Re: BDR - triggers on receiving node? - Mailing list pgsql-general

From Craig Ringer
Subject Re: BDR - triggers on receiving node?
Date
Msg-id CAMsr+YGNJqhmX_C9gSPJF7gS=fw8CiVGbsEHujhUA33rhoRKew@mail.gmail.com
Whole thread Raw
In response to Re: BDR - triggers on receiving node?  (Peter Mogensen <apm@one.com>)
List pgsql-general


On 25 March 2015 at 20:14, Peter Mogensen <apm@one.com> wrote:


On 2015-03-25 12:32, Craig Ringer wrote:
On 25 March 2015 at 19:15, Peter Mogensen <apm@one.com> wrote:

Say ... I have a table in a BDR replicated database with an "ON UPDATE"
trigger. - and that trigger wants to locally find out the local
txid_snapshot_xmin() when a change was applied to the local node.

Why would you want to do that? Just out of interest?



Because I have a bunch of SELECT queries to the local node, which includes the txid_current() in their result, and I want to be able to recognize a result which was obtained prior to a change reaching the local node.

So you're trying to do cache invalidation / cache verification of some form?

I'm interested in what you're looking at doing, but would probably need a more complete description to offer much input.

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

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