Re: Index-only scan performance regression - Mailing list pgsql-hackers

From Dean Rasheed
Subject Re: Index-only scan performance regression
Date
Msg-id CAEZATCUD7xMbm8eEKUdV5=J2kSk7BALfvBODDxKssCWB3mGDjw@mail.gmail.com
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In response to Re: Index-only scan performance regression  (Robert Haas <robertmhaas@gmail.com>)
List pgsql-hackers
On 2 February 2012 01:40, Robert Haas <robertmhaas@gmail.com> wrote:
> On Wed, Feb 1, 2012 at 7:44 PM, Robert Haas <robertmhaas@gmail.com> wrote:
>> So, I guess the trade-off here is that, since sinval messages aren't
>> processed immediately, we often won't notice the VM extension until
>> the next statement starts, whereas with the current implementation, we
>> notice it right away.  On the other hand, noticing it right away is
>> costing us a system call or two per tuple.  So on further thought, I
>> think we should do this.
>

Yes, that's a nice summary.

> Patch committed.  I moved the smgr inval to after the actual extension
> is done, which seems superior, and adjusted the comments slightly.
>

Thanks.

Regards,
Dean


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