Cai Liuyang created FLINK-29577:
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Summary: Disable rocksdb wal when restore from full snapshot
Key: FLINK-29577
URL: https://issues.apache.org/jira/browse/FLINK-29577
Project: Flink
Issue Type: Improvement
Components: Runtime / State Backends
Reporter: Cai Liuyang
For now, RocksDBFullRestoreOperation and RocksDBHeapTimersFullRestoreOperation
does's pass RocksDB::WriteOptions to RocksDBWriteBatchWrapper when restore
kv-data, which will use RocksDBWriteBatchWrapper‘s default WriteOptions(doesn't
disable rocksdb wal explicitly, see code below), so during restoring from full
snapshot, wal is enabled(use more disk and affect rocksdb-write-performance
when restoring)
{code:java}
// First: RocksDBHeapTimersFullRestoreOperation::restoreKVStateData() doesn't
pass WriteOptions to RocksDBWriteBatchWrapper(null as default)
private void restoreKVStateData(
ThrowingIterator<KeyGroup> keyGroups,
Map<Integer, ColumnFamilyHandle> columnFamilies,
Map<Integer, HeapPriorityQueueSnapshotRestoreWrapper<?>>
restoredPQStates)
throws IOException, RocksDBException, StateMigrationException {
// for all key-groups in the current state handle...
try (RocksDBWriteBatchWrapper writeBatchWrapper =
new RocksDBWriteBatchWrapper(this.rocksHandle.getDb(),
writeBatchSize)) {
HeapPriorityQueueSnapshotRestoreWrapper<HeapPriorityQueueElement>
restoredPQ = null;
ColumnFamilyHandle handle = null;
......
}
// Second: RocksDBWriteBatchWrapper::flush function doesn't disable wal
explicitly when user doesn't pass WriteOptions to RocksDBWriteBatchWrapper
public void flush() throws RocksDBException {
if (options != null) {
db.write(options, batch);
} else {
// use the default WriteOptions, if wasn't provided.
try (WriteOptions writeOptions = new WriteOptions()) {
db.write(writeOptions, batch);
}
}
batch.clear();
}
{code}
As we known, rocksdb's wal is usesless for flink, so i think we can disable wal
for RocksDBWriteBatchWrapper's default WriteOptions.
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