WL#10477: Defaults: Enable Transaction Write Sets
Affects: Server-8.0 — Status: Complete
Rationale ========= By using Transaction Write Sets, the master has to do slightly more work to generate the write sets which is helpfull in conflict detection. This allows users to easily move into GR since transaction-write-set is a requirement for GR. Also, the new default will make users to easily enable binary log writeset parallelization on master to speed up replication. https://dev.mysql.com/doc/refman/8.0/en/replication-options-binary- log.html#sysvar_binlog_transaction_dependency_tracking Server Changes ============== transaction-write-set-extraction = XXHASH64 : Enables the optimal method for generating the write set hashes. Upgrade Story ============= There are no special upgrade considerations with regards to a single instance. But we need to ensure that 5.x and 8.0 replication topologies can coexist as per usual, in particular the fu11y supported n+1 --> n replication. Acceptance Criteria =================== 1. The setting should not cause any instability/failures in our automated tests. 2. The setting should not cause performance regressions of more than 5% on the master on average in SysQA perf tests.
Functional Requirements: ======================== FR1: It shall be possible to run all existing statements and workloads with new default "transaction-write-set-extraction = XXHASH64",which will be verified by changing the defaults on all existing replication tests suites. Non-functional requirements: ============================ NF1: The new default settings shall not cause any performance regressions of more than 5% on average on master.
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