On 14/02/14 00:49, Tom Lane wrote:
Andres Freund <and...@2ndquadrant.com> writes:
On 2014-02-13 16:15:42 -0500, Tom Lane wrote:
Something like the attached?  Can somebody who's seen this problem confirm
this improves matters?
Hm. Won't that possiby lead to the fast tuple list growing unboundedly?
I think we would need to at least need to stop using the fast tuple
mechanism during gininsert() if it's already too big and do plain
inserts.
No, because we've already got a process working on cleaning it out.

In any case, this needs some testing to see if it's an improvement
or not.

Having some real-world experience with the fastupdate mechanism. Under concurrent load it behaves really bad. Random processes waiting for cleanup (or competing with cleanup) is going to see latency-spikes, because they magically hit that corner, thus reverting to plain inserts if it cannot add to the pending list, will not remove this problem, but will
make it only hit the process actually doing the cleanup.

The build in mechanism, that cleanup is i cost paid by the process who happened to fill the pendinglist, is really hard to deal with in production. More control is appreciated, perhaps even an explicit flush-mechanism.. I'd like to batch up inserts during one transaction only
and flush on commit.

--
Jesper - with fastupdate turned off due to above issues.


--
Jesper


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