khenaidoo | d948f77 | 2021-08-11 17:49:24 -0400 | [diff] [blame] | 1 | // Copyright 2015 The etcd Authors |
| 2 | // |
| 3 | // Licensed under the Apache License, Version 2.0 (the "License"); |
| 4 | // you may not use this file except in compliance with the License. |
| 5 | // You may obtain a copy of the License at |
| 6 | // |
| 7 | // http://www.apache.org/licenses/LICENSE-2.0 |
| 8 | // |
| 9 | // Unless required by applicable law or agreed to in writing, software |
| 10 | // distributed under the License is distributed on an "AS IS" BASIS, |
| 11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 12 | // See the License for the specific language governing permissions and |
| 13 | // limitations under the License. |
| 14 | |
| 15 | package backend |
| 16 | |
| 17 | import ( |
| 18 | "bytes" |
| 19 | "math" |
| 20 | "sync" |
| 21 | "sync/atomic" |
| 22 | "time" |
| 23 | |
| 24 | bolt "github.com/coreos/bbolt" |
| 25 | ) |
| 26 | |
| 27 | type BatchTx interface { |
| 28 | ReadTx |
| 29 | UnsafeCreateBucket(name []byte) |
| 30 | UnsafePut(bucketName []byte, key []byte, value []byte) |
| 31 | UnsafeSeqPut(bucketName []byte, key []byte, value []byte) |
| 32 | UnsafeDelete(bucketName []byte, key []byte) |
| 33 | // Commit commits a previous tx and begins a new writable one. |
| 34 | Commit() |
| 35 | // CommitAndStop commits the previous tx and does not create a new one. |
| 36 | CommitAndStop() |
| 37 | } |
| 38 | |
| 39 | type batchTx struct { |
| 40 | sync.Mutex |
| 41 | tx *bolt.Tx |
| 42 | backend *backend |
| 43 | |
| 44 | pending int |
| 45 | } |
| 46 | |
| 47 | func (t *batchTx) UnsafeCreateBucket(name []byte) { |
| 48 | _, err := t.tx.CreateBucket(name) |
| 49 | if err != nil && err != bolt.ErrBucketExists { |
| 50 | plog.Fatalf("cannot create bucket %s (%v)", name, err) |
| 51 | } |
| 52 | t.pending++ |
| 53 | } |
| 54 | |
| 55 | // UnsafePut must be called holding the lock on the tx. |
| 56 | func (t *batchTx) UnsafePut(bucketName []byte, key []byte, value []byte) { |
| 57 | t.unsafePut(bucketName, key, value, false) |
| 58 | } |
| 59 | |
| 60 | // UnsafeSeqPut must be called holding the lock on the tx. |
| 61 | func (t *batchTx) UnsafeSeqPut(bucketName []byte, key []byte, value []byte) { |
| 62 | t.unsafePut(bucketName, key, value, true) |
| 63 | } |
| 64 | |
| 65 | func (t *batchTx) unsafePut(bucketName []byte, key []byte, value []byte, seq bool) { |
| 66 | bucket := t.tx.Bucket(bucketName) |
| 67 | if bucket == nil { |
| 68 | plog.Fatalf("bucket %s does not exist", bucketName) |
| 69 | } |
| 70 | if seq { |
| 71 | // it is useful to increase fill percent when the workloads are mostly append-only. |
| 72 | // this can delay the page split and reduce space usage. |
| 73 | bucket.FillPercent = 0.9 |
| 74 | } |
| 75 | if err := bucket.Put(key, value); err != nil { |
| 76 | plog.Fatalf("cannot put key into bucket (%v)", err) |
| 77 | } |
| 78 | t.pending++ |
| 79 | } |
| 80 | |
| 81 | // UnsafeRange must be called holding the lock on the tx. |
| 82 | func (t *batchTx) UnsafeRange(bucketName, key, endKey []byte, limit int64) ([][]byte, [][]byte) { |
| 83 | bucket := t.tx.Bucket(bucketName) |
| 84 | if bucket == nil { |
| 85 | plog.Fatalf("bucket %s does not exist", bucketName) |
| 86 | } |
| 87 | return unsafeRange(bucket.Cursor(), key, endKey, limit) |
| 88 | } |
| 89 | |
| 90 | func unsafeRange(c *bolt.Cursor, key, endKey []byte, limit int64) (keys [][]byte, vs [][]byte) { |
| 91 | if limit <= 0 { |
| 92 | limit = math.MaxInt64 |
| 93 | } |
| 94 | var isMatch func(b []byte) bool |
| 95 | if len(endKey) > 0 { |
| 96 | isMatch = func(b []byte) bool { return bytes.Compare(b, endKey) < 0 } |
| 97 | } else { |
| 98 | isMatch = func(b []byte) bool { return bytes.Equal(b, key) } |
| 99 | limit = 1 |
| 100 | } |
| 101 | for ck, cv := c.Seek(key); ck != nil && isMatch(ck); ck, cv = c.Next() { |
| 102 | vs = append(vs, cv) |
| 103 | keys = append(keys, ck) |
| 104 | if limit == int64(len(keys)) { |
| 105 | break |
| 106 | } |
| 107 | } |
| 108 | return keys, vs |
| 109 | } |
| 110 | |
| 111 | // UnsafeDelete must be called holding the lock on the tx. |
| 112 | func (t *batchTx) UnsafeDelete(bucketName []byte, key []byte) { |
| 113 | bucket := t.tx.Bucket(bucketName) |
| 114 | if bucket == nil { |
| 115 | plog.Fatalf("bucket %s does not exist", bucketName) |
| 116 | } |
| 117 | err := bucket.Delete(key) |
| 118 | if err != nil { |
| 119 | plog.Fatalf("cannot delete key from bucket (%v)", err) |
| 120 | } |
| 121 | t.pending++ |
| 122 | } |
| 123 | |
| 124 | // UnsafeForEach must be called holding the lock on the tx. |
| 125 | func (t *batchTx) UnsafeForEach(bucketName []byte, visitor func(k, v []byte) error) error { |
| 126 | return unsafeForEach(t.tx, bucketName, visitor) |
| 127 | } |
| 128 | |
| 129 | func unsafeForEach(tx *bolt.Tx, bucket []byte, visitor func(k, v []byte) error) error { |
| 130 | if b := tx.Bucket(bucket); b != nil { |
| 131 | return b.ForEach(visitor) |
| 132 | } |
| 133 | return nil |
| 134 | } |
| 135 | |
| 136 | // Commit commits a previous tx and begins a new writable one. |
| 137 | func (t *batchTx) Commit() { |
| 138 | t.Lock() |
| 139 | t.commit(false) |
| 140 | t.Unlock() |
| 141 | } |
| 142 | |
| 143 | // CommitAndStop commits the previous tx and does not create a new one. |
| 144 | func (t *batchTx) CommitAndStop() { |
| 145 | t.Lock() |
| 146 | t.commit(true) |
| 147 | t.Unlock() |
| 148 | } |
| 149 | |
| 150 | func (t *batchTx) Unlock() { |
| 151 | if t.pending >= t.backend.batchLimit { |
| 152 | t.commit(false) |
| 153 | } |
| 154 | t.Mutex.Unlock() |
| 155 | } |
| 156 | |
| 157 | func (t *batchTx) commit(stop bool) { |
| 158 | // commit the last tx |
| 159 | if t.tx != nil { |
| 160 | if t.pending == 0 && !stop { |
| 161 | return |
| 162 | } |
| 163 | |
| 164 | start := time.Now() |
| 165 | |
| 166 | // gofail: var beforeCommit struct{} |
| 167 | err := t.tx.Commit() |
| 168 | // gofail: var afterCommit struct{} |
| 169 | |
| 170 | commitDurations.Observe(time.Since(start).Seconds()) |
| 171 | atomic.AddInt64(&t.backend.commits, 1) |
| 172 | |
| 173 | t.pending = 0 |
| 174 | if err != nil { |
| 175 | plog.Fatalf("cannot commit tx (%s)", err) |
| 176 | } |
| 177 | } |
| 178 | if !stop { |
| 179 | t.tx = t.backend.begin(true) |
| 180 | } |
| 181 | } |
| 182 | |
| 183 | type batchTxBuffered struct { |
| 184 | batchTx |
| 185 | buf txWriteBuffer |
| 186 | } |
| 187 | |
| 188 | func newBatchTxBuffered(backend *backend) *batchTxBuffered { |
| 189 | tx := &batchTxBuffered{ |
| 190 | batchTx: batchTx{backend: backend}, |
| 191 | buf: txWriteBuffer{ |
| 192 | txBuffer: txBuffer{make(map[string]*bucketBuffer)}, |
| 193 | seq: true, |
| 194 | }, |
| 195 | } |
| 196 | tx.Commit() |
| 197 | return tx |
| 198 | } |
| 199 | |
| 200 | func (t *batchTxBuffered) Unlock() { |
| 201 | if t.pending != 0 { |
| 202 | t.backend.readTx.mu.Lock() |
| 203 | t.buf.writeback(&t.backend.readTx.buf) |
| 204 | t.backend.readTx.mu.Unlock() |
| 205 | if t.pending >= t.backend.batchLimit { |
| 206 | t.commit(false) |
| 207 | } |
| 208 | } |
| 209 | t.batchTx.Unlock() |
| 210 | } |
| 211 | |
| 212 | func (t *batchTxBuffered) Commit() { |
| 213 | t.Lock() |
| 214 | t.commit(false) |
| 215 | t.Unlock() |
| 216 | } |
| 217 | |
| 218 | func (t *batchTxBuffered) CommitAndStop() { |
| 219 | t.Lock() |
| 220 | t.commit(true) |
| 221 | t.Unlock() |
| 222 | } |
| 223 | |
| 224 | func (t *batchTxBuffered) commit(stop bool) { |
| 225 | // all read txs must be closed to acquire boltdb commit rwlock |
| 226 | t.backend.readTx.mu.Lock() |
| 227 | t.unsafeCommit(stop) |
| 228 | t.backend.readTx.mu.Unlock() |
| 229 | } |
| 230 | |
| 231 | func (t *batchTxBuffered) unsafeCommit(stop bool) { |
| 232 | if t.backend.readTx.tx != nil { |
| 233 | if err := t.backend.readTx.tx.Rollback(); err != nil { |
| 234 | plog.Fatalf("cannot rollback tx (%s)", err) |
| 235 | } |
| 236 | t.backend.readTx.reset() |
| 237 | } |
| 238 | |
| 239 | t.batchTx.commit(stop) |
| 240 | |
| 241 | if !stop { |
| 242 | t.backend.readTx.tx = t.backend.begin(false) |
| 243 | } |
| 244 | } |
| 245 | |
| 246 | func (t *batchTxBuffered) UnsafePut(bucketName []byte, key []byte, value []byte) { |
| 247 | t.batchTx.UnsafePut(bucketName, key, value) |
| 248 | t.buf.put(bucketName, key, value) |
| 249 | } |
| 250 | |
| 251 | func (t *batchTxBuffered) UnsafeSeqPut(bucketName []byte, key []byte, value []byte) { |
| 252 | t.batchTx.UnsafeSeqPut(bucketName, key, value) |
| 253 | t.buf.putSeq(bucketName, key, value) |
| 254 | } |