From: | Peter Geoghegan <pg(at)bowt(dot)ie> |
---|---|
To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | Justin Pryzby <pryzby(at)telsasoft(dot)com>, James Coleman <jtc331(at)gmail(dot)com>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>, Tomas Vondra <tomas(dot)vondra(at)postgresql(dot)org>, Alexander Korotkov <a(dot)korotkov(at)postgrespro(dot)ru> |
Subject: | Re: 13dev failed assert: comparetup_index_btree(): ItemPointer values should never be equal |
Date: | 2020-07-28 22:09:58 |
Message-ID: | CAH2-Wznby6Yho4hi_z53eeurQrLC1PccH+zyoBtOBnd8sA-K9A@mail.gmail.com |
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On Tue, Jul 28, 2020 at 2:46 PM Peter Geoghegan <pg(at)bowt(dot)ie> wrote:
> The fact remains that this function (originally known as
> IndexBuildHeapScan(), now heapam_index_build_range_scan()) did not
> care about whether or not the index is unique for about 3 years
> (excluding the tupleIsAlive stuff, which was always there, even before
> HOT). The original HOT commit (commit 282d2a03dd3) said nothing about
> unique indexes in the relevant path (the HEAPTUPLE_INSERT_IN_PROGRESS
> + !TransactionIdIsCurrentTransactionId() "concurrent system catalog
> insert" path). The need to wait here really did seem to be all about
> not getting duplicate TIDs (i.e. respecting the basic HOT invariant)
> back in 2007.
I mentioned that the unique index aspect was added by commit 1ddc2703
in 2010 (the new-style VACUUM FULL deadlock commit that added the "if
(checking_uniqueness)" condition). Turns out that that had bugs that
were fixed in 2011's commit 520bcd9c9bb (at least I think so based on
a reading of the latter commit's commit message) -- though those were
in the DELETE_IN_PROGRESS case.
Perhaps 2011's commit 520bcd9c9bb missed similar
HEAPTUPLE_INSERT_IN_PROGRESS issues that manifest themselves within
Justin's test case now?
--
Peter Geoghegan
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