Horton

Re: new heapcheck contrib module

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Mark Dilger <mark.dilger@enterprisedb.com>
Cc: Robert Haas <robertmhaas@gmail.com>, Peter Geoghegan <pg@bowt.ie>, "Andrey M. Borodin" <x4mmm@yandex-team.ru>, Stephen Frost <sfrost@snowman.net>, Michael Paquier <michael@paquier.xyz>, Amul Sul <sulamul@gmail.com>, Dilip Kumar <dilipbalaut@gmail.com>, Andres Freund <andres@anarazel.de>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2020-10-22T22:45:15Z
Lists: pgsql-hackers 
Mark Dilger <mark.dilger@enterprisedb.com> writes:
>> On Oct 22, 2020, at 2:06 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> Oh, wait a second.  ItemIdData has the flag bits in the middle:
>> meaning that for that particular bit pattern, one endianness
>> is going to see the flags as 01 (LP_NORMAL) and the other as 10
>> (LP_REDIRECT).

> Well, the issue is that on big-endian machines it is not reporting any
> corruption at all.  Are you sure the difference will be LP_NORMAL vs
> LP_REDIRECT?

[ thinks a bit harder... ]  Probably not.  The byte/bit string looks
the same either way, given that it's four repetitions of the same
byte value.  But which field is which will differ: we have either

	oooooooooooooooFFlllllllllllllll
	01110111011101110111011101110111

or

	lllllllllllllllFFooooooooooooooo
	01110111011101110111011101110111

So now I think this is a REDIRECT on either architecture, but the
offset and length fields have different values, causing the redirect
pointer to point to different places.  Maybe it happens to point
at a DEAD tuple in the big-endian case.

			regards, tom lane

Commits

  1. Add pg_amcheck, a CLI for contrib/amcheck.

  2. Refactor and generalize the ParallelSlot machinery.

  3. Generalize parallel slot result handling.

  4. Move some code from src/bin/scripts to src/fe_utils to permit reuse.

  5. Factor pattern-construction logic out of processSQLNamePattern.

  6. Doc: clean up verify_heapam() documentation.

  7. Fix more portability issues in new amcheck code.

  8. Fix portability issues in new amcheck test.

  9. Try to avoid a compiler warning about using fxid uninitialized.

  10. Extend amcheck to check heap pages.

  11. Adjust walsender usage of xlogreader, simplify APIs

  12. Improve checking of child pages in contrib/amcheck.

  13. Sanitize line pointers within contrib/amcheck.

  14. Fix possible sorting error when aborting use of abbreviated keys.