Prevent accessing freed XA-committed RocksDB transactions #1513
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With MyRocks DDSE, a XA transaction followed by a DDL statement in the same connection results in the following: - The XA transaction in RocksDB is committed by rocksdb_commit_by_xid, which then deletes the RocksDB transaction object. - The DDL statement in the same thread accesses the deleted object. - If it does not crash first, the next RocksDB commit on that transaction object fails due to the transaction being in unexpected state (COMMITTED instead of STARTED). Fix by: - No longer deleting transactions in rocksdb_commit_by_xid and rocksdb_rollback_by_xid, which was suitable only for crash recovery. - Prevent memory leaks in crash recovery by making the recovered transaction pointer vector in rocksdb_recover public, and deleting all the transactions there in rocksdb_post_recover. - New method Rdb_transaction::restart_if_committed_by_xid with implementation in Rdb_transaction_impl that syncs the MyRocks transaction state with RocksDB by restarting the RocksDB transaction if needed.
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With MyRocks DDSE, a XA transaction followed by a DDL statement in the same
connection results in the following:
then deletes the RocksDB transaction object.
fails due to the transaction being in unexpected state (COMMITTED instead of
STARTED).
Fix by:
rocksdb_rollback_by_xid, which was suitable only for crash recovery.
pointer vector in rocksdb_recover public, and deleting all the transactions
there in rocksdb_post_recover.
Rdb_transaction_impl that syncs the MyRocks transaction state with RocksDB by
restarting the RocksDB transaction if needed.