SnapshotResetXmin

Simon Riggs wrote:

SnapshotResetXmin is called 3 times after each statement in
ReadCommitted mode.

Too keen, perhaps?

It is called each time a snapshot is unregistered and each time an
active snapshot is popped. I don't see any way to reduce the number of
calls without complicating the code a lot ... do you have any ideas?

Maybe we could check whether TransState is not TRANS_INPROGRESS and skip
it in those cases ...?

--
Alvaro Herrera http://www.CommandPrompt.com/
PostgreSQL Replication, Consulting, Custom Development, 24x7 support

Alvaro Herrera <alvherre@commandprompt.com> writes:

Simon Riggs wrote:

SnapshotResetXmin is called 3 times after each statement in
ReadCommitted mode.

Maybe we could check whether TransState is not TRANS_INPROGRESS and skip
it in those cases ...?

Surely this would take longer than the function itself does. What's
the point of worrying at all?

regards, tom lane

On Fri, 2009-01-16 at 12:13 -0500, Tom Lane wrote:

Alvaro Herrera <alvherre@commandprompt.com> writes:

Simon Riggs wrote:

SnapshotResetXmin is called 3 times after each statement in
ReadCommitted mode.

Maybe we could check whether TransState is not TRANS_INPROGRESS and skip
it in those cases ...?

Surely this would take longer than the function itself does. What's
the point of worrying at all?

I thought it *might* be indicative of over zealous coding, thats all.

Better a false-positive than to miss a possible issue.

--
Simon Riggs www.2ndQuadrant.com
PostgreSQL Training, Services and Support