Обсуждение: Re: [ADMIN] is replication effected by exclusive locks?

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Re: [ADMIN] is replication effected by exclusive locks?

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Steven Chang
Дата:
yes if using stream replication due to lock command also being transferred to slave node

steven

2017-03-26 3:02 GMT+08:00 gleeco <gleeco@gmail.com>:

hello - first a thank-you to this list for all previous questions answered here!

In our cluster, we're using read-only replicas for answering postgis geo queries.  Often, i see multiple queries coming in concurrently & regularly taking 2-10 seconds.   When looking closer at these queries, i see they all use an ExclusiveLock.   

And when this is the query traffic, there can be increasing replication lag.
But also - there can be waves of tx cancellation due to conflicts, ie. replication.

note that in this setup, pg_vacuum_defer_cleanup_age = 0 so the cancels make sense to me.

So the simple question: do ExclusiveLock compete or block application of wal logs on read replicas?

thanks in advance for thoughts/tips/links/etc