Hi Andres, Thank you for your prompt response.
I've confirmed in REL9_1_STABLE and could not reproduce that issue. Also confirm the source and did not find problem with it. Regard, --- Dang Minh Huong NEC Soft,Ltd. http://www.necsoft.com/eng/ > -----Original Message----- > From: Andres Freund [mailto:and...@2ndquadrant.com] > Sent: Thursday, August 22, 2013 10:31 PM > To: ダンミンフーン > Cc: pgsql-bugs@postgresql.org; 'Akio Iwaasa' > Subject: Re: [BUGS] After promote, DB can not UPDATE with SAVEPOINT (could > not access status of transaction > 1409172) > > Hi, > > On 2013-08-22 22:17:40 +0900, ダンミンフーン wrote: > > I've get found out that issue in my project. > > Update in PRIMARY while pg_basebackup is performing, Can cause the > > STANDBY could not UPDATE after promote. > > > > In Standby Node, when first XID of a page come, pg_subtrans must be > > extended by ExtendSUBTRANS function. > > > > But if that XID created while pg_basebackup (with "-x" option) was > > performing, it did not extend. > > > > Due to that, after basebackup complete, start that DB and do promote > > complete. It failed in SAVEPOINT UPDATE query like follows. > > > > --- > > postgres=# BEGIN; > > postgres=# SAVEPOINT testsavepoint; > > postgres=# UPDATE test_tbl SET name = 'test'; > > ERROR: could not access status of transaction 1409172 > > DETAIL: Could not read from file "pg_subtrans/0015" at offset 131072: > > Success. > > --- > > > > I've also confirm source and realize that, > > > > When StartupXLOG call RecordKnownAssignedTransactionIds (in the "main > > redo apply loop"), the "standbyState" still was STANDBY_INITIALIZED, > > so it is returned without goto ExtendSUBTRANS (to check and extend > > space for pg_subtrans). > > > > Therefor, after STANDBY promote, when UPDATE query made by SAVEPOINT > > is executed, the process as follow is performed and get the above > > ERROR in SimpleLruReadPage function. > > > > AssignTransactionId => SubTransSetParent => SubTransSetParent => > > SimpleLruReadPage > > > > I think that ExtendSUBTRANS must be called even if "standbyState" > > in STANDBY_INITIALIZED in order to avoid the case above. > > > > I also attach a patch. Could anyone confirm for me. > > Nice diagnosis and thanks for the patch! > > I think the the issue has already been fixed while investigating a similar > issue, could you verify that the > current git version works for you? > > c.f. commit 99ee15b315c187045a95db7b27fd9d866aea93e0 > > Greetings, > > Andres Freund > > -- > Andres Freund http://www.2ndQuadrant.com/ > PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-bugs mailing list (pgsql-bugs@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-bugs
