Re: Re: BUGFIX: standby disconnect can corrupt serialized reorder buffers

On 6 March 2018 at 09:58, Craig Ringer <craig(at)2ndquadrant(dot)com> wrote:

> On 5 March 2018 at 23:25, David Steele <david(at)pgmasters(dot)net> wrote:
>
>> Hi Craig,
>>
>> On 1/21/18 5:45 PM, Craig Ringer wrote:
>> > On 6 January 2018 at 08:28, Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org
>> > <mailto:alvherre(at)alvh(dot)no-ip(dot)org>> wrote:
>> >
>> > I think this should use ReadDirExtended with an elevel less than
>> ERROR,
>> > and do nothing.
>> >
>> > Why have strcmp(.) and strcmp(..)? These are going to be skipped
>> by the
>> > comparison to "xid" prefix anyway. Looks like strcmp processing
>> > power waste.
>> >
>> > Please don't use bare sprintf() -- upgrade to snprintf.
>> >
>> > With this coding, if I put a root-owned file "xidfoo" in a replslot
>> > directory, it will PANIC the server. Is that okay? Why not read
>> the
>> > file name with sscanf(), since we know the precise format it has?
>> Then
>> > we don't need to bother with random crap left around. Maybe a good
>> time
>> > to put the "xid-%u-lsn-%X-%X.snap" literal in a macro? I guess the
>> > rationale is that if you let random people put "xidfoo" files in
>> your
>> > replication slot dirs, you deserve a PANIC anyway, but I'm not sure.
>> >
>> > I'm happy to address those comments.
>> >
>> > The PANIC probably made sense when it was only done on startup, but not
>> > now it's at runtime.
>> >
>> > The rest is mainly retained from the prior code, but it's a good chance
>> > to make those changes.
>> This patch was marked Waiting on Author last December. Do you know when
>> you'll have a chance to provide an updated patch?
>>
>> Given that it's a bug fix it would be good to see a patch for this CF,
>> or very soon after.
>>
>>
> Thanks for the reminder. I'll address it today if I can.
>
>
Revised patch attached.

I have _not_ rewritten to use sscanf yet. I'll do that next, so you can
choose the fewer-changes patch for backpatching if desired.

--
Craig Ringer http://www.2ndQuadrant.com/
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