New mysqld server variables

MySQL/InnoDB Server Variables

The following is a list of parameters which MySQL currently support that were added for Facebook's mysqld:

• filesort_max_file_size : Sets the max size of a file to be used by filesort and raises an error if this is hit.
• gap_lock_exceptions : List of table name regex (e.g. 't1,t2,all_tables.*') for queries that require gaplock do not get logged to the gap_lock_log_file if gap_lock_write_log is enabled.
• gap_lock_log_file : Path to the log file for recording queries that use gaplocks.
• gap_lock_raise_error : Queries that run on InnoDB and require a gaplock return an error instead. Since MyRocks does not support gaplocks, this can help catch client applications that depend on gaplocks.
• gap_lock_write_log : Sets whether to log queries that require gaplocks to the gap_lock_log_file.
• histogram_step_size_binlog_group_commit : Step size of the histogram used in tracking number of threads in binlog group commit.
• innodb_buffer_pool_dump_pct : Dumps the hottest N% percent of each buffer pool. Feature from 5.7.
• per_user_session_var_default_val : Per user session variable default value.
• protocol_mode : Allows reducing the amount of metadata returned in the protocol.
• range_optimizer_max_mem_size : Controls the max memory for range optimizer. Feature from 5.7.
• rbr_idempotent_tables : List of tables to allow row-based replication to treat as idempotent.
• select_into_file_fsync_size : Triggers fsync when running SELECT INTO OUTFILE for this number of data bytes.
• select_into_file_fsync_timeout : Timeout/sleep in milliseconds after each fsync with SELECT INTO OUTFILE.
• session_track_gtids : Controls the amount of global transaction ids to be included in a response packet. Feature from 5.7.
• use_db_uuid : Set to use the database UUID for GTID instead of server_uuid to allow per database shard GTID generation.