Home > mailing lists

pg_dump -j against standbys - Mailing list pgsql-hackers

From	Magnus Hagander
Subject	pg_dump -j against standbys
Date	May 24, 2016 11:27:12
Msg-id	CABUevEx7vVE7X2Rnrw-C7vJj1af8zsoXunsVJqCA8JWfbrab6A@mail.gmail.com Whole thread Raw
Responses	Re: pg_dump -j against standbys Re: pg_dump -j against standbys
List	pgsql-hackers

pg_dump -j against a standby server returns a pretty bad error message when pointed at a standby node:

pg_dump: [archiver (db)] query failed: ERROR: cannot assign TransactionIds during recovery

pg_dump: [archiver (db)] query was: SELECT pg_export_snapshot()

That looks quite scary to the user, and also throws errors in the server log which monitoring tools or DBAs will react to.

PFA a patch that changes this to:

pg_dump: Synchronized snapshots are not supported on standby servers.

Run with --no-synchronized-snapshots instead if you do not need

synchronized snapshots.

which is a message similar (the hint identical) the one you get if you point it at a version older than 9.2 which doesn't have sync snapshots.

I think the cleanest way to do it is to just track if it's a standby in the AH struct as written.

Comments?

From: Alexander Korotkov
Date: 24 May 2016, 10:30:12
Subject: Re: Is the unfair lwlock behavior intended?

From: Nikolay Shaplov
Date: 24 May 2016, 11:46:32
Subject: [PATCH] add missing "USING bloom" into bloom extension documentation