Use multi-inserts for pg_attribute and pg_shdepend

For pg_attribute, this allows to insert at once a full set of attributes
for a relation (roughly 15% of WAL reduction in extreme cases).  For
pg_shdepend, this reduces the work done when creating new shared
dependencies from a database template.  The number of slots used for the
insertion is capped at 64kB of data inserted for both, depending on the
number of items to insert and the length of the rows involved.

More can be done for other catalogs, like pg_depend.  This part requires
a different approach as the number of slots to use depends also on the
number of entries discarded as pinned dependencies.  This is also
related to the rework or dependency handling for ALTER TABLE and CREATE
TABLE, mainly.

Author: Daniel Gustafsson
Reviewed-by: Andres Freund, Michael Paquier
Discussion: https://postgr.es/m/20190213182737.mxn6hkdxwrzgxk35@alap3.anarazel.de

Author: michaelpq

src/backend/access/heap/heapam.c

@@ -2164,8 +2164,8 @@ heap_multi_insert(Relation relation, TupleTableSlot **slots, int ntuples,
 		RelationPutHeapTuple(relation, buffer, heaptuples[ndone], false);
 
 		/*
-		 * Note that heap_multi_insert is not used for catalog tuples yet, but
-		 * this will cover the gap once that is the case.
+		 * For logical decoding we need combocids to properly decode the
+		 * catalog.
 		 */
 		if (needwal && need_cids)
 			log_heap_new_cid(relation, heaptuples[ndone]);
@@ -2180,8 +2180,8 @@ heap_multi_insert(Relation relation, TupleTableSlot **slots, int ntuples,
 			RelationPutHeapTuple(relation, buffer, heaptup, false);
 
 			/*
-			 * We don't use heap_multi_insert for catalog tuples yet, but
-			 * better be prepared...
+			 * For logical decoding we need combocids to properly decode the
+			 * catalog.
 			 */
 			if (needwal && need_cids)
 				log_heap_new_cid(relation, heaptup);

src/backend/catalog/heap.c

@@ -710,70 +710,122 @@ CheckAttributeType(const char *attname,
 }
 
 /*
- * InsertPgAttributeTuple
- *		Construct and insert a new tuple in pg_attribute.
+ * Cap the maximum amount of bytes allocated for InsertPgAttributeTuples()
+ * slots.
+ */
+#define MAX_PGATTRIBUTE_INSERT_BYTES 65535
+
+/*
+ * InsertPgAttributeTuples
+ *		Construct and insert a set of tuples in pg_attribute.
  *
- * Caller has already opened and locked pg_attribute.  new_attribute is the
- * attribute to insert.  attcacheoff is always initialized to -1, attacl,
- * attfdwoptions and attmissingval are always initialized to NULL.
+ * Caller has already opened and locked pg_attribute.  tupdesc contains the
+ * attributes to insert.  attcacheoff is always initialized to -1, attacl,
+ * attfdwoptions and attmissingval are always initialized to NULL.  attoptions
+ * must contain the same number of elements as tupdesc, or be NULL.
  *
  * indstate is the index state for CatalogTupleInsertWithInfo.  It can be
  * passed as NULL, in which case we'll fetch the necessary info.  (Don't do
  * this when inserting multiple attributes, because it's a tad more
  * expensive.)
+ *
+ * new_rel_oid is the relation OID assigned to the attributes inserted.
+ * If set to InvalidOid, the relation OID from tupdesc is used instead.
  */
 void
-InsertPgAttributeTuple(Relation pg_attribute_rel,
-					   Form_pg_attribute new_attribute,
-					   Datum attoptions,
-					   CatalogIndexState indstate)
+InsertPgAttributeTuples(Relation pg_attribute_rel,
+						TupleDesc tupdesc,
+						Oid new_rel_oid,
+						Datum *attoptions,
+						CatalogIndexState indstate)
 {
-	Datum		values[Natts_pg_attribute];
-	bool		nulls[Natts_pg_attribute];
-	HeapTuple	tup;
+	TupleTableSlot **slot;
+	TupleDesc	td;
+	int			nslots;
+	int			natts = 0;
+	int			slotCount = 0;
+	bool		close_index = false;
+
+	td = RelationGetDescr(pg_attribute_rel);
+
+	/* Initialize the number of slots to use */
+	nslots = Min(tupdesc->natts,
+				 (MAX_PGATTRIBUTE_INSERT_BYTES / sizeof(FormData_pg_attribute)));
+	slot = palloc(sizeof(TupleTableSlot *) * nslots);
+	for (int i = 0; i < nslots; i++)
+		slot[i] = MakeSingleTupleTableSlot(td, &TTSOpsHeapTuple);
+
+	while (natts < tupdesc->natts)
+	{
+		Form_pg_attribute attrs = TupleDescAttr(tupdesc, natts);
 
-	/* This is a tad tedious, but way cleaner than what we used to do... */
-	memset(values, 0, sizeof(values));
-	memset(nulls, false, sizeof(nulls));
+		ExecClearTuple(slot[slotCount]);
 
-	values[Anum_pg_attribute_attrelid - 1] = ObjectIdGetDatum(new_attribute->attrelid);
-	values[Anum_pg_attribute_attname - 1] = NameGetDatum(&new_attribute->attname);
-	values[Anum_pg_attribute_atttypid - 1] = ObjectIdGetDatum(new_attribute->atttypid);
-	values[Anum_pg_attribute_attstattarget - 1] = Int32GetDatum(new_attribute->attstattarget);
-	values[Anum_pg_attribute_attlen - 1] = Int16GetDatum(new_attribute->attlen);
-	values[Anum_pg_attribute_attnum - 1] = Int16GetDatum(new_attribute->attnum);
-	values[Anum_pg_attribute_attndims - 1] = Int32GetDatum(new_attribute->attndims);
-	values[Anum_pg_attribute_attcacheoff - 1] = Int32GetDatum(-1);
-	values[Anum_pg_attribute_atttypmod - 1] = Int32GetDatum(new_attribute->atttypmod);
-	values[Anum_pg_attribute_attbyval - 1] = BoolGetDatum(new_attribute->attbyval);
-	values[Anum_pg_attribute_attstorage - 1] = CharGetDatum(new_attribute->attstorage);
-	values[Anum_pg_attribute_attalign - 1] = CharGetDatum(new_attribute->attalign);
-	values[Anum_pg_attribute_attnotnull - 1] = BoolGetDatum(new_attribute->attnotnull);
-	values[Anum_pg_attribute_atthasdef - 1] = BoolGetDatum(new_attribute->atthasdef);
-	values[Anum_pg_attribute_atthasmissing - 1] = BoolGetDatum(new_attribute->atthasmissing);
-	values[Anum_pg_attribute_attidentity - 1] = CharGetDatum(new_attribute->attidentity);
-	values[Anum_pg_attribute_attgenerated - 1] = CharGetDatum(new_attribute->attgenerated);
-	values[Anum_pg_attribute_attisdropped - 1] = BoolGetDatum(new_attribute->attisdropped);
-	values[Anum_pg_attribute_attislocal - 1] = BoolGetDatum(new_attribute->attislocal);
-	values[Anum_pg_attribute_attinhcount - 1] = Int32GetDatum(new_attribute->attinhcount);
-	values[Anum_pg_attribute_attcollation - 1] = ObjectIdGetDatum(new_attribute->attcollation);
-	values[Anum_pg_attribute_attoptions - 1] = attoptions;
-
-	/* start out with empty permissions and empty options */
-	nulls[Anum_pg_attribute_attacl - 1] = true;
-	nulls[Anum_pg_attribute_attoptions - 1] = attoptions == (Datum) 0;
-	nulls[Anum_pg_attribute_attfdwoptions - 1] = true;
-	nulls[Anum_pg_attribute_attmissingval - 1] = true;
-
-	tup = heap_form_tuple(RelationGetDescr(pg_attribute_rel), values, nulls);
+		if (new_rel_oid != InvalidOid)
+			slot[slotCount]->tts_values[Anum_pg_attribute_attrelid - 1] = ObjectIdGetDatum(new_rel_oid);
+		else
+			slot[slotCount]->tts_values[Anum_pg_attribute_attrelid - 1] = ObjectIdGetDatum(attrs->attrelid);
+
+		slot[slotCount]->tts_values[Anum_pg_attribute_attname - 1] = NameGetDatum(&attrs->attname);
+		slot[slotCount]->tts_values[Anum_pg_attribute_atttypid - 1] = ObjectIdGetDatum(attrs->atttypid);
+		slot[slotCount]->tts_values[Anum_pg_attribute_attstattarget - 1] = Int32GetDatum(attrs->attstattarget);
+		slot[slotCount]->tts_values[Anum_pg_attribute_attlen - 1] = Int16GetDatum(attrs->attlen);
+		slot[slotCount]->tts_values[Anum_pg_attribute_attnum - 1] = Int16GetDatum(attrs->attnum);
+		slot[slotCount]->tts_values[Anum_pg_attribute_attndims - 1] = Int32GetDatum(attrs->attndims);
+		slot[slotCount]->tts_values[Anum_pg_attribute_attcacheoff - 1] = Int32GetDatum(-1);
+		slot[slotCount]->tts_values[Anum_pg_attribute_atttypmod - 1] = Int32GetDatum(attrs->atttypmod);
+		slot[slotCount]->tts_values[Anum_pg_attribute_attbyval - 1] = BoolGetDatum(attrs->attbyval);
+		slot[slotCount]->tts_values[Anum_pg_attribute_attstorage - 1] = CharGetDatum(attrs->attstorage);
+		slot[slotCount]->tts_values[Anum_pg_attribute_attalign - 1] = CharGetDatum(attrs->attalign);
+		slot[slotCount]->tts_values[Anum_pg_attribute_attnotnull - 1] = BoolGetDatum(attrs->attnotnull);
+		slot[slotCount]->tts_values[Anum_pg_attribute_atthasdef - 1] = BoolGetDatum(attrs->atthasdef);
+		slot[slotCount]->tts_values[Anum_pg_attribute_atthasmissing - 1] = BoolGetDatum(attrs->atthasmissing);
+		slot[slotCount]->tts_values[Anum_pg_attribute_attidentity - 1] = CharGetDatum(attrs->attidentity);
+		slot[slotCount]->tts_values[Anum_pg_attribute_attgenerated - 1] = CharGetDatum(attrs->attgenerated);
+		slot[slotCount]->tts_values[Anum_pg_attribute_attisdropped - 1] = BoolGetDatum(attrs->attisdropped);
+		slot[slotCount]->tts_values[Anum_pg_attribute_attislocal - 1] = BoolGetDatum(attrs->attislocal);
+		slot[slotCount]->tts_values[Anum_pg_attribute_attinhcount - 1] = Int32GetDatum(attrs->attinhcount);
+		slot[slotCount]->tts_values[Anum_pg_attribute_attcollation - 1] = ObjectIdGetDatum(attrs->attcollation);
+		if (attoptions && attoptions[natts] != (Datum) 0)
+			slot[slotCount]->tts_values[Anum_pg_attribute_attoptions - 1] = attoptions[natts];
+		else
+			slot[slotCount]->tts_isnull[Anum_pg_attribute_attoptions - 1] = true;
 
-	/* finally insert the new tuple, update the indexes, and clean up */
-	if (indstate != NULL)
-		CatalogTupleInsertWithInfo(pg_attribute_rel, tup, indstate);
-	else
-		CatalogTupleInsert(pg_attribute_rel, tup);
+		/* start out with empty permissions and empty options */
+		slot[slotCount]->tts_isnull[Anum_pg_attribute_attacl - 1] = true;
+		slot[slotCount]->tts_isnull[Anum_pg_attribute_attfdwoptions - 1] = true;
+		slot[slotCount]->tts_isnull[Anum_pg_attribute_attmissingval - 1] = true;
 
-	heap_freetuple(tup);
+		ExecStoreVirtualTuple(slot[slotCount]);
+		slotCount++;
+
+		/*
+		 * If slots are full or the end of processing has been reached, insert
+		 * a batch of tuples.
+		 */
+		if (slotCount == nslots || natts == tupdesc->natts - 1)
+		{
+			/* fetch index info only when we know we need it */
+			if (!indstate)
+			{
+				indstate = CatalogOpenIndexes(pg_attribute_rel);
+				close_index = true;
+			}
+
+			/* insert the new tuples and update the indexes */
+			CatalogTuplesMultiInsertWithInfo(pg_attribute_rel, slot, slotCount,
+											 indstate);
+			slotCount = 0;
+		}
+
+		natts++;
+	}
+
+	if (close_index)
+		CatalogCloseIndexes(indstate);
+	for (int i = 0; i < nslots; i++)
+		ExecDropSingleTupleTableSlot(slot[i]);
+	pfree(slot);
 }
 
 /* --------------------------------
@@ -788,8 +840,6 @@ AddNewAttributeTuples(Oid new_rel_oid,
 					  TupleDesc tupdesc,
 					  char relkind)
 {
-	Form_pg_attribute attr;
-	int			i;
 	Relation	rel;
 	CatalogIndexState indstate;
 	int			natts = tupdesc->natts;
@@ -803,30 +853,26 @@ AddNewAttributeTuples(Oid new_rel_oid,
 
 	indstate = CatalogOpenIndexes(rel);
 
-	/*
-	 * First we add the user attributes.  This is also a convenient place to
-	 * add dependencies on their datatypes and collations.
-	 */
-	for (i = 0; i < natts; i++)
-	{
-		attr = TupleDescAttr(tupdesc, i);
-		/* Fill in the correct relation OID */
-		attr->attrelid = new_rel_oid;
-		/* Make sure this is OK, too */
-		attr->attstattarget = -1;
-
-		InsertPgAttributeTuple(rel, attr, (Datum) 0, indstate);
+	/* set stats detail level to a sane default */
+	for (int i = 0; i < natts; i++)
+		tupdesc->attrs[i].attstattarget = -1;
+	InsertPgAttributeTuples(rel, tupdesc, new_rel_oid, NULL, indstate);
 
+	/* add dependencies on their datatypes and collations */
+	for (int i = 0; i < natts; i++)
+	{
 		/* Add dependency info */
 		ObjectAddressSubSet(myself, RelationRelationId, new_rel_oid, i + 1);
-		ObjectAddressSet(referenced, TypeRelationId, attr->atttypid);
+		ObjectAddressSet(referenced, TypeRelationId,
+						 tupdesc->attrs[i].atttypid);
 		recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
 
 		/* The default collation is pinned, so don't bother recording it */
-		if (OidIsValid(attr->attcollation) &&
-			attr->attcollation != DEFAULT_COLLATION_OID)
+		if (OidIsValid(tupdesc->attrs[i].attcollation) &&
+			tupdesc->attrs[i].attcollation != DEFAULT_COLLATION_OID)
 		{
-			ObjectAddressSet(referenced, CollationRelationId, attr->attcollation);
+			ObjectAddressSet(referenced, CollationRelationId,
+							 tupdesc->attrs[i].attcollation);
 			recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
 		}
 	}
@@ -838,17 +884,12 @@ AddNewAttributeTuples(Oid new_rel_oid,
 	 */
 	if (relkind != RELKIND_VIEW && relkind != RELKIND_COMPOSITE_TYPE)
 	{
-		for (i = 0; i < (int) lengthof(SysAtt); i++)
-		{
-			FormData_pg_attribute attStruct;
+		TupleDesc	td;
 
-			memcpy(&attStruct, SysAtt[i], sizeof(FormData_pg_attribute));
+		td = CreateTupleDesc(lengthof(SysAtt), (FormData_pg_attribute **) &SysAtt);
 
-			/* Fill in the correct relation OID in the copied tuple */
-			attStruct.attrelid = new_rel_oid;
-
-			InsertPgAttributeTuple(rel, &attStruct, (Datum) 0, indstate);
-		}
+		InsertPgAttributeTuples(rel, td, new_rel_oid, NULL, indstate);
+		FreeTupleDesc(td);
 	}
 
 	/*

src/backend/catalog/index.c

@@ -106,8 +106,7 @@ static TupleDesc ConstructTupleDescriptor(Relation heapRelation,
 										  Oid *classObjectId);
 static void InitializeAttributeOids(Relation indexRelation,
 									int numatts, Oid indexoid);
-static void AppendAttributeTuples(Relation indexRelation, int numatts,
-								  Datum *attopts);
+static void AppendAttributeTuples(Relation indexRelation, Datum *attopts);
 static void UpdateIndexRelation(Oid indexoid, Oid heapoid,
 								Oid parentIndexId,
 								IndexInfo *indexInfo,
@@ -485,12 +484,11 @@ InitializeAttributeOids(Relation indexRelation,
  * ----------------------------------------------------------------
  */
 static void
-AppendAttributeTuples(Relation indexRelation, int numatts, Datum *attopts)
+AppendAttributeTuples(Relation indexRelation, Datum *attopts)
 {
 	Relation	pg_attribute;
 	CatalogIndexState indstate;
 	TupleDesc	indexTupDesc;
-	int			i;
 
 	/*
 	 * open the attribute relation and its indexes
@@ -504,15 +502,7 @@ AppendAttributeTuples(Relation indexRelation, int numatts, Datum *attopts)
 	 */
 	indexTupDesc = RelationGetDescr(indexRelation);
 
-	for (i = 0; i < numatts; i++)
-	{
-		Form_pg_attribute attr = TupleDescAttr(indexTupDesc, i);
-		Datum		attoptions = attopts ? attopts[i] : (Datum) 0;
-
-		Assert(attr->attnum == i + 1);
-
-		InsertPgAttributeTuple(pg_attribute, attr, attoptions, indstate);
-	}
+	InsertPgAttributeTuples(pg_attribute, indexTupDesc, InvalidOid, attopts, indstate);
 
 	CatalogCloseIndexes(indstate);
 
@@ -979,8 +969,7 @@ index_create(Relation heapRelation,
 	/*
 	 * append ATTRIBUTE tuples for the index
 	 */
-	AppendAttributeTuples(indexRelation, indexInfo->ii_NumIndexAttrs,
-						  indexInfo->ii_OpclassOptions);
+	AppendAttributeTuples(indexRelation, indexInfo->ii_OpclassOptions);
 
 	/* ----------------
 	 *	  update pg_index

src/backend/catalog/indexing.c

@@ -18,6 +18,7 @@
 #include "access/genam.h"
 #include "access/heapam.h"
 #include "access/htup_details.h"
+#include "access/xact.h"
 #include "catalog/index.h"
 #include "catalog/indexing.h"
 #include "executor/executor.h"
@@ -250,6 +251,41 @@ CatalogTupleInsertWithInfo(Relation heapRel, HeapTuple tup,
 	CatalogIndexInsert(indstate, tup);
 }
 
+/*
+ * CatalogTuplesMultiInsertWithInfo - as above, but for multiple tuples
+ *
+ * Insert multiple tuples into the given catalog relation at once, with an
+ * amortized cost of CatalogOpenIndexes.
+ */
+void
+CatalogTuplesMultiInsertWithInfo(Relation heapRel, TupleTableSlot **slot,
+								 int ntuples, CatalogIndexState indstate)
+{
+	/* Nothing to do */
+	if (ntuples <= 0)
+		return;
+
+	heap_multi_insert(heapRel, slot, ntuples,
+					  GetCurrentCommandId(true), 0, NULL);
+
+	/*
+	 * There is no equivalent to heap_multi_insert for the catalog indexes, so
+	 * we must loop over and insert individually.
+	 */
+	for (int i = 0; i < ntuples; i++)
+	{
+		bool		should_free;
+		HeapTuple	tuple;
+
+		tuple = ExecFetchSlotHeapTuple(slot[i], true, &should_free);
+		tuple->t_tableOid = slot[i]->tts_tableOid;
+		CatalogIndexInsert(indstate, tuple);
+
+		if (should_free)
+			heap_freetuple(tuple);
+	}
+}
+
 /*
  * CatalogTupleUpdate - do heap and indexing work for updating a catalog tuple
  *