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Deduplicate choice of horizon for a relation procarray.c. 

5a1e1d8302 was a minimal bug fix for dc7420c2c9. To avoid future bugs of
that kind, deduplicate the choice of a relation's horizon into a new helper,
GlobalVisHorizonKindForRel().

As the code in question was only introduced in dc7420c2c9 it seems worth
backpatching this change as well, otherwise 14 will look different from all
other branches.

A different approach to this was suggested by Matthias van de Meent.

Author: Andres Freund
Discussion: https://postgr.es/m/20210621122919.2qhu3pfugxxp3cji@alap3.anarazel.de
Backpatch: 14, like 5a1e1d8302
This commit is contained in:
Andres Freund 2021-07-24 20:14:03 -07:00
parent 6310809c4a
commit d9d8aa9bb9
1 changed files with 66 additions and 35 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

101
src/backend/storage/ipc/procarray.c
View File

@ -246,6 +246,17 @@ typedef struct ComputeXidHorizonsResult
} ComputeXidHorizonsResult;
/*
* Return value for GlobalVisHorizonKindForRel().
*/
typedef enum GlobalVisHorizonKind
{
VISHORIZON_SHARED,
VISHORIZON_CATALOG,
VISHORIZON_DATA,
VISHORIZON_TEMP
} GlobalVisHorizonKind;
static ProcArrayStruct *procArray;
@ -1952,6 +1963,33 @@ ComputeXidHorizons(ComputeXidHorizonsResult *h)
GlobalVisUpdateApply(h);
}
/*
* Determine what kind of visibility horizon needs to be used for a
* relation. If rel is NULL, the most conservative horizon is used.
*/
static inline GlobalVisHorizonKind
GlobalVisHorizonKindForRel(Relation rel)
{
/*
* Other relkkinds currently don't contain xids, nor always the necessary
* logical decoding markers.
*/
Assert(!rel ||
rel->rd_rel->relkind == RELKIND_RELATION ||
rel->rd_rel->relkind == RELKIND_MATVIEW ||
rel->rd_rel->relkind == RELKIND_TOASTVALUE);
if (rel == NULL || rel->rd_rel->relisshared || RecoveryInProgress())
return VISHORIZON_SHARED;
else if (IsCatalogRelation(rel) ||
RelationIsAccessibleInLogicalDecoding(rel))
return VISHORIZON_CATALOG;
else if (!RELATION_IS_LOCAL(rel))
return VISHORIZON_DATA;
else
return VISHORIZON_TEMP;
}
/*
* Return the oldest XID for which deleted tuples must be preserved in the
* passed table.
@ -1970,16 +2008,20 @@ GetOldestNonRemovableTransactionId(Relation rel)
ComputeXidHorizons(&horizons);
/* select horizon appropriate for relation */
if (rel == NULL || rel->rd_rel->relisshared || RecoveryInProgress())
return horizons.shared_oldest_nonremovable;
else if (IsCatalogRelation(rel) ||
RelationIsAccessibleInLogicalDecoding(rel))
return horizons.catalog_oldest_nonremovable;
else if (RELATION_IS_LOCAL(rel))
return horizons.temp_oldest_nonremovable;
else
return horizons.data_oldest_nonremovable;
switch (GlobalVisHorizonKindForRel(rel))
{
case VISHORIZON_SHARED:
return horizons.shared_oldest_nonremovable;
case VISHORIZON_CATALOG:
return horizons.catalog_oldest_nonremovable;
case VISHORIZON_DATA:
return horizons.data_oldest_nonremovable;
case VISHORIZON_TEMP:
return horizons.temp_oldest_nonremovable;
}
/* just to prevent compiler warnings */
return InvalidTransactionId;
}
/*
@ -3986,38 +4028,27 @@ DisplayXidCache(void)
GlobalVisState *
GlobalVisTestFor(Relation rel)
{
bool need_shared;
bool need_catalog;
GlobalVisState *state;
GlobalVisState *state = NULL;
/* XXX: we should assert that a snapshot is pushed or registered */
Assert(RecentXmin);
if (!rel)
need_shared = need_catalog = true;
else
switch (GlobalVisHorizonKindForRel(rel))
{
/*
* Other kinds currently don't contain xids, nor always the necessary
* logical decoding markers.
*/
Assert(rel->rd_rel->relkind == RELKIND_RELATION ||
rel->rd_rel->relkind == RELKIND_MATVIEW ||
rel->rd_rel->relkind == RELKIND_TOASTVALUE);
need_shared = rel->rd_rel->relisshared || RecoveryInProgress();
need_catalog = IsCatalogRelation(rel) || RelationIsAccessibleInLogicalDecoding(rel);
case VISHORIZON_SHARED:
state = &GlobalVisSharedRels;
break;
case VISHORIZON_CATALOG:
state = &GlobalVisCatalogRels;
break;
case VISHORIZON_DATA:
state = &GlobalVisDataRels;
break;
case VISHORIZON_TEMP:
state = &GlobalVisTempRels;
break;
}
if (need_shared)
state = &GlobalVisSharedRels;
else if (need_catalog)
state = &GlobalVisCatalogRels;
else if (RELATION_IS_LOCAL(rel))
state = &GlobalVisTempRels;
else
state = &GlobalVisDataRels;
Assert(FullTransactionIdIsValid(state->definitely_needed) &&
FullTransactionIdIsValid(state->maybe_needed));