Re: logical decoding vs. VACUUM FULL / CLUSTER on table with TOAST-ed data

On 11/28/18 3:31 AM, Andres Freund wrote:
> Hi,
>
> On 2018-11-28 03:06:58 +0100, Petr Jelinek wrote:
>> On 28/11/2018 02:14, Andres Freund wrote:
>>> On 2018-11-28 02:04:18 +0100, Tomas Vondra wrote:
>>>> Pushed and backpatched to 9.4- (same as e9edc1ba).
>>>
>>> Backpatching seems on the more aggressive end of things for an
>>> optimization. Could you at least announce that beforehand next time?
>>>
>>
>> Well, it may be optimization, but from what I've seen the problems
>> arising from this can easily prevent logical replication from working
>> altogether as reorder buffer hits OOM on bigger tables. So ISTM that it
>> does warrant backpatch.
>
> I think that's a fair argument to be made. But it should be made
> both before the commit and in the commit message.
>

Understood. I thought I stated the intent to backpatch when announcing
I'll push it this week, but clearly that did not happen. Oops :-(

That being said, I see this more like a bugfix than an optimization,
because (as Petr already stated) rewrite of any sufficiently large table
can irreparably break the replication. So it's not just slower, it dies.

regards

--
Tomas Vondra http://www.2ndQuadrant.com
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