Re: SSI patch version 14

On 02/10/2011 05:09 AM, Heikki Linnakangas wrote:
> On 09.02.2011 17:58, Kevin Grittner wrote:
>> Dan Ports<drkp(at)csail(dot)mit(dot)edu> wrote:
>>
>>> I think for SerializableXidHash we should probably just initially
>>> allocate it at its maximum size. Then it'll match the PredXact
>>> list which is allocated in full upfront, and there's no risk of
>>> being able to allocate a transaction but not register its xid. In
>>> fact, I believe there would be no way for starting a new
>>> serializable transaction to fail.
>>
>> To be more precise, it would prevent an out of shared memory error
>> during an attempt to register an xid for an active serializable
>> transaction. That seems like a good thing. Patch to remove the
>> hint and initially allocate that HTAB at full size attached.
>
> Committed.
>
> Curiously, coypu has gone green again. It's now choosing 40
> connections and 8 MB of shared_buffers, while it used to choose 30
> connections and 24 MB of shared_buffers before the SSI patch. Looks
> like fixing the size estimation bugs helped that, but I'm not entirely
> sure how. Maybe it just failed with higher max_connections settings
> because of the misestimate. But why does it now choose a *higher*
> max_connections setting than before?

Rémi might have increased its available resources.

cheers

andrew