| From: | Joachim Wieland <joe(at)mcknight(dot)de> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | Simon Riggs <simon(at)2ndquadrant(dot)com>, Andres Freund <andres(at)anarazel(dot)de>, pgsql-hackers(at)postgresql(dot)org, Kris Jurka <books(at)ejurka(dot)com>, Fujii Masao <masao(dot)fujii(at)gmail(dot)com> |
| Subject: | Re: Hot Standy introduced problem with query cancel behavior |
| Date: | 2010-01-07 16:48:02 |
| Message-ID: | dc7b844e1001070848p63eab52bl1d21b86e4249c66c@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Thu, Jan 7, 2010 at 4:23 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Joachim Wieland <joe(at)mcknight(dot)de> writes:
>> As there were so many boolean SomethingCancelPending variables I changed them
>> to be bitmasks and merged all of them into a single variable.
>
> This seems like a truly horrid idea, because those variables are set by
> signal handlers. A bitmask cannot be manipulated atomically, so you
> have almost certainly introduced race-condition bugs.
True... However there are just a few places where the patch uses
bitmasks for modification of the variable. As Simon seems to be
working on this currently anyway, I'll leave it to him to either keep
the 5 boolean variables or do some mutual exclusion as in
HandleNotifyInterrupt() (or do something completely different).
Joachim
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