Re: PATCH: logical_work_mem and logical streaming of large in-progress transactions

On Mon, Jun 29, 2020 at 4:24 PM Dilip Kumar <dilipbalaut(at)gmail(dot)com> wrote:
>
> On Mon, Jun 22, 2020 at 4:30 PM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> >
> >
> > Other than above tests, can we somehow verify that the invalidations
> > generated at commit time are the same as what we do with this patch?
> > We have verified with individual commands but it would be great if we
> > can verify for the regression tests.
>
> I have verified this using a few random test cases. For verifying
> this I have made some temporary code changes with an assert as shown
> below. Basically, on DecodeCommit we call
> ReorderBufferAddInvalidations function only for an assert checking.
>
> -void
> ReorderBufferAddInvalidations(ReorderBuffer *rb, TransactionId xid,
> XLogRecPtr
> lsn, Size nmsgs,
> -
> SharedInvalidationMessage *msgs)
> +
> SharedInvalidationMessage *msgs, bool commit)
> {
> ReorderBufferTXN *txn;
>
> txn = ReorderBufferTXNByXid(rb, xid, true, NULL, lsn, true);
> -
> + if (commit)
> + {
> + Assert(txn->ninvalidations == nmsgs);
> + return;
> + }
>
> The result is that for a normal local test it works fine. But with
> regression suit, it hit an assert at many places because if the
> rollback of the subtransaction is involved then at commit time
> invalidation messages those are not logged whereas with command time
> invalidation those are logged.
>

Yeah, somehow, we need to ignore rollback to savepoint tests and
verify for others.

> As of now, I have only put assert on the count, if we need to verify
> the exact messages then we might need to somehow categories the
> invalidation messages because the ordering of the messages will not be
> the same. For testing this we will have to arrange them by category
> i.e relcahce, catcache and then we can compare them.
>

Can't we do this by verifying that each message at commit time exists
in the list of invalidation messages we have collected via processing
XLOG_XACT_INVALIDATIONS?

One additional question on patch
v30-0003-Extend-the-output-plugin-API-with-stream-methods:
+static void
+stream_commit_cb_wrapper(ReorderBuffer *cache, ReorderBufferTXN *txn,
+ XLogRecPtr apply_lsn)
{
..
..
+ state.report_location = apply_lsn;
..
..
+ ctx->write_location = apply_lsn;
..
}

Can't we name the last parameter as 'commit_lsn' as that is how
documentation in the patch spells it and it sounds more appropriate?
Also, is there a reason for assigning report_location and
write_location differently than what we do in commit_cb_wrapper?
Basically, assign those as txn->final_lsn and txn->end_lsn
respectively.

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