ceremonyclient/pebble/sstable/options.go
Cassandra Heart 2e2a1e4789
v1.2.0 (#31)
2024-01-03 01:31:42 -06:00

306 lines
11 KiB
Go

// Copyright 2019 The LevelDB-Go and Pebble Authors. All rights reserved. Use
// of this source code is governed by a BSD-style license that can be found in
// the LICENSE file.
package sstable
import (
"github.com/cockroachdb/pebble/internal/base"
"github.com/cockroachdb/pebble/internal/cache"
)
// Compression is the per-block compression algorithm to use.
type Compression int
// The available compression types.
const (
DefaultCompression Compression = iota
NoCompression
SnappyCompression
ZstdCompression
NCompression
)
var ignoredInternalProperties = map[string]struct{}{
"rocksdb.column.family.id": {},
"rocksdb.fixed.key.length": {},
"rocksdb.index.key.is.user.key": {},
"rocksdb.index.value.is.delta.encoded": {},
"rocksdb.oldest.key.time": {},
"rocksdb.creation.time": {},
"rocksdb.file.creation.time": {},
"rocksdb.format.version": {},
}
func (c Compression) String() string {
switch c {
case DefaultCompression:
return "Default"
case NoCompression:
return "NoCompression"
case SnappyCompression:
return "Snappy"
case ZstdCompression:
return "ZSTD"
default:
return "Unknown"
}
}
// FilterType exports the base.FilterType type.
type FilterType = base.FilterType
// Exported TableFilter constants.
const (
TableFilter = base.TableFilter
)
// FilterWriter exports the base.FilterWriter type.
type FilterWriter = base.FilterWriter
// FilterPolicy exports the base.FilterPolicy type.
type FilterPolicy = base.FilterPolicy
// TablePropertyCollector provides a hook for collecting user-defined
// properties based on the keys and values stored in an sstable. A new
// TablePropertyCollector is created for an sstable when the sstable is being
// written.
type TablePropertyCollector interface {
// Add is called with each new entry added to the sstable. While the sstable
// is itself sorted by key, do not assume that the entries are added in any
// order. In particular, the ordering of point entries and range tombstones
// is unspecified.
Add(key InternalKey, value []byte) error
// Finish is called when all entries have been added to the sstable. The
// collected properties (if any) should be added to the specified map. Note
// that in case of an error during sstable construction, Finish may not be
// called.
Finish(userProps map[string]string) error
// The name of the property collector.
Name() string
}
// SuffixReplaceableTableCollector is an extension to the TablePropertyCollector
// interface that allows a table property collector to indicate that it supports
// being *updated* during suffix replacement, i.e. when an existing SST in which
// all keys have the same key suffix is updated to have a new suffix.
//
// A collector which supports being updated in such cases must be able to derive
// its updated value from its old value and the change being made to the suffix,
// without needing to be passed each updated K/V.
//
// For example, a collector that only inspects values can simply copy its
// previously computed property as-is, since key-suffix replacement does not
// change values, while a collector that depends only on key suffixes, like one
// which collected mvcc-timestamp bounds from timestamp-suffixed keys, can just
// set its new bounds from the new suffix, as it is common to all keys, without
// needing to recompute it from every key.
type SuffixReplaceableTableCollector interface {
// UpdateKeySuffixes is called when a table is updated to change the suffix of
// all keys in the table, and is passed the old value for that prop, if any,
// for that table as well as the old and new suffix.
UpdateKeySuffixes(oldProps map[string]string, oldSuffix, newSuffix []byte) error
}
// ReaderOptions holds the parameters needed for reading an sstable.
type ReaderOptions struct {
// Cache is used to cache uncompressed blocks from sstables.
//
// The default cache size is a zero-size cache.
Cache *cache.Cache
// User properties specified in this map will not be added to sst.Properties.UserProperties.
DeniedUserProperties map[string]struct{}
// 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
// Merge defines the Merge function in use for this keyspace.
Merge base.Merge
// Filters is a map from filter policy name to filter policy. It is used for
// debugging tools which may be used on multiple databases configured with
// different filter policies. It is not necessary to populate this filters
// map during normal usage of a DB.
Filters map[string]FilterPolicy
// Merger defines the associative merge operation to use for merging values
// written with {Batch,DB}.Merge. The MergerName is checked for consistency
// with the value stored in the sstable when it was written.
MergerName string
// Logger is an optional logger and tracer.
LoggerAndTracer base.LoggerAndTracer
}
func (o ReaderOptions) ensureDefaults() ReaderOptions {
if o.Comparer == nil {
o.Comparer = base.DefaultComparer
}
if o.Merge == nil {
o.Merge = base.DefaultMerger.Merge
}
if o.MergerName == "" {
o.MergerName = base.DefaultMerger.Name
}
if o.LoggerAndTracer == nil {
o.LoggerAndTracer = base.NoopLoggerAndTracer{}
}
if o.DeniedUserProperties == nil {
o.DeniedUserProperties = ignoredInternalProperties
}
return o
}
// WriterOptions holds the parameters used to control building an sstable.
type WriterOptions struct {
// BlockRestartInterval is the number of keys between restart points
// for delta encoding of keys.
//
// The default value is 16.
BlockRestartInterval int
// BlockSize is the target uncompressed size in bytes of each table block.
//
// The default value is 4096.
BlockSize int
// BlockSizeThreshold finishes a block if the block size is larger than the
// specified percentage of the target block size and adding the next entry
// would cause the block to be larger than the target block size.
//
// The default value is 90
BlockSizeThreshold int
// Cache is used to cache uncompressed blocks from sstables.
//
// The default is a nil cache.
Cache *cache.Cache
// 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
// Compression defines the per-block compression to use.
//
// The default value (DefaultCompression) uses snappy compression.
Compression Compression
// FilterPolicy defines a filter algorithm (such as a Bloom filter) that can
// reduce disk reads for Get calls.
//
// One such implementation is bloom.FilterPolicy(10) from the pebble/bloom
// package.
//
// The default value means to use no filter.
FilterPolicy FilterPolicy
// FilterType defines whether an existing filter policy is applied at a
// block-level or table-level. Block-level filters use less memory to create,
// but are slower to access as a check for the key in the index must first be
// performed to locate the filter block. A table-level filter will require
// memory proportional to the number of keys in an sstable to create, but
// avoids the index lookup when determining if a key is present. Table-level
// filters should be preferred except under constrained memory situations.
FilterType FilterType
// IndexBlockSize is the target uncompressed size in bytes of each index
// block. When the index block size is larger than this target, two-level
// indexes are automatically enabled. Setting this option to a large value
// (such as math.MaxInt32) disables the automatic creation of two-level
// indexes.
//
// The default value is the value of BlockSize.
IndexBlockSize int
// Merger defines the associative merge operation to use for merging values
// written with {Batch,DB}.Merge. The MergerName is checked for consistency
// with the value stored in the sstable when it was written.
MergerName string
// TableFormat specifies the format version for writing sstables. The default
// is TableFormatRocksDBv2 which creates RocksDB compatible sstables. Use
// TableFormatLevelDB to create LevelDB compatible sstable which can be used
// by a wider range of tools and libraries.
TableFormat TableFormat
// IsStrictObsolete is only relevant for >= TableFormatPebblev4. See comment
// in format.go. Must be false if format < TableFormatPebblev4.
//
// TODO(bilal): set this when writing shared ssts.
IsStrictObsolete bool
// WritingToLowestLevel is only relevant for >= TableFormatPebblev4. It is
// used to set the obsolete bit on DEL/DELSIZED/SINGLEDEL if they are the
// youngest for a userkey.
WritingToLowestLevel bool
// TablePropertyCollectors is a list of TablePropertyCollector creation
// functions. A new TablePropertyCollector is created for each sstable built
// and lives for the lifetime of the table.
TablePropertyCollectors []func() TablePropertyCollector
// BlockPropertyCollectors is a list of BlockPropertyCollector creation
// functions. A new BlockPropertyCollector is created for each sstable
// built and lives for the lifetime of writing that table.
BlockPropertyCollectors []func() BlockPropertyCollector
// Checksum specifies which checksum to use.
Checksum ChecksumType
// Parallelism is used to indicate that the sstable Writer is allowed to
// compress data blocks and write datablocks to disk in parallel with the
// Writer client goroutine.
Parallelism bool
// ShortAttributeExtractor mirrors
// Options.Experimental.ShortAttributeExtractor.
ShortAttributeExtractor base.ShortAttributeExtractor
// RequiredInPlaceValueBound mirrors
// Options.Experimental.RequiredInPlaceValueBound.
RequiredInPlaceValueBound UserKeyPrefixBound
}
func (o WriterOptions) ensureDefaults() WriterOptions {
if o.BlockRestartInterval <= 0 {
o.BlockRestartInterval = base.DefaultBlockRestartInterval
}
if o.BlockSize <= 0 {
o.BlockSize = base.DefaultBlockSize
}
if o.BlockSizeThreshold <= 0 {
o.BlockSizeThreshold = base.DefaultBlockSizeThreshold
}
if o.Comparer == nil {
o.Comparer = base.DefaultComparer
}
if o.Compression <= DefaultCompression || o.Compression >= NCompression {
o.Compression = SnappyCompression
}
if o.IndexBlockSize <= 0 {
o.IndexBlockSize = o.BlockSize
}
if o.MergerName == "" {
o.MergerName = base.DefaultMerger.Name
}
if o.Checksum == ChecksumTypeNone {
o.Checksum = ChecksumTypeCRC32c
}
// By default, if the table format is not specified, fall back to using the
// most compatible format.
if o.TableFormat == TableFormatUnspecified {
o.TableFormat = TableFormatRocksDBv2
}
return o
}