Re: Hot-standby and canceled queries

On 24 April 2013 12:42, David F. Skoll <dfs(at)roaringpenguin(dot)com> wrote:

> I ran a query on a hot-standby (PostgreSQL 9.1) and it was canceled as
> per the documentation about vacuum cleanups on the master.
>
> Second time testing, I started a transaction on the master (with
> BEGIN) but my query on the hot-standby was still canceled.
>
> Is that because a transaction doesn't "really" begin with BEGIN, but only
> after the first real statement after the BEGIN? Is it sufficient to
> use: BEGIN; SELECT ... ; to start a transaction on the master

Yes

>, or
> do I need to use UPDATE or INSERT to ensure that a vacuum cleanup isn't
> applied until the transaction is finished?

SELECT is sufficient

--
Simon Riggs http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services