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Fix handling of non-upgraded B-tree metapages

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857f9c36 bumps B-tree metapage version while upgrade is performed "on the fly"
when needed. However, some asserts fired when old version metapage was
cached to rel->rd_amcache. Despite new metadata fields are never used from
rel->rd_amcache, that needs to be fixed. This patch introduces metadata
upgrade during its caching, which fills unavailable fields with their default
values. contrib/pageinspect is also patched to handle non-upgraded metapages
in the same way.

Author: Alexander Korotkov
This commit is contained in:
Teodor Sigaev 2018-04-05 17:56:00 +03:00
parent 01b88b4df5
commit 0a64b45152
2 changed files with 56 additions and 8 deletions
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17
contrib/pageinspect/btreefuncs.c
View File

@ -555,8 +555,21 @@ bt_metap(PG_FUNCTION_ARGS)
values[j++] = psprintf("%d", metad->btm_level);
values[j++] = psprintf("%d", metad->btm_fastroot);
values[j++] = psprintf("%d", metad->btm_fastlevel);
values[j++] = psprintf("%u", metad->btm_oldest_btpo_xact);
values[j++] = psprintf("%lf", metad->btm_last_cleanup_num_heap_tuples);
/*
* Get values of extended metadata if available, use default values
* otherwise.
*/
if (metad->btm_version == BTREE_VERSION)
{
values[j++] = psprintf("%u", metad->btm_oldest_btpo_xact);
values[j++] = psprintf("%lf", metad->btm_last_cleanup_num_heap_tuples);
}
else
{
values[j++] = "0";
values[j++] = "-1";
}
tuple = BuildTupleFromCStrings(TupleDescGetAttInMetadata(tupleDesc),
values);

47
src/backend/access/nbtree/nbtpage.c
View File

@ -33,6 +33,7 @@
#include "storage/predicate.h"
#include "utils/snapmgr.h"
static void _bt_cachemetadata(Relation rel, BTMetaPageData *metad);
static bool _bt_mark_page_halfdead(Relation rel, Buffer buf, BTStack stack);
static bool _bt_unlink_halfdead_page(Relation rel, Buffer leafbuf,
bool *rightsib_empty);
@ -105,6 +106,44 @@ _bt_upgrademetapage(Page page)
((char *) metad + sizeof(BTMetaPageData)) - (char *) page;
}
/*
* Cache metadata from meta page to rel->rd_amcache.
*/
static void
_bt_cachemetadata(Relation rel, BTMetaPageData *metad)
{
/* We assume rel->rd_amcache was already freed by caller */
Assert(rel->rd_amcache == NULL);
rel->rd_amcache = MemoryContextAlloc(rel->rd_indexcxt,
sizeof(BTMetaPageData));
/*
* Meta page should be of supported version (should be already checked by
* caller).
*/
Assert(metad->btm_version >= BTREE_MIN_VERSION &&
metad->btm_version <= BTREE_VERSION);
if (metad->btm_version == BTREE_VERSION)
{
/* Last version of meta-data, no need to upgrade */
memcpy(rel->rd_amcache, metad, sizeof(BTMetaPageData));
}
else
{
BTMetaPageData *cached_metad = (BTMetaPageData *) rel->rd_amcache;
/*
* Upgrade meta-data: copy available information from meta-page and
* fill new fields with default values.
*/
memcpy(rel->rd_amcache, metad, offsetof(BTMetaPageData, btm_oldest_btpo_xact));
cached_metad->btm_version = BTREE_VERSION;
cached_metad->btm_oldest_btpo_xact = InvalidTransactionId;
cached_metad->btm_last_cleanup_num_heap_tuples = -1.0;
}
}
/*
* _bt_update_meta_cleanup_info() -- Update cleanup-related information in
* the metapage.
@ -403,9 +442,7 @@ _bt_getroot(Relation rel, int access)
/*
* Cache the metapage data for next time
*/
rel->rd_amcache = MemoryContextAlloc(rel->rd_indexcxt,
sizeof(BTMetaPageData));
memcpy(rel->rd_amcache, metad, sizeof(BTMetaPageData));
_bt_cachemetadata(rel, metad);
/*
* We are done with the metapage; arrange to release it via first
@ -604,9 +641,7 @@ _bt_getrootheight(Relation rel)
/*
* Cache the metapage data for next time
*/
rel->rd_amcache = MemoryContextAlloc(rel->rd_indexcxt,
sizeof(BTMetaPageData));
memcpy(rel->rd_amcache, metad, sizeof(BTMetaPageData));
_bt_cachemetadata(rel, metad);
_bt_relbuf(rel, metabuf);
}