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

From: Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>
To: Dilip Kumar <dilipbalaut(at)gmail(dot)com>
Cc: Erik Rijkers <er(at)xs4all(dot)nl>, Kuntal Ghosh <kuntalghosh(dot)2007(at)gmail(dot)com>, Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com>, Michael Paquier <michael(at)paquier(dot)xyz>, Peter Eisentraut <peter(dot)eisentraut(at)2ndquadrant(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: PATCH: logical_work_mem and logical streaming of large in-progress transactions
Date: 2020-07-22 03:48:32
Message-ID: CAA4eK1L+TYON-jV1s=sJeOK2YOJkHu1oWc7pREx7i_hedWG7qg@mail.gmail.com
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On Mon, Jul 20, 2020 at 6:46 PM Dilip Kumar <dilipbalaut(at)gmail(dot)com> wrote:
>
> There was one warning in release mode in the last version in 0004 so
> attaching a new version.
>

Today, I was reviewing patch
v38-0001-WAL-Log-invalidations-at-command-end-with-wal_le and found a
small problem with it.

+ /*
+ * Execute the invalidations for xid-less transactions,
+ * otherwise, accumulate them so that they can be processed at
+ * the commit time.
+ */
+ if (!ctx->fast_forward)
+ {
+ if (TransactionIdIsValid(xid))
+ {
+ ReorderBufferAddInvalidations(reorder, xid, buf->origptr,
+ invals->nmsgs, invals->msgs);
+ ReorderBufferXidSetCatalogChanges(ctx->reorder, xid,
+ buf->origptr);
+ }

I think we need to set ReorderBufferXidSetCatalogChanges even when
ctx->fast-forward is true because we are dependent on that flag for
snapshot build (see SnapBuildCommitTxn). We are already doing the
same way in DecodeCommit where even though we skip adding
invalidations for fast-forward cases but we do set the flag to
indicate that this txn has catalog changes. Is there any reason to do
things differently here?

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

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