pg.ddx.io pgsql-admin@postgresql.org mailing list archive help / color / mirror / Atom feed From: Álvaro Herrera <alvherre@alvh.no-ip.org>
To: Sergey Aleynikov <sergey.aleynikov@gmail.com>
Cc: pgsql-admin@lists.postgresql.org
Subject: Re: Xmax precedes relation freeze threshold errors
Date: Fri, 17 Jun 2022 11:53:05 +0200
Message-ID: <20220617095305.dhu6yk5po7b4qrih@alvherre.pgsql> (raw )
In-Reply-To: <CAKNj8S27f1PUQnREQnvwemdrvPAQ_u+Q_+KuhtKmi+Be=Oz=uQ@mail.gmail.com >
On 2022-Jun-16, Sergey Aleynikov wrote:
> (verify_heapam before)
> blkno | offnum | attnum | msg
> -------+--------+--------+-----------------------------------------------------------------
> 20365 | 8 | | xmax 1965224948 precedes relation freeze threshold 1:1914858032
> 20365 | 12 | | xmin 1965224948 precedes relation freeze threshold 1:1914858032
> (2 rows)
Hmm, well, these errors make no sense, because 1965224948 is definitely
not earlier than the stated threshold of 1914858032. There might be a
bug in the amcheck conversion of the epochless XID value to FullXid, or
in the comparison functions.
For the record, the values for this page are below. For (20365,8) the
infomask is 0x2102 which is HEAP_UPDATED | HEAP_XMIN_COMMITTED; there's
no bit for Xmax. The next one in the chain is the other
complained-about tuple, (20365,12) which has a matching Xmin (no
surprise there) and the infomask is 0x2092 which is HEAP_UPDATED |
HEAP_XMAX_LOCK_ONLY | HEAP_XMAX_KEYSHR_LOCK. So this is a tuple that
was updated and then the new version was used by SELECT FOR KEY SHARE.
Nothing strange here.
lp | lp_off | lp_flags | lp_len | t_xmin | t_xmax | t_field3 | t_ctid | t_infomask2 | t_infomask | t_hoff | t_bits | t_oid | t_data
----+--------+----------+--------+------------+------------+----------+------------+-------------+------------+--------+--------+-------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1 | 25 | 2 | 0 | | | | | | | | | |
2 | 4504 | 1 | 204 | 1965224930 | 1965224938 | 6 | (20365,8) | 57347 | 9474 | 24 | | | \016\301\177\005\000\000\000\000\300\271\261\265\215\204\002\000\220\002\000\000[[1,0,1655367415],[2,0,1655368111],[3,0,1655316514],[4,1,1345141307],[7,0,1655368111],[10,46,1655368114],[12,0,1655316561],[13,2,1602489365],[16,20,1655368127]]
3 | 8040 | 1 | 147 | 1852898199 | 0 | 38 | (20365,3) | 3 | 11010 | 24 | | | \205<\207\005\000\000\000\000\200\317f\023/\202\002\000\327[[1,0,1649925421],[2,3,1652762654],[4,1,1336885001],[7,0,1652762654],[10,49,1649925346],[16,0,1649925383]]
4 | 27 | 2 | 0 | | | | | | | | | |
5 | 7768 | 1 | 272 | 1964963817 | 1964963897 | 7 | (20365,5) | 40963 | 10690 | 24 | | | \035(\345\005\000\000\000\000\300\301\017\300\213\204\002\000\240\003\000\000[[1,0,1655356016],[2,0,1655355988],[3,0,1655359711],[4,1,1318680670],[6,1,1580191566],[7,0,1655355987],[8,4,1580191566],[9,3,1580191566],[10,39,1655358356],[12,1,1580280953],[13,3,1580191566],[14,0,1580191566],[16,0,1594455141]]
6 | 7488 | 1 | 273 | 1904288297 | 0 | 7 | (20365,6) | 32771 | 11010 | 24 | | | H\032\311\005\000\000\000\000\3007\252\326`\203\002\000\244\003\000\000[[1,1,1638359432],[2,8,1654075863],[3,0,1654075895],[4,1,1411368668],[6,0,1643527342],[7,0,1654075863],[8,4,1586241825],[9,3,1586241825],[10,48,1653909745],[12,1,1586241825],[13,3,1586241825],[14,0,1586241825],[16,30,1586241825]]
7 | 32 | 2 | 0 | | | | | | | | | |
8 | 4296 | 1 | 204 | 1965224938 | 1965224948 | 6 | (20365,12) | 57347 | 8450 | 24 | | | \016\301\177\005\000\000\000\000\300\271\261\265\215\204\002\000\220\002\000\000[[1,0,1655367415],[2,0,1655368111],[3,0,1655316514],[4,1,1345141307],[7,0,1655368111],[10,46,1655368114],[12,0,1655316561],[13,2,1602489365],[16,19,1655368127]]
9 | 6 | 2 | 0 | | | | | | | | | |
10 | 29 | 2 | 0 | | | | | | | | | |
11 | 7208 | 1 | 273 | 1965056934 | 1965056934 | 7 | (20365,11) | 32771 | 10642 | 24 | | | \377\232\310\005\000\000\000\000\200\271\334q\214\204\002\000\244\003\000\000[[1,0,1655361162],[2,5,1655361996],[3,0,1655362694],[4,1,1358874131],[6,0,1655055632],[7,0,1655361158],[8,4,1580366031],[9,3,1639915217],[10,46,1655361947],[12,1,1653134366],[13,3,1580366031],[14,0,1580366031],[16,30,1580366031]]
12 | 4088 | 1 | 204 | 1965224948 | 1965224948 | 6 | (20365,12) | 32771 | 8338 | 24 | | | \016\301\177\005\000\000\000\000\000\374\300\265\215\204\002\000\220\002\000\000[[1,0,1655367415],[2,0,1655368111],[3,0,1655316514],[4,1,1345141307],[7,0,1655368111],[10,46,1655368114],[12,0,1655316561],[13,2,1602489365],[16,18,1655368128]]
13 | 7160 | 1 | 43 | 1957335917 | 1964638027 | 1 | (20365,13) | 8195 | 2498 | 24 | | | \310jo\007\000\000\000\000\200\027k\264b\204\002\000\007[]
14 | 16 | 2 | 0 | | | | | | | | | |
15 | 0 | 0 | 0 | | | | | | | | | |
16 | 6880 | 1 | 273 | 1965223751 | 1965223751 | 8 | (20365,16) | 32771 | 10642 | 24 | | | \347\243\236\005\000\000\000\000\300h\214\263\215\204\002\000\244\003\000\000[[1,0,1655240440],[2,9,1655368091],[3,0,1654972875],[4,1,1397413995],[6,0,1654175940],[7,0,1655368091],[8,4,1582557307],[9,3,1582557307],[10,47,1654197675],[12,1,1629279335],[13,3,1587923475],[14,0,1582557307],[16,30,1648131697]]
17 | 0 | 0 | 0 | | | | | | | | | |
18 | 0 | 0 | 0 | | | | | | | | | |
19 | 0 | 0 | 0 | | | | | | | | | |
20 | 0 | 0 | 0 | | | | | | | | | |
21 | 0 | 0 | 0 | | | | | | | | | |
22 | 0 | 0 | 0 | | | | | | | | | |
23 | 0 | 0 | 0 | | | | | | | | | |
24 | 0 | 0 | 0 | | | | | | | | | |
25 | 6640 | 1 | 238 | 1490075747 | 0 | 5 | (20365,25) | 32771 | 11010 | 24 | | | \373\021J\007\000\000\000\000\300\207\236\331|z\002\000\030\003\000\000[[1,0,1644300599],[2,10,1643357339],[3,4,1643109769],[6,0,1643357339],[7,0,1643365735],[8,4,1643357339],[9,3,1643357339],[12,0,1643360113],[13,3,1643108769],[14,0,1643357339],[16,30,1643357339]]
26 | 0 | 0 | 0 | | | | | | | | | |
27 | 6360 | 1 | 273 | 1962697004 | 1962697004 | 7 | (20365,27) | 32771 | 10642 | 24 | | | \3342\251\005\000\000\000\000\200\020\230\276x\204\002\000\244\003\000\000[[1,1,1655183659],[2,9,1655278082],[3,4,1655217231],[4,1,1646965839],[6,0,1655275445],[7,0,1655278082],[8,4,1636371136],[9,3,1636371136],[10,46,1655182361],[12,1,1648303165],[13,3,1636371136],[14,0,1636371136],[16,30,1636371136]]
28 | 0 | 0 | 0 | | | | | | | | | |
29 | 6080 | 1 | 273 | 1964885708 | 1964885708 | 9 | (20365,29) | 32771 | 10642 | 24 | | | y\031\300\006\000\000\000\000\300=&.\213\204\002\000\244\003\000\000[[1,0,1655356874],[2,0,1655356785],[3,3,1655356828],[4,0,1607932548],[6,0,1593701110],[7,0,1655356785],[8,4,1589636764],[9,3,1589636764],[10,45,1655357263],[12,0,1655223006],[13,2,1633191479],[14,0,1589636764],[16,22,1655285002]]
30 | 5 | 2 | 0 | | | | | | | | | |
31 | 6032 | 1 | 43 | 1529256935 | 0 | 1 | (20365,31) | 3 | 2818 | 24 | | | z\315N\007\000\000\000\000\000\207\037)0{\002\000\007[]
32 | 5752 | 1 | 273 | 1964761973 | 1964761973 | 7 | (20365,32) | 32771 | 10642 | 24 | | | \377\020\322\005\000\000\000\000\000d\303+\212\204\002\000\244\003\000\000[[1,1,1635340514],[2,8,1655352336],[3,0,1655352928],[4,1,1324578627],[6,0,1652362638],[7,0,1655352336],[8,4,1580283680],[9,3,1580283680],[10,49,1655321899],[12,1,1623273443],[13,3,1580283680],[14,0,1580283680],[16,30,1580283680]]
33 | 0 | 0 | 0 | | | | | | | | | |
34 | 0 | 0 | 0 | | | | | | | | | |
35 | 5472 | 1 | 273 | 1962530750 | 1962530750 | 9 | (20365,35) | 32771 | 10642 | 24 | | | "\273o\005\000\000\000\000\200\024\276\206w\204\002\000\244\003\000\000[[1,0,1655272251],[2,6,1655272847],[3,0,1655110969],[4,1,1364884674],[6,0,1649045620],[7,0,1655272847],[8,4,1621844466],[9,3,1621844466],[10,49,1655272850],[12,1,1635832362],[13,3,1621821962],[14,0,1621844466],[16,30,1621844466]]
36 | 5264 | 1 | 204 | 1965224703 | 1965224917 | 6 | (20365,38) | 57347 | 9474 | 24 | | | \016\301\177\005\000\000\000\000\300\2477\265\215\204\002\000\220\002\000\000[[1,0,1655367415],[2,0,1655368111],[3,0,1655316514],[4,1,1345141307],[7,0,1655368111],[10,46,1655368114],[12,0,1655316561],[13,2,1602489365],[16,23,1655368119]]
37 | 5128 | 1 | 129 | 1964847563 | 1964847563 | 7 | (20365,37) | 32771 | 10642 | 24 | | | \201A\250\005\000\000\000\000\300\215\253\345\212\204\002\000\263[[1,0,1655355920],[2,6,1655355999],[3,0,1655356047],[7,0,1655355997],[10,46,1655356007]]
38 | 4920 | 1 | 204 | 1965224917 | 1965224925 | 6 | (20365,39) | 57347 | 9474 | 24 | | | \016\301\177\005\000\000\000\000\200w\242\265\215\204\002\000\220\002\000\000[[1,0,1655367415],[2,0,1655368111],[3,0,1655316514],[4,1,1345141307],[7,0,1655368111],[10,46,1655368114],[12,0,1655316561],[13,2,1602489365],[16,22,1655368126]]
39 | 4712 | 1 | 204 | 1965224925 | 1965224930 | 6 | (20365,2) | 57347 | 9474 | 24 | | | \016\301\177\005\000\000\000\000\200w\242\265\215\204\002\000\220\002\000\000[[1,0,1655367415],[2,0,1655368111],[3,0,1655316514],[4,1,1345141307],[7,0,1655368111],[10,46,1655368114],[12,0,1655316561],[13,2,1602489365],[16,21,1655368126]]
40 | 0 | 0 | 0 | | | | | | | | | |
41 | 0 | 0 | 0 | | | | | | | | | |
42 | 0 | 0 | 0 | | | | | | | | | |
43 | 0 | 0 | 0 | | | | | | | | | |
44 | 0 | 0 | 0 | | | | | | | | | |
45 | 35 | 2 | 0 | | | | | | | | | |
46 | 0 | 0 | 0 | | | | | | | | | |
47 | 37 | 2 | 0 | | | | | | | | | |
48 | 11 | 2 | 0 | | | | | | | | | |
49 | 0 | 0 | 0 | | | | | | | | | |
50 | 0 | 0 | 0 | | | | | | | | | |
51 | 36 | 2 | 0 | | | | | | | | | |
(51 rows)
--
Álvaro Herrera 48°01'N 7°57'E — https://www.EnterpriseDB.com/
"Always assume the user will do much worse than the stupidest thing
you can imagine." (Julien PUYDT)
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Cc: alvherre@alvh.no-ip.org, sergey.aleynikov@gmail.com, pgsql-admin@lists.postgresql.org
Subject: Re: Xmax precedes relation freeze threshold errors
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