Re: logical replication empty transactions

On Wed, Mar 4, 2020 at 7:17 AM Euler Taveira
<euler(dot)taveira(at)2ndquadrant(dot)com> wrote:
>
> On Tue, 3 Mar 2020 at 05:24, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
>>
>>
>> Another idea could be that we stream the transaction after some
>> threshold number (say 100 or anything we think is reasonable) of empty
>> xacts. This will reduce the traffic without tinkering with the core
>> design too much.
>>
>>
> Amit, I suggest an interval to control this setting. Time is something we have control; transactions aren't (depending on workload). pg_stat_replication query interval usually is not milliseconds, however, you can execute thousands of transactions in a second. If we agree on that idea I can add it to the patch.
>

Do you mean to say that if for some threshold interval we didn't
stream any transaction, then we can send the next empty transaction to
the subscriber? If so, then isn't it possible that the empty xacts
happen irregularly after the specified interval and then we still end
up sending them all. I might be missing something here, so can you
please explain your idea in detail? Basically, how will it work and
how will it solve the problem.

--
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com