Subject: backup server core when redo btree_xlog_insert that type is XLOG_BTREE_INSERT_POST

From: yuansong <[email-masked]>
Date: Thu, 21 Nov 2024 23:02:46 +0800 (CST)

My database version is Postgresql 13.2 , backup server core when redo  a  btree_xlog_insert that type is XLOG_BTREE_INSERT_POST

#0 0x00002aab66695d86inmemmove ssse3 krom /lib64/libc.so.6

#1 0x00000000004f5574in_bt_swap_posting(newitem=0x125d998,oposting=0x2aabcd55dcc8ostingoff=13) at nbtdedup.c:796

#2 0x000000000050cf08 in btree_xlog_insert(isleaf=true,ismeta=false, posting=true,r ecord=0x122d7b8)at nbtxlog.c:224

43 0x000000000050ed53 in btree_redo(record=0x122d7b8) at nbtxlog.c:969

44 0x00000000005487b5 in StartupXLOG()at log.c:7320

#5 0x00000000008292ab in StartupProcessMain () atstartup.c:204

46 0x000000000055c916 in AuxiliaryProcessMain(argc=2,argv=0x7fff071f8a00) at bootstrap.c:443

#7 0x000000000082820d in StartChildProcess(type=StartupProcess) at postmaster.c:5492

48 0x00000000008236ce in PostmasterMain(argc=1argv=0x11fb2e0)at postmaster.c:1404

#9 0x00000000007398f7 in main(argc=1,argv=0x11fb2e0)at main.c:210

gdb) f 1

#1 0x00000000004f5574in btswap_posting(newitem=0x125d998,oposting=0x2aabcd55dcc8ostingoff=13) at nbtdedup.c.796

796

gdb) p((Size)((oposting)->t_info & 0x1FFF))         //oposting index tuple size 

 $12 = 16

gdb) p nhtids

$13= 17

gdb) p postingoff

$14=13

gdb) p nmovebytes

$15=18

IndexTuple

_bt_swap_posting(IndexTuple newitem, IndexTuple oposting, int postingoff)

{

intnhtids;

char   *replacepos;

char   *replaceposright;

Sizenmovebytes;

IndexTuplenposting;

nhtids = BTreeTupleGetNPosting(oposting);

       ===  nhtids = 17, postingoff = 13

Assert(_bt_posting_valid(oposting));

Assert(postingoff > 0 && postingoff < nhtids);

/*

* Move item pointers in posting list to make a gap for the new item's

* heap TID.  We shift TIDs one place to the right, losing original

* rightmost TID. (nmovebytes must not include TIDs to the left of

* postingoff, nor the existing rightmost/max TID that gets overwritten.)

*/

nposting = CopyIndexTuple(oposting);

===  IndexTupleSize(oposting) = 16, nposting memory size 16

replacepos = (char *) BTreeTupleGetPostingN(nposting, postingoff);

replaceposright = (char *) BTreeTupleGetPostingN(nposting, postingoff + 1);

nmovebytes = (nhtids - postingoff - 1) * sizeof(ItemPointerData);

memmove(replaceposright, replacepos, nmovebytes);

===core here,  nmovebytes = 18, for nposting size is 16, so here is  out of memory

}

Should nhtids be less than or equal to IndexTupleSize(oposting)?
 Why is nhtids larger than IndexTupleSize(oposting) ? I think there should be an error in the master host writing the wal log.
Does anyone know when this will happen?