On Mon, Jan 18, 2016 at 1:20 PM, Michael Paquier <michael.paqu...@gmail.com> wrote: > On Sun, Jan 17, 2016 at 11:09 PM, Masahiko Sawada <sawada.m...@gmail.com> > wrote: >> On Wed, Jan 13, 2016 at 1:54 AM, Alvaro Herrera wrote: >> * Confirm value of pg_stat_replication.sync_state (sync, async or potential) >> * Confirm that the data is synchronously replicated to multiple >> standbys in same cases. >> * case 1 : The standby which is not listed in s_s_name, is down >> * case 2 : The standby which is listed in s_s_names but potential >> standby, is down >> * case 3 : The standby which is considered as sync standby, is down. >> * Standby promotion >> >> In order to confirm that the commit isn't done in case #3 forever >> unless new sync standby is up, I think we need the framework that >> cancels executing query. >> That is, what I'm planning is, >> 1. Set up master server (s_s_name = '2, standby1, standby2) >> 2. Set up two standby servers >> 3. Standby1 is down >> 4. Create some contents on master (But transaction is not committed) >> 5. Cancel the #4 query. (Also confirm that the flush location of only >> standby2 makes progress) > > This will need some thinking and is not as easy as it sounds. There is > no way to hold on a connection after executing a query in the current > TAP infrastructure. You are just mentioning case 3, but actually cases > 1 and 2 are falling into the same need: if there is a failure we want > to be able to not be stuck in the test forever and have a way to > cancel a query execution at will. TAP uses psql -c to execute any sql > queries, but we would need something that is far lower-level, and that > would be basically using the perl driver for Postgres or an equivalent > here. > > Honestly for those tests I just thought that we could get to something > reliable by just looking at how each sync replication setup reflects > in pg_stat_replication as the flow is really getting complicated, > giving to the user a clear representation at SQL level of what is > actually occurring in the server depending on the configuration used > being important here.
I see. We could check the transition of sync_state in pg_stat_replication. I think it means that it tests for each replication method (switching state) rather than synchronization of replication. What I'm planning to have are, * Confirm value of pg_stat_replication.sync_state (sync, async or potential) * Standby promotion * Standby catching up master And each replication method has above tests. Are these enough? Regards, -- Masahiko Sawada -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
