mirror of
https://github.com/astaxie/beego.git
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530 lines
12 KiB
Go
530 lines
12 KiB
Go
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// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
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// All rights reserved.
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//
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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package leveldb
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import (
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"fmt"
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"sort"
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"sync/atomic"
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"github.com/syndtr/goleveldb/leveldb/cache"
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"github.com/syndtr/goleveldb/leveldb/iterator"
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"github.com/syndtr/goleveldb/leveldb/opt"
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"github.com/syndtr/goleveldb/leveldb/storage"
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"github.com/syndtr/goleveldb/leveldb/table"
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"github.com/syndtr/goleveldb/leveldb/util"
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)
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// tFile holds basic information about a table.
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type tFile struct {
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fd storage.FileDesc
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seekLeft int32
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size int64
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imin, imax internalKey
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}
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// Returns true if given key is after largest key of this table.
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func (t *tFile) after(icmp *iComparer, ukey []byte) bool {
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return ukey != nil && icmp.uCompare(ukey, t.imax.ukey()) > 0
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}
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// Returns true if given key is before smallest key of this table.
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func (t *tFile) before(icmp *iComparer, ukey []byte) bool {
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return ukey != nil && icmp.uCompare(ukey, t.imin.ukey()) < 0
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}
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// Returns true if given key range overlaps with this table key range.
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func (t *tFile) overlaps(icmp *iComparer, umin, umax []byte) bool {
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return !t.after(icmp, umin) && !t.before(icmp, umax)
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}
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// Cosumes one seek and return current seeks left.
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func (t *tFile) consumeSeek() int32 {
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return atomic.AddInt32(&t.seekLeft, -1)
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}
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// Creates new tFile.
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func newTableFile(fd storage.FileDesc, size int64, imin, imax internalKey) *tFile {
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f := &tFile{
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fd: fd,
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size: size,
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imin: imin,
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imax: imax,
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}
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// We arrange to automatically compact this file after
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// a certain number of seeks. Let's assume:
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// (1) One seek costs 10ms
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// (2) Writing or reading 1MB costs 10ms (100MB/s)
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// (3) A compaction of 1MB does 25MB of IO:
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// 1MB read from this level
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// 10-12MB read from next level (boundaries may be misaligned)
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// 10-12MB written to next level
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// This implies that 25 seeks cost the same as the compaction
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// of 1MB of data. I.e., one seek costs approximately the
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// same as the compaction of 40KB of data. We are a little
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// conservative and allow approximately one seek for every 16KB
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// of data before triggering a compaction.
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f.seekLeft = int32(size / 16384)
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if f.seekLeft < 100 {
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f.seekLeft = 100
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}
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return f
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}
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func tableFileFromRecord(r atRecord) *tFile {
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return newTableFile(storage.FileDesc{storage.TypeTable, r.num}, r.size, r.imin, r.imax)
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}
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// tFiles hold multiple tFile.
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type tFiles []*tFile
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func (tf tFiles) Len() int { return len(tf) }
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func (tf tFiles) Swap(i, j int) { tf[i], tf[j] = tf[j], tf[i] }
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func (tf tFiles) nums() string {
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x := "[ "
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for i, f := range tf {
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if i != 0 {
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x += ", "
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}
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x += fmt.Sprint(f.fd.Num)
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}
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x += " ]"
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return x
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}
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// Returns true if i smallest key is less than j.
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// This used for sort by key in ascending order.
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func (tf tFiles) lessByKey(icmp *iComparer, i, j int) bool {
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a, b := tf[i], tf[j]
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n := icmp.Compare(a.imin, b.imin)
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if n == 0 {
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return a.fd.Num < b.fd.Num
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}
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return n < 0
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}
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// Returns true if i file number is greater than j.
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// This used for sort by file number in descending order.
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func (tf tFiles) lessByNum(i, j int) bool {
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return tf[i].fd.Num > tf[j].fd.Num
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}
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// Sorts tables by key in ascending order.
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func (tf tFiles) sortByKey(icmp *iComparer) {
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sort.Sort(&tFilesSortByKey{tFiles: tf, icmp: icmp})
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}
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// Sorts tables by file number in descending order.
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func (tf tFiles) sortByNum() {
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sort.Sort(&tFilesSortByNum{tFiles: tf})
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}
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// Returns sum of all tables size.
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func (tf tFiles) size() (sum int64) {
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for _, t := range tf {
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sum += t.size
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}
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return sum
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}
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// Searches smallest index of tables whose its smallest
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// key is after or equal with given key.
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func (tf tFiles) searchMin(icmp *iComparer, ikey internalKey) int {
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return sort.Search(len(tf), func(i int) bool {
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return icmp.Compare(tf[i].imin, ikey) >= 0
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})
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}
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// Searches smallest index of tables whose its largest
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// key is after or equal with given key.
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func (tf tFiles) searchMax(icmp *iComparer, ikey internalKey) int {
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return sort.Search(len(tf), func(i int) bool {
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return icmp.Compare(tf[i].imax, ikey) >= 0
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})
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}
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// Returns true if given key range overlaps with one or more
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// tables key range. If unsorted is true then binary search will not be used.
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func (tf tFiles) overlaps(icmp *iComparer, umin, umax []byte, unsorted bool) bool {
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if unsorted {
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// Check against all files.
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for _, t := range tf {
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if t.overlaps(icmp, umin, umax) {
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return true
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}
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}
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return false
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}
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i := 0
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if len(umin) > 0 {
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// Find the earliest possible internal key for min.
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i = tf.searchMax(icmp, makeInternalKey(nil, umin, keyMaxSeq, keyTypeSeek))
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}
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if i >= len(tf) {
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// Beginning of range is after all files, so no overlap.
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return false
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}
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return !tf[i].before(icmp, umax)
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}
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// Returns tables whose its key range overlaps with given key range.
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// Range will be expanded if ukey found hop across tables.
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// If overlapped is true then the search will be restarted if umax
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// expanded.
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// The dst content will be overwritten.
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func (tf tFiles) getOverlaps(dst tFiles, icmp *iComparer, umin, umax []byte, overlapped bool) tFiles {
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dst = dst[:0]
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for i := 0; i < len(tf); {
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t := tf[i]
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if t.overlaps(icmp, umin, umax) {
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if umin != nil && icmp.uCompare(t.imin.ukey(), umin) < 0 {
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umin = t.imin.ukey()
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dst = dst[:0]
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i = 0
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continue
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} else if umax != nil && icmp.uCompare(t.imax.ukey(), umax) > 0 {
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umax = t.imax.ukey()
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// Restart search if it is overlapped.
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if overlapped {
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dst = dst[:0]
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i = 0
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continue
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}
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}
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dst = append(dst, t)
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}
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i++
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}
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return dst
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}
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// Returns tables key range.
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func (tf tFiles) getRange(icmp *iComparer) (imin, imax internalKey) {
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for i, t := range tf {
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if i == 0 {
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imin, imax = t.imin, t.imax
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continue
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}
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if icmp.Compare(t.imin, imin) < 0 {
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imin = t.imin
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}
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if icmp.Compare(t.imax, imax) > 0 {
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imax = t.imax
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}
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}
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return
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}
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// Creates iterator index from tables.
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func (tf tFiles) newIndexIterator(tops *tOps, icmp *iComparer, slice *util.Range, ro *opt.ReadOptions) iterator.IteratorIndexer {
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if slice != nil {
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var start, limit int
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if slice.Start != nil {
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start = tf.searchMax(icmp, internalKey(slice.Start))
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}
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if slice.Limit != nil {
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limit = tf.searchMin(icmp, internalKey(slice.Limit))
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} else {
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limit = tf.Len()
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}
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tf = tf[start:limit]
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}
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return iterator.NewArrayIndexer(&tFilesArrayIndexer{
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tFiles: tf,
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tops: tops,
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icmp: icmp,
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slice: slice,
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ro: ro,
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})
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}
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// Tables iterator index.
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type tFilesArrayIndexer struct {
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tFiles
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tops *tOps
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icmp *iComparer
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slice *util.Range
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ro *opt.ReadOptions
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}
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func (a *tFilesArrayIndexer) Search(key []byte) int {
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return a.searchMax(a.icmp, internalKey(key))
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}
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func (a *tFilesArrayIndexer) Get(i int) iterator.Iterator {
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if i == 0 || i == a.Len()-1 {
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return a.tops.newIterator(a.tFiles[i], a.slice, a.ro)
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}
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return a.tops.newIterator(a.tFiles[i], nil, a.ro)
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}
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// Helper type for sortByKey.
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type tFilesSortByKey struct {
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tFiles
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icmp *iComparer
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}
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func (x *tFilesSortByKey) Less(i, j int) bool {
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return x.lessByKey(x.icmp, i, j)
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}
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// Helper type for sortByNum.
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type tFilesSortByNum struct {
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tFiles
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}
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func (x *tFilesSortByNum) Less(i, j int) bool {
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return x.lessByNum(i, j)
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}
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// Table operations.
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type tOps struct {
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s *session
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noSync bool
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cache *cache.Cache
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bcache *cache.Cache
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bpool *util.BufferPool
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}
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// Creates an empty table and returns table writer.
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func (t *tOps) create() (*tWriter, error) {
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fd := storage.FileDesc{storage.TypeTable, t.s.allocFileNum()}
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fw, err := t.s.stor.Create(fd)
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if err != nil {
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return nil, err
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}
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return &tWriter{
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t: t,
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fd: fd,
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w: fw,
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tw: table.NewWriter(fw, t.s.o.Options),
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}, nil
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}
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// Builds table from src iterator.
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func (t *tOps) createFrom(src iterator.Iterator) (f *tFile, n int, err error) {
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w, err := t.create()
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if err != nil {
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return
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}
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defer func() {
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if err != nil {
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w.drop()
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}
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}()
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for src.Next() {
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err = w.append(src.Key(), src.Value())
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if err != nil {
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return
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}
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}
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err = src.Error()
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if err != nil {
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return
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}
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n = w.tw.EntriesLen()
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f, err = w.finish()
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return
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}
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// Opens table. It returns a cache handle, which should
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// be released after use.
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func (t *tOps) open(f *tFile) (ch *cache.Handle, err error) {
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ch = t.cache.Get(0, uint64(f.fd.Num), func() (size int, value cache.Value) {
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var r storage.Reader
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r, err = t.s.stor.Open(f.fd)
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if err != nil {
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return 0, nil
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}
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var bcache *cache.NamespaceGetter
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if t.bcache != nil {
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bcache = &cache.NamespaceGetter{Cache: t.bcache, NS: uint64(f.fd.Num)}
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}
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var tr *table.Reader
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tr, err = table.NewReader(r, f.size, f.fd, bcache, t.bpool, t.s.o.Options)
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if err != nil {
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r.Close()
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return 0, nil
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}
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return 1, tr
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})
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if ch == nil && err == nil {
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err = ErrClosed
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}
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return
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}
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// Finds key/value pair whose key is greater than or equal to the
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// given key.
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func (t *tOps) find(f *tFile, key []byte, ro *opt.ReadOptions) (rkey, rvalue []byte, err error) {
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ch, err := t.open(f)
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if err != nil {
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return nil, nil, err
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}
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defer ch.Release()
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return ch.Value().(*table.Reader).Find(key, true, ro)
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}
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// Finds key that is greater than or equal to the given key.
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func (t *tOps) findKey(f *tFile, key []byte, ro *opt.ReadOptions) (rkey []byte, err error) {
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ch, err := t.open(f)
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if err != nil {
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return nil, err
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}
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defer ch.Release()
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return ch.Value().(*table.Reader).FindKey(key, true, ro)
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}
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// Returns approximate offset of the given key.
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func (t *tOps) offsetOf(f *tFile, key []byte) (offset int64, err error) {
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ch, err := t.open(f)
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if err != nil {
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return
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}
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defer ch.Release()
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return ch.Value().(*table.Reader).OffsetOf(key)
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}
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// Creates an iterator from the given table.
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func (t *tOps) newIterator(f *tFile, slice *util.Range, ro *opt.ReadOptions) iterator.Iterator {
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ch, err := t.open(f)
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if err != nil {
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return iterator.NewEmptyIterator(err)
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}
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iter := ch.Value().(*table.Reader).NewIterator(slice, ro)
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iter.SetReleaser(ch)
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return iter
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}
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// Removes table from persistent storage. It waits until
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// no one use the the table.
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func (t *tOps) remove(f *tFile) {
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t.cache.Delete(0, uint64(f.fd.Num), func() {
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if err := t.s.stor.Remove(f.fd); err != nil {
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t.s.logf("table@remove removing @%d %q", f.fd.Num, err)
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} else {
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t.s.logf("table@remove removed @%d", f.fd.Num)
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}
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if t.bcache != nil {
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t.bcache.EvictNS(uint64(f.fd.Num))
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}
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})
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}
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// Closes the table ops instance. It will close all tables,
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// regadless still used or not.
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func (t *tOps) close() {
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t.bpool.Close()
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t.cache.Close()
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if t.bcache != nil {
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t.bcache.Close()
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}
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}
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||
|
// Creates new initialized table ops instance.
|
||
|
func newTableOps(s *session) *tOps {
|
||
|
var (
|
||
|
cacher cache.Cacher
|
||
|
bcache *cache.Cache
|
||
|
bpool *util.BufferPool
|
||
|
)
|
||
|
if s.o.GetOpenFilesCacheCapacity() > 0 {
|
||
|
cacher = cache.NewLRU(s.o.GetOpenFilesCacheCapacity())
|
||
|
}
|
||
|
if !s.o.GetDisableBlockCache() {
|
||
|
var bcacher cache.Cacher
|
||
|
if s.o.GetBlockCacheCapacity() > 0 {
|
||
|
bcacher = cache.NewLRU(s.o.GetBlockCacheCapacity())
|
||
|
}
|
||
|
bcache = cache.NewCache(bcacher)
|
||
|
}
|
||
|
if !s.o.GetDisableBufferPool() {
|
||
|
bpool = util.NewBufferPool(s.o.GetBlockSize() + 5)
|
||
|
}
|
||
|
return &tOps{
|
||
|
s: s,
|
||
|
noSync: s.o.GetNoSync(),
|
||
|
cache: cache.NewCache(cacher),
|
||
|
bcache: bcache,
|
||
|
bpool: bpool,
|
||
|
}
|
||
|
}
|
||
|
|
||
|
// tWriter wraps the table writer. It keep track of file descriptor
|
||
|
// and added key range.
|
||
|
type tWriter struct {
|
||
|
t *tOps
|
||
|
|
||
|
fd storage.FileDesc
|
||
|
w storage.Writer
|
||
|
tw *table.Writer
|
||
|
|
||
|
first, last []byte
|
||
|
}
|
||
|
|
||
|
// Append key/value pair to the table.
|
||
|
func (w *tWriter) append(key, value []byte) error {
|
||
|
if w.first == nil {
|
||
|
w.first = append([]byte{}, key...)
|
||
|
}
|
||
|
w.last = append(w.last[:0], key...)
|
||
|
return w.tw.Append(key, value)
|
||
|
}
|
||
|
|
||
|
// Returns true if the table is empty.
|
||
|
func (w *tWriter) empty() bool {
|
||
|
return w.first == nil
|
||
|
}
|
||
|
|
||
|
// Closes the storage.Writer.
|
||
|
func (w *tWriter) close() {
|
||
|
if w.w != nil {
|
||
|
w.w.Close()
|
||
|
w.w = nil
|
||
|
}
|
||
|
}
|
||
|
|
||
|
// Finalizes the table and returns table file.
|
||
|
func (w *tWriter) finish() (f *tFile, err error) {
|
||
|
defer w.close()
|
||
|
err = w.tw.Close()
|
||
|
if err != nil {
|
||
|
return
|
||
|
}
|
||
|
if !w.t.noSync {
|
||
|
err = w.w.Sync()
|
||
|
if err != nil {
|
||
|
return
|
||
|
}
|
||
|
}
|
||
|
f = newTableFile(w.fd, int64(w.tw.BytesLen()), internalKey(w.first), internalKey(w.last))
|
||
|
return
|
||
|
}
|
||
|
|
||
|
// Drops the table.
|
||
|
func (w *tWriter) drop() {
|
||
|
w.close()
|
||
|
w.t.s.stor.Remove(w.fd)
|
||
|
w.t.s.reuseFileNum(w.fd.Num)
|
||
|
w.tw = nil
|
||
|
w.first = nil
|
||
|
w.last = nil
|
||
|
}
|