dimgigov
e1bae0c7a0
- Add docs/ folder with English (en/) and Bulgarian (bg/) documentation - Create index.md with language switching and links - English docs: installation, quickstart, architecture, baraql, storage, schema, lsm, btree, vector, graph, fts, columnar, transactions, distributed, protocol, udf, api-binary, api-http, api-websocket - Bulgarian docs: installation, quickstart, architecture, baraql, schema, lsm, btree, vector, graph, fts, transactions, distributed - Update README license to BSD 3-Clause - Add LICENSE file with BSD 3-Clause text
61 lines
1.1 KiB
Markdown
61 lines
1.1 KiB
Markdown
# Transactions & MVCC
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MVCC (Multi-Version Concurrency Control) with snapshot isolation and deadlock detection.
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## Usage
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```nim
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import barabadb/core/mvcc
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var tm = newTxnManager()
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let txn = tm.beginTxn()
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# Write operations
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discard tm.write(txn, "key1", cast[seq[byte]]("value1"))
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discard tm.write(txn, "key2", cast[seq[byte]]("value2"))
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# Savepoint
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tm.savepoint(txn)
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discard tm.write(txn, "key3", cast[seq[byte]]("value3"))
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discard tm.rollbackToSavepoint(txn) # undo key3
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# Commit
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discard tm.commit(txn)
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```
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## Transaction Isolation
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BaraDB uses **snapshot isolation**:
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- Readers don't block writers
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- Writers don't block readers
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- Each transaction sees a consistent snapshot
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## Deadlock Detection
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```nim
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import barabadb/core/deadlock
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var detector = newDeadlockDetector()
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if detector.detectCycle(txn1, txn2):
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echo "Deadlock detected!"
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```
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## Write-Ahead Log
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```nim
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import barabadb/storage/wal
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var wal = newWAL("./wal")
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wal.append(txnId, "SET key value")
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wal.flush()
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```
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## Savepoints
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Nested transaction savepoints:
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```nim
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tm.savepoint(txn, "sp1")
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# ... operations ...
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tm.rollbackToSavepoint(txn, "sp1")
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``` |