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Fix amcheck child check pg_upgrade bug.

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Commit d114cc53 overlooked the fact that pg_upgrade'd B-Tree indexes
have leaf page high keys whose offset numbers do not match the one from
the copy of the tuple one level up (the copy stored with a downlink for
leaf page's right sibling page).  This led to false positive reports of
corruption from bt_index_parent_check() when it was called to verify a
pg_upgrade'd index.

To fix, skip comparing the offset number on pg_upgrade'd B-Tree indexes.

Author: Anastasia Lubennikova <a.lubennikova@postgrespro.ru>
Author: Peter Geoghegan <pg@bowt.ie>
Reported-By: Andrew Bille <andrewbille@gmail.com>
Diagnosed-By: Anastasia Lubennikova <a.lubennikova@postgrespro.ru>
Bug: #16619
Discussion: https://postgr.es/m/16619-aaba10f83fdc1c3c@postgresql.org
Backpatch: 13-, where child check was enhanced.
This commit is contained in:
Peter Geoghegan 2020-09-16 10:42:30 -07:00
parent e5fac1cb19
commit aac80bfcdd
1 changed files with 28 additions and 6 deletions
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30
contrib/amcheck/verify_nbtree.c
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@ -1752,14 +1752,36 @@ bt_right_page_check_scankey(BtreeCheckState *state)
* this function is capable to compare pivot keys on different levels.
*/
static bool
bt_pivot_tuple_identical(IndexTuple itup1, IndexTuple itup2)
bt_pivot_tuple_identical(bool heapkeyspace, IndexTuple itup1, IndexTuple itup2)
{
if (IndexTupleSize(itup1) != IndexTupleSize(itup2))
return false;
if (heapkeyspace)
{
/*
* Offset number will contain important information in heapkeyspace
* indexes: the number of attributes left in the pivot tuple following
* suffix truncation. Don't skip over it (compare it too).
*/
if (memcmp(&itup1->t_tid.ip_posid, &itup2->t_tid.ip_posid,
IndexTupleSize(itup1) - offsetof(ItemPointerData, ip_posid)) != 0)
IndexTupleSize(itup1) -
offsetof(ItemPointerData, ip_posid)) != 0)
return false;
}
else
{
/*
* Cannot rely on offset number field having consistent value across
* levels on pg_upgrade'd !heapkeyspace indexes. Compare contents of
* tuple starting from just after item pointer (i.e. after block
* number and offset number).
*/
if (memcmp(&itup1->t_info, &itup2->t_info,
IndexTupleSize(itup1) -
offsetof(IndexTupleData, t_info)) != 0)
return false;
}
return true;
}
@ -1913,7 +1935,7 @@ bt_child_highkey_check(BtreeCheckState *state,
rightsplit = P_INCOMPLETE_SPLIT(opaque);
/*
* If we visit page with high key, check that it is be equal to the
* If we visit page with high key, check that it is equal to the
* target key next to corresponding downlink.
*/
if (!rightsplit && !P_RIGHTMOST(opaque))
@ -2007,7 +2029,7 @@ bt_child_highkey_check(BtreeCheckState *state,
itup = state->lowkey;
}
if (!bt_pivot_tuple_identical(highkey, itup))
if (!bt_pivot_tuple_identical(state->heapkeyspace, highkey, itup))
{
ereport(ERROR,
(errcode(ERRCODE_INDEX_CORRUPTED),