return entry;
}
-/*
- * Returns true if the given index consists only of expressions such as:
- * CREATE INDEX idx ON table(foo(col));
- *
- * Returns false even if there is one column reference:
- * CREATE INDEX idx ON table(foo(col), col_2);
- */
-static bool
-IsIndexOnlyOnExpression(IndexInfo *indexInfo)
-{
- for (int i = 0; i < indexInfo->ii_NumIndexKeyAttrs; i++)
- {
- AttrNumber attnum = indexInfo->ii_IndexAttrNumbers[i];
-
- if (AttributeNumberIsValid(attnum))
- return false;
- }
-
- return true;
-}
-
-/*
- * Returns true if the attrmap contains the leftmost column of the index.
- * Otherwise returns false.
- *
- * attrmap is a map of local attributes to remote ones. We can consult this
- * map to check whether the local index attribute has a corresponding remote
- * attribute.
- */
-static bool
-RemoteRelContainsLeftMostColumnOnIdx(IndexInfo *indexInfo, AttrMap *attrmap)
-{
- AttrNumber keycol;
-
- Assert(indexInfo->ii_NumIndexAttrs >= 1);
-
- keycol = indexInfo->ii_IndexAttrNumbers[0];
- if (!AttributeNumberIsValid(keycol))
- return false;
-
- if (attrmap->maplen <= AttrNumberGetAttrOffset(keycol))
- return false;
-
- return attrmap->attnums[AttrNumberGetAttrOffset(keycol)] >= 0;
-}
-
/*
* Returns the oid of an index that can be used by the apply worker to scan
- * the relation. The index must be btree or hash, non-partial, and the leftmost
- * field must be a column (not an expression) that references the remote
- * relation column. These limitations help to keep the index scan similar
- * to PK/RI index scans.
- *
- * Note that the limitations of index scans for replica identity full only
- * adheres to a subset of the limitations of PK/RI. For example, we support
- * columns that are marked as [NULL] or we are not interested in the [NOT
- * DEFERRABLE] aspect of constraints here. It works for us because we always
- * compare the tuples for non-PK/RI index scans. See
- * RelationFindReplTupleByIndex().
- *
- * XXX: See IsIndexUsableForReplicaIdentityFull() to know the challenges in
- * supporting indexes other than btree and hash. For partial indexes, the
- * required changes are likely to be larger. If none of the tuples satisfy
- * the expression for the index scan, we fall-back to sequential execution,
- * which might not be a good idea in some cases.
+ * the relation.
*
* We expect to call this function when REPLICA IDENTITY FULL is defined for
* the remote relation.
{
Oid idxoid = lfirst_oid(lc);
bool isUsableIdx;
- bool containsLeftMostCol;
Relation idxRel;
IndexInfo *idxInfo;
idxRel = index_open(idxoid, AccessShareLock);
idxInfo = BuildIndexInfo(idxRel);
- isUsableIdx = IsIndexUsableForReplicaIdentityFull(idxInfo);
- containsLeftMostCol =
- RemoteRelContainsLeftMostColumnOnIdx(idxInfo, attrmap);
+ isUsableIdx = IsIndexUsableForReplicaIdentityFull(idxInfo, attrmap);
index_close(idxRel, AccessShareLock);
/* Return the first eligible index found */
- if (isUsableIdx && containsLeftMostCol)
+ if (isUsableIdx)
return idxoid;
}
}
/*
- * Returns true if the index is usable for replica identity full. For details,
- * see FindUsableIndexForReplicaIdentityFull.
+ * Returns true if the index is usable for replica identity full.
*
- * Currently, only Btree and Hash indexes can be returned as usable. This
- * is due to following reasons:
+ * The index must be btree or hash, non-partial, and the leftmost field must be
+ * a column (not an expression) that references the remote relation column. These
+ * limitations help to keep the index scan similar to PK/RI index scans.
+ *
+ * attrmap is a map of local attributes to remote ones. We can consult this
+ * map to check whether the local index attribute has a corresponding remote
+ * attribute.
+ *
+ * Note that the limitations of index scans for replica identity full only
+ * adheres to a subset of the limitations of PK/RI. For example, we support
+ * columns that are marked as [NULL] or we are not interested in the [NOT
+ * DEFERRABLE] aspect of constraints here. It works for us because we always
+ * compare the tuples for non-PK/RI index scans. See
+ * RelationFindReplTupleByIndex().
+ *
+ * The reasons why only Btree and Hash indexes can be considered as usable are:
*
* 1) Other index access methods don't have a fixed strategy for equality
* operation. Refer get_equal_strategy_number_for_am().
*
* XXX: Note that BRIN and GIN indexes do not implement "amgettuple" which
* will be used later to fetch the tuples. See RelationFindReplTupleByIndex().
+ *
+ * XXX: To support partial indexes, the required changes are likely to be larger.
+ * If none of the tuples satisfy the expression for the index scan, we fall-back
+ * to sequential execution, which might not be a good idea in some cases.
*/
bool
-IsIndexUsableForReplicaIdentityFull(IndexInfo *indexInfo)
+IsIndexUsableForReplicaIdentityFull(IndexInfo *indexInfo, AttrMap *attrmap)
{
+ AttrNumber keycol;
+
/* Ensure that the index access method has a valid equal strategy */
if (get_equal_strategy_number_for_am(indexInfo->ii_Am) == InvalidStrategy)
return false;
+
+ /* The index must not be a partial index */
if (indexInfo->ii_Predicate != NIL)
return false;
- if (IsIndexOnlyOnExpression(indexInfo))
+
+ Assert(indexInfo->ii_NumIndexAttrs >= 1);
+
+ /* The leftmost index field must not be an expression */
+ keycol = indexInfo->ii_IndexAttrNumbers[0];
+ if (!AttributeNumberIsValid(keycol))
+ return false;
+
+ /*
+ * And the leftmost index field must reference the remote relation column.
+ * This is because if it doesn't, the sequential scan is favorable over
+ * index scan in most cases.
+ */
+ if (attrmap->maplen <= AttrNumberGetAttrOffset(keycol) ||
+ attrmap->attnums[AttrNumberGetAttrOffset(keycol)] < 0)
return false;
#ifdef USE_ASSERT_CHECKING
#include <sys/stat.h>
#include <unistd.h>
+#include "access/genam.h"
#include "access/table.h"
#include "access/tableam.h"
#include "access/twophase.h"
ResultRelInfo *relinfo,
TupleTableSlot *remoteslot,
Oid localindexoid);
-static bool FindReplTupleInLocalRel(EState *estate, Relation localrel,
+static bool FindReplTupleInLocalRel(ApplyExecutionData *edata, Relation localrel,
LogicalRepRelation *remoterel,
Oid localidxoid,
TupleTableSlot *remoteslot,
EvalPlanQualInit(&epqstate, estate, NULL, NIL, -1, NIL);
ExecOpenIndices(relinfo, false);
- found = FindReplTupleInLocalRel(estate, localrel,
+ found = FindReplTupleInLocalRel(edata, localrel,
&relmapentry->remoterel,
localindexoid,
remoteslot, &localslot);
EvalPlanQualInit(&epqstate, estate, NULL, NIL, -1, NIL);
ExecOpenIndices(relinfo, false);
- found = FindReplTupleInLocalRel(estate, localrel, remoterel, localindexoid,
+ found = FindReplTupleInLocalRel(edata, localrel, remoterel, localindexoid,
remoteslot, &localslot);
/* If found delete it. */
* Local tuple, if found, is returned in '*localslot'.
*/
static bool
-FindReplTupleInLocalRel(EState *estate, Relation localrel,
+FindReplTupleInLocalRel(ApplyExecutionData *edata, Relation localrel,
LogicalRepRelation *remoterel,
Oid localidxoid,
TupleTableSlot *remoteslot,
TupleTableSlot **localslot)
{
+ EState *estate = edata->estate;
bool found;
/*
(remoterel->replident == REPLICA_IDENTITY_FULL));
if (OidIsValid(localidxoid))
+ {
+#ifdef USE_ASSERT_CHECKING
+ Relation idxrel = index_open(localidxoid, AccessShareLock);
+
+ /* Index must be PK, RI, or usable for REPLICA IDENTITY FULL tables */
+ Assert(GetRelationIdentityOrPK(idxrel) == localidxoid ||
+ IsIndexUsableForReplicaIdentityFull(BuildIndexInfo(idxrel),
+ edata->targetRel->attrmap));
+ index_close(idxrel, AccessShareLock);
+#endif
+
found = RelationFindReplTupleByIndex(localrel, localidxoid,
LockTupleExclusive,
remoteslot, *localslot);
+ }
else
found = RelationFindReplTupleSeq(localrel, LockTupleExclusive,
remoteslot, *localslot);
bool found;
/* Get the matching local tuple from the partition. */
- found = FindReplTupleInLocalRel(estate, partrel,
+ found = FindReplTupleInLocalRel(edata, partrel,
&part_entry->remoterel,
part_entry->localindexoid,
remoteslot_part, &localslot);
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