On Sun, Nov 13, 2011 at 5:13 PM, Simon Riggs <si...@2ndquadrant.com> wrote: > On Tue, Nov 1, 2011 at 12:11 PM, Simon Riggs <si...@2ndquadrant.com> wrote: > >> When I say skip the shutdown checkpoint, I mean remove it from the >> critical path of required actions at the end of recovery. We can still >> have a normal checkpoint kicked off at that time, but that no longer >> needs to be on the critical path. >> >> Any problems foreseen? If not, looks like a quick patch. > > Patch attached for discussion/review.
This feature is what I want, and very helpful to shorten the failover time in streaming replication. Here are the review comments. Though I've not checked enough whether this feature works fine in all recovery patterns yet. LocalSetXLogInsertAllowed() must be called before LogEndOfRecovery(). LocalXLogInsertAllowed must be set to -1 after LogEndOfRecovery(). XLOG_END_OF_RECOVERY record is written to the WAL file with new assigned timeline ID. But it must be written to the WAL file with old one. Otherwise, when re-entering a recovery after failover, we cannot find XLOG_END_OF_RECOVERY record at all. Before XLOG_END_OF_RECOVERY record is written, RmgrTable[rmid].rm_cleanup() might write WAL records. They also should be written to the WAL file with old timeline ID. When recovery target is specified, we cannot write new WAL to the file with old timeline because which means that valid WAL records in it are overwritten with new WAL. So when recovery target is specified, ISTM that we cannot skip end of recovery checkpoint. Or we might need to save all information about timelines in the database cluster instead of writing XLOG_END_OF_RECOVERY record, and use it when re-entering a recovery. LogEndOfRecovery() seems to need to call XLogFlush(). Otherwise, what if the server crashes after new timeline history file is created and recovery.conf is removed, but before XLOG_END_OF_RECOVERY record has not been flushed to the disk yet? During recovery, when we replay XLOG_END_OF_RECOVERY record, we should close the currently-opened WAL file and read the WAL file with the timeline which XLOG_END_OF_RECOVERY record indicates. Otherwise, when re-entering a recovery with old timeline, we cannot reach new timeline. Regards, -- Fujii Masao NIPPON TELEGRAPH AND TELEPHONE CORPORATION NTT Open Source Software Center -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
