Re: More subtle issues with cascading replication over timeline switches
От | Amit kapila |
---|---|
Тема | Re: More subtle issues with cascading replication over timeline switches |
Дата | |
Msg-id | 6C0B27F7206C9E4CA54AE035729E9C383BEB8D38@szxeml509-mbx обсуждение исходный текст |
Ответ на | More subtle issues with cascading replication over timeline switches (Heikki Linnakangas <hlinnakangas@vmware.com>) |
Ответы |
Re: More subtle issues with cascading replication over
timeline switches
|
Список | pgsql-hackers |
On Friday, January 18, 2013 5:27 PM Heikki Linnakangas wrote: > Indeed, looking at the pg_xlog, it's not there (I did a couple of extra > timeline switches: > ~/pgsql.master$ ls -l data-master/pg_xlog/ > total 131084 > -rw------- 1 heikki heikki 16777216 Jan 18 13:38 000000010000000000000001 > -rw------- 1 heikki heikki 16777216 Jan 18 13:38 000000010000000000000002 > -rw------- 1 heikki heikki 16777216 Jan 18 13:38 000000010000000000000003 > -rw------- 1 heikki heikki 41 Jan 18 13:38 00000002.history > -rw------- 1 heikki heikki 16777216 Jan 18 13:38 000000020000000000000003 > -rw------- 1 heikki heikki 16777216 Jan 18 13:38 000000020000000000000004 > -rw------- 1 heikki heikki 16777216 Jan 18 13:38 000000020000000000000005 > -rw------- 1 heikki heikki 83 Jan 18 13:38 00000003.history > -rw------- 1 heikki heikki 16777216 Jan 18 13:38 000000030000000000000005 > -rw------- 1 heikki heikki 16777216 Jan 18 13:38 000000030000000000000006 > drwx------ 2 heikki heikki 4096 Jan 18 13:38 archive_status > ~/pgsql.master$ ls -l data-standbyB/pg_xlog/ > total 81928 > -rw------- 1 heikki heikki 16777216 Jan 18 13:38 000000010000000000000001 > -rw------- 1 heikki heikki 16777216 Jan 18 13:38 000000010000000000000002 > -rw------- 1 heikki heikki 16777216 Jan 18 13:38 000000020000000000000003 > -rw------- 1 heikki heikki 16777216 Jan 18 13:38 000000020000000000000004 > -rw------- 1 heikki heikki 83 Jan 18 13:38 00000003.history > -rw------- 1 heikki heikki 16777216 Jan 18 13:38 000000030000000000000005 > drwx------ 2 heikki heikki 4096 Jan 18 13:38 archive_status > This can be thought of as another variant of the same issue that was > fixed by commit 60df192aea0e6458f20301546e11f7673c102101. When standby B > scans for the latest timeline, it finds it to be 3, and it reads the > timeline history file for 3. After that patch, it also saves it in > pg_xlog. It doesn't save the timeline history file for timeline 2, > because that's included in the history of timeline 3. However, when > standby C connects, it will try to fetch all the history files that it > doesn't have, including 00000002.history, which throws the error. Is the file 00000002.history really required by standby C for any useful purpose? Can we think of change in current designsuch that when standby C connects, even if some old history file (like 00000002.history) is not present, it ignoresthe same and continue. With Regards, Amit Kapila.
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