheCapacity() int { + if o == nil || o.BlockCacheCapacity == 0 { + return DefaultBlockCacheCapacity + } else if o.BlockCacheCapacity < 0 { + return 0 + } + return o.BlockCacheCapacity +} + +func (o *Options) GetBlockRestartInterval() int { + if o == nil || o.BlockRestartInterval <= 0 { + return DefaultBlockRestartInterval + } + return o.BlockRestartInterval +} + +func (o *Options) GetBlockSize() int { + if o == nil || o.BlockSize <= 0 { + return DefaultBlockSize + } + return o.BlockSize +} + +func (o *Options) GetCompactionExpandLimit(level int) int { + factor := DefaultCompactionExpandLimitFactor + if o != nil && o.CompactionExpandLimitFactor > 0 { + factor = o.CompactionExpandLimitFactor + } + return o.GetCompactionTableSize(level+1) * factor +} + +func (o *Options) GetCompactionGPOverlaps(level int) int { + factor := DefaultCompactionGPOverlapsFactor + if o != nil && o.CompactionGPOverlapsFactor > 0 { + factor = o.CompactionGPOverlapsFactor + } + return o.GetCompactionTableSize(level+2) * factor +} + +func (o *Options) GetCompactionL0Trigger() int { + if o == nil || o.CompactionL0Trigger == 0 { + return DefaultCompactionL0Trigger + } + return o.CompactionL0Trigger +} + +func (o *Options) GetCompactionSourceLimit(level int) int { + factor := DefaultCompactionSourceLimitFactor + if o != nil && o.CompactionSourceLimitFactor > 0 { + factor = o.CompactionSourceLimitFactor + } + return o.GetCompactionTableSize(level+1) * factor +} + +func (o *Options) GetCompactionTableSize(level int) int { + var ( + base = DefaultCompactionTableSize + mult float64 + ) + if o != nil { + if o.CompactionTableSize > 0 { + base = o.CompactionTableSize + } + if level < len(o.CompactionTableSizeMultiplierPerLevel) && o.CompactionTableSizeMultiplierPerLevel[level] > 0 { + mult = o.CompactionTableSizeMultiplierPerLevel[level] + } else if o.CompactionTableSizeMultiplier > 0 { + mult = math.Pow(o.CompactionTableSizeMultiplier, float64(level)) + } + } + if mult == 0 { + mult = math.Pow(DefaultCompactionTableSizeMultiplier, float64(level)) + } + return int(float64(base) * mult) +} + +func (o *Options) GetCompactionTotalSize(level int) int64 { + var ( + base = DefaultCompactionTotalSize + mult float64 + ) + if o != nil { + if o.CompactionTotalSize > 0 { + base = o.CompactionTotalSize + } + if level < len(o.CompactionTotalSizeMultiplierPerLevel) && o.CompactionTotalSizeMultiplierPerLevel[level] > 0 { + mult = o.CompactionTotalSizeMultiplierPerLevel[level] + } else if o.CompactionTotalSizeMultiplier > 0 { + mult = math.Pow(o.CompactionTotalSizeMultiplier, float64(level)) + } + } + if mult == 0 { + mult = math.Pow(DefaultCompactionTotalSizeMultiplier, float64(level)) + } + return int64(float64(base) * mult) +} + +func (o *Options) GetComparer() comparer.Comparer { + if o == nil || o.Comparer == nil { + return comparer.DefaultComparer + } + return o.Comparer +} + +func (o *Options) GetCompression() Compression { + if o == nil || o.Compression <= DefaultCompression || o.Compression >= nCompression { + return DefaultCompressionType + } + return o.Compression +} + +func (o *Options) GetDisableBufferPool() bool { + if o == nil { + return false + } + return o.DisableBufferPool +} + +func (o *Options) GetDisableBlockCache() bool { + if o == nil { + return false + } + return o.DisableBlockCache +} + +func (o *Options) GetDisableCompactionBackoff() bool { + if o == nil { + return false + } + return o.DisableCompactionBackoff +} + +func (o *Options) GetDisableLargeBatchTransaction() bool { + if o == nil { + return false + } + return o.DisableLargeBatchTransaction +} + +func (o *Options) GetErrorIfExist() bool { + if o == nil { + return false + } + return o.ErrorIfExist +} + +func (o *Options) GetErrorIfMissing() bool { + if o == nil { + return false + } + return o.ErrorIfMissing +} + +func (o *Options) GetFilter() filter.Filter { + if o == nil { + return nil + } + return o.Filter +} + +func (o *Options) GetIteratorSamplingRate() int { + if o == nil || o.IteratorSamplingRate <= 0 { + return DefaultIteratorSamplingRate + } + return o.IteratorSamplingRate +} + +func (o *Options) GetNoSync() bool { + if o == nil { + return false + } + return o.NoSync +} + +func (o *Options) GetNoWriteMerge() bool { + if o == nil { + return false + } + return o.NoWriteMerge +} + +func (o *Options) GetOpenFilesCacher() Cacher { + if o == nil || o.OpenFilesCacher == nil { + return DefaultOpenFilesCacher + } + if o.OpenFilesCacher == NoCacher { + return nil + } + return o.OpenFilesCacher +} + +func (o *Options) GetOpenFilesCacheCapacity() int { + if o == nil || o.OpenFilesCacheCapacity == 0 { + return DefaultOpenFilesCacheCapacity + } else if o.OpenFilesCacheCapacity < 0 { + return 0 + } + return o.OpenFilesCacheCapacity +} + +func (o *Options) GetReadOnly() bool { + if o == nil { + return false + } + return o.ReadOnly +} + +func (o *Options) GetStrict(strict Strict) bool { + if o == nil || o.Strict == 0 { + return DefaultStrict&strict != 0 + } + return o.Strict&strict != 0 +} + +func (o *Options) GetWriteBuffer() int { + if o == nil || o.WriteBuffer <= 0 { + return DefaultWriteBuffer + } + return o.WriteBuffer +} + +func (o *Options) GetWriteL0PauseTrigger() int { + if o == nil || o.WriteL0PauseTrigger == 0 { + return DefaultWriteL0PauseTrigger + } + return o.WriteL0PauseTrigger +} + +func (o *Options) GetWriteL0SlowdownTrigger() int { + if o == nil || o.WriteL0SlowdownTrigger == 0 { + return DefaultWriteL0SlowdownTrigger + } + return o.WriteL0SlowdownTrigger +} + +// ReadOptions holds the optional parameters for 'read operation'. The +// 'read operation' includes Get, Find and NewIterator. +type ReadOptions struct { + // DontFillCache defines whether block reads for this 'read operation' + // should be cached. If false then the block will be cached. This does + // not affects already cached block. + // + // The default value is false. + DontFillCache bool + + // Strict will be OR'ed with global DB 'strict level' unless StrictOverride + // is present. Currently only StrictReader that has effect here. + Strict Strict +} + +func (ro *ReadOptions) GetDontFillCache() bool { + if ro == nil { + return false + } + return ro.DontFillCache +} + +func (ro *ReadOptions) GetStrict(strict Strict) bool { + if ro == nil { + return false + } + return ro.Strict&strict != 0 +} + +// WriteOptions holds the optional parameters for 'write operation'. The +// 'write operation' includes Write, Put and Delete. +type WriteOptions struct { + // NoWriteMerge allows disabling write merge. + // + // The default is false. + NoWriteMerge bool + + // Sync is whether to sync underlying writes from the OS buffer cache + // through to actual disk, if applicable. Setting Sync can result in + // slower writes. + // + // If false, and the machine crashes, then some recent writes may be lost. + // Note that if it is just the process that crashes (and the machine does + // not) then no writes will be lost. + // + // In other words, Sync being false has the same semantics as a write + // system call. Sync being true means write followed by fsync. + // + // The default value is false. + Sync bool +} + +func (wo *WriteOptions) GetNoWriteMerge() bool { + if wo == nil { + return false + } + return wo.NoWriteMerge +} + +func (wo *WriteOptions) GetSync() bool { + if wo == nil { + return false + } + return wo.Sync +} + +func GetStrict(o *Options, ro *ReadOptions, strict Strict) bool { + if ro.GetStrict(StrictOverride) { + return ro.GetStrict(strict) + } else { + return o.GetStrict(strict) || ro.GetStrict(strict) + } +} |