Hi, Sujatha! Could you split this patch, please?
1. Just add replication_applier_status_by_worker table. With CHANNEL_NAME column and (perhaps, not sure if it applies) with WORKER_ID column. Without extra columns and backup. 2. Add extra columns. 3. Add backup. With these three commits you'll have exactly the same diff as now, just split (and with CHANNEL_NAME column). But really, I wonder whether this backup functionality is needed at all? In MySQL there is persistent information about these workers, it doesn't go away when they're stopped, it's stored persistently in a table, indexed by worker_id. If we don't have anything persistent like that and all workers completely disappear into oblivion, then, may be, replication_applier_status_by_worker should not show anything when they aren't running? If you agree, then you'll only need two commits. Regards, Sergei VP of MariaDB Server Engineering and [email protected] On Mar 21, Sujatha wrote: > revision-id: e5fc78f84e3 (mariadb-10.5.2-303-ge5fc78f84e3) > parent(s): 8b8969929d7 > author: Sujatha <[email protected]> > committer: Sujatha <[email protected]> > timestamp: 2020-11-27 12:59:42 +0530 > message: > > MDEV-20220: Merge 5.7 P_S replication table > 'replication_applier_status_by_worker > > Fix: > === > Iterate through rpl_parallel_thread_pool and display slave worker thread > specific information as part of 'replication_applier_status_by_worker' table. > > --------------------------------------------------------------------------------- > |Column Name: | Description: > | > |-------------------------------------------------------------------------------| > | | > | > |THREAD_ID | Thread_Id as displayed in > 'performance_schema.threads'| > | | table for thread with name > | > | | 'thread/sql/rpl_parallel_thread' > | > | | > | > | | THREAD_ID will be NULL when worker threads are > stopped| > | | due to error/force stop > | > | | > | > |SERVICE_STATE | Thread is running or not > | > | | > | > |LAST_SEEN_TRANSACTION | Last GTID executed by worker > | > | | > | > |LAST_ERROR_NUMBER | Last Error that occurred on a particular worker > | > | | > | > |LAST_ERROR_MESSAGE | Last error specific message > | > | | > | > |LAST_ERROR_TIMESTAMP | Time stamp of last error > | > | | > | > |WORKER_IDLE_TIME | Total idle time in seconds that the worker thread > has | > | | spent waiting for work from SQL thread > | > | | > | > |LAST_TRANS_RETRY_COUNT | Total number of retries attempted by last > transaction | > --------------------------------------------------------------------------------- > > > In case STOP SLAVE is executed worker threads will be gone, hence worker > threads will be unavailable. Querying the table at this stage will give empty > rows. To address this case when worker threads are about to stop, due to an > error or forced stop, create a backup pool and preserve the data which is > relevant to populate performance schema table. Clear the backup pool upon > slave start. _______________________________________________ Mailing list: https://launchpad.net/~maria-developers Post to : [email protected] Unsubscribe : https://launchpad.net/~maria-developers More help : https://help.launchpad.net/ListHelp
