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Should flush and sync WAL when writing it in DB::Open() (#6417)

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Summary:
A recent fix related to 2pc https://github.com/facebook/rocksdb/pull/6313/ writes something to WAL, but does not flush or sync. This causes assertion failure "impl->TEST_WALBufferIsEmpty()" if manual_wal_flush = true. We should fsync the entry to make sure a second power reset can recover.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6417

Test Plan: Add manual_wal_flush=true case in TransactionTest.DoubleCrashInRecovery and fix a bug in the test so that the bug can be reproduced. It passes with the fix.

Differential Revision: D19894537

fbshipit-source-id: f1e84e49e2269f583c6019743118292cd8b6598e
This commit is contained in:
sdong 2020-02-13 18:39:38 -08:00 committed by Facebook Github Bot
parent 46516778dd
commit ac8e89a443
2 changed files with 79 additions and 69 deletions
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7
db/db_impl/db_impl_open.cc
View File

@ -1494,6 +1494,13 @@ Status DBImpl::Open(const DBOptions& db_options, const std::string& dbname,
uint64_t log_used, log_size;
log::Writer* log_writer = impl->logs_.back().writer;
s = impl->WriteToWAL(empty_batch, log_writer, &log_used, &log_size);
if (s.ok()) {
// Need to fsync, otherwise it might get lost after a power reset.
s = impl->FlushWAL(false);
if (s.ok()) {
s = log_writer->file()->Sync(impl->immutable_db_options_.use_fsync);
}
}
}
}
}

5
utilities/transactions/transaction_test.cc
View File

@ -6120,8 +6120,10 @@ TEST_P(TransactionTest, ReseekOptimization) {
// there. The new log files should be still read succesfully during recovery of
// the 2nd crash.
TEST_P(TransactionTest, DoubleCrashInRecovery) {
for (const bool manual_wal_flush : {false, true}) {
for (const bool write_after_recovery : {false, true}) {
options.wal_recovery_mode = WALRecoveryMode::kPointInTimeRecovery;
options.manual_wal_flush = manual_wal_flush;
ReOpen();
std::string cf_name = "two";
ColumnFamilyOptions cf_options;
@ -6171,7 +6173,7 @@ TEST_P(TransactionTest, DoubleCrashInRecovery) {
file_content[400] = 'h';
file_content[401] = 'a';
ASSERT_OK(env->DeleteFile(fname));
ASSERT_OK(WriteStringToFile(env, file_content, fname));
ASSERT_OK(WriteStringToFile(env, file_content, fname, true));
// Recover from corruption
std::vector<ColumnFamilyHandle*> handles;
@ -6200,6 +6202,7 @@ TEST_P(TransactionTest, DoubleCrashInRecovery) {
delete handle;
}
}
}
}
} // namespace rocksdb