Re: Minimal logical decoding on standbys

Hi,

On 2019-05-31 17:31:34 +0530, Amit Khandekar wrote:
> On Fri, 31 May 2019 at 11:08, Amit Khandekar  wrote:
> >
> > On Thu, 30 May 2019 at 20:13, Andres Freund  wrote:
> > Yes, it waits until there is a commit record, or (just tried) until a
> > checkpoint command.

That's fine with me.


> Is XLOG_RUNNING_XACTS record essential for the logical decoding to
> build a consistent snapshot ?

Yes.


> Since the restart_lsn is now ReplayRecPtr, there is no
> XLOG_RUNNING_XACTS record, and so the snapshot state is not yet
> SNAPBUILD_CONSISTENT. And so
> DecodingContextFindStartpoint()=>DecodingContextReady() never returns
> true, and hence DecodingContextFindStartpoint() goes in an infinite
> loop, until it gets XLOG_RUNNING_XACTS.

These seem like conflicting statements? Infinite loops don't terminate
until a record is logged?

Greetings,

Andres Freund