Subject: [PATCH v27 6/9] Add Incremental View Maintenance support

From: Yugo Nagata <[email-masked]>
Date: Thu, 21 Apr 2022 11:58:53 +0900

In this implementation, AFTER triggers are used to collect
tuplestores containing transition table contents. When multiple tables
are changed, multiple AFTER triggers are invoked, then the final AFTER
trigger performs actual update of the matview. In addition, BEFORE
triggers are also used to handle global information for view
maintenance. To calculate view deltas, we need both pre-state and
post-state of base tables. Post-update states are available in AFTER
trigger, and pre-update states can be calculated by filtering inserted
tuples using cmin/xmin system columns, and append deleted tuples which
are contained in an old transition table.

This patch also allows self-join, simultaneous updates of more than
one base table, and multiple updates of the same base table.

Incrementally Maintainable Materialized Views (IMMV) can contain
duplicated tuples. Also, DISTINCT clause is supported. When IMMV is
created with DISTINCT, multiplicity of tuples is counted and stored
in  "__ivm_count__" column, which is a hidden column of IMMV.
The value in __ivm_count__ is updated when IMMV is maintained
incrementally. A tuple in IMMV can be removed if and only if the
count becomes zero.
---
 src/backend/access/transam/xact.c   |    5 +
 src/backend/commands/createas.c     |  751 +++++++++++++
 src/backend/commands/indexcmds.c    |   40 +
 src/backend/commands/matview.c      | 1577 ++++++++++++++++++++++++++-
 src/backend/commands/tablecmds.c    |    9 +
 src/backend/nodes/copyfuncs.c       |    1 +
 src/backend/nodes/equalfuncs.c      |    1 +
 src/backend/nodes/outfuncs.c        |    1 +
 src/backend/nodes/readfuncs.c       |    1 +
 src/backend/parser/parse_relation.c |   18 +-
 src/backend/rewrite/rewriteDefine.c |    3 +-
 src/include/catalog/pg_proc.dat     |    8 +
 src/include/commands/createas.h     |    6 +
 src/include/commands/matview.h      |    8 +
 src/include/nodes/parsenodes.h      |    2 +
 15 files changed, 2391 insertions(+), 40 deletions(-)

diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index 53f3e7fd1a..0377f5a88b 100644
--- a/src/backend/access/transam/xact.c
+++ b/src/backend/access/transam/xact.c
@@ -36,6 +36,7 @@
 #include "catalog/pg_enum.h"
 #include "catalog/storage.h"
 #include "commands/async.h"
+#include "commands/matview.h"
 #include "commands/tablecmds.h"
 #include "commands/trigger.h"
 #include "common/pg_prng.h"
@@ -2792,6 +2793,7 @@ AbortTransaction(void)
 	AtAbort_Notify();
 	AtEOXact_RelationMap(false, is_parallel_worker);
 	AtAbort_Twophase();
+	AtAbort_IVM();
 
 	/*
 	 * Advertise the fact that we aborted in pg_xact (assuming that we got as
@@ -5032,6 +5034,9 @@ AbortSubTransaction(void)
 	AbortBufferIO();
 	UnlockBuffers();
 
+	/* Clean up hash entries for incremental view maintenance */
+	AtAbort_IVM();
+
 	/* Reset WAL record construction state */
 	XLogResetInsertion();
 
diff --git a/src/backend/commands/createas.c b/src/backend/commands/createas.c
index 9abbb6b555..1224a3b075 100644
--- a/src/backend/commands/createas.c
+++ b/src/backend/commands/createas.c
@@ -32,24 +32,41 @@
 #include "access/xact.h"
 #include "access/xlog.h"
 #include "catalog/namespace.h"
+#include "catalog/index.h"
+#include "catalog/pg_constraint.h"
+#include "catalog/pg_inherits.h"
+#include "catalog/pg_trigger.h"
+#include "catalog/pg_type.h"
 #include "catalog/toasting.h"
 #include "commands/createas.h"
+#include "commands/defrem.h"
 #include "commands/matview.h"
 #include "commands/prepare.h"
 #include "commands/tablecmds.h"
+#include "commands/tablespace.h"
+#include "commands/trigger.h"
 #include "commands/view.h"
 #include "miscadmin.h"
+#include "optimizer/clauses.h"
+#include "optimizer/optimizer.h"
 #include "nodes/makefuncs.h"
 #include "nodes/nodeFuncs.h"
+#include "parser/parser.h"
+#include "parser/parsetree.h"
 #include "parser/parse_clause.h"
+#include "parser/parse_func.h"
+#include "parser/parse_type.h"
 #include "rewrite/rewriteHandler.h"
+#include "rewrite/rewriteManip.h"
 #include "storage/smgr.h"
 #include "tcop/tcopprot.h"
 #include "utils/builtins.h"
+#include "utils/fmgroids.h"
 #include "utils/lsyscache.h"
 #include "utils/rel.h"
 #include "utils/rls.h"
 #include "utils/snapmgr.h"
+#include "utils/syscache.h"
 
 typedef struct
 {
@@ -73,6 +90,13 @@ static bool intorel_receive(TupleTableSlot *slot, DestReceiver *self);
 static void intorel_shutdown(DestReceiver *self);
 static void intorel_destroy(DestReceiver *self);
 
+static void CreateIvmTriggersOnBaseTablesRecurse(Query *qry, Node *node, Oid matviewOid,
+									 Relids *relids, bool ex_lock);
+static void CreateIvmTrigger(Oid relOid, Oid viewOid, int16 type, int16 timing, bool ex_lock);
+static void check_ivm_restriction(Node *node);
+static bool check_ivm_restriction_walker(Node *node, void *context);
+static Bitmapset *get_primary_key_attnos_from_query(Query *qry, List **constraintList, bool is_create);
+static Bitmapset *get_primary_key_attnos_from_query(Query *query, List **constraintList, bool is_create);
 
 /*
  * create_ctas_internal
@@ -108,6 +132,8 @@ create_ctas_internal(List *attrList, IntoClause *into)
 	create->oncommit = into->onCommit;
 	create->tablespacename = into->tableSpaceName;
 	create->if_not_exists = false;
+	/* Using Materialized view only */
+	create->ivm = into->ivm;
 	create->accessMethod = into->accessMethod;
 
 	/*
@@ -282,6 +308,21 @@ ExecCreateTableAs(ParseState *pstate, CreateTableAsStmt *stmt,
 		save_nestlevel = NewGUCNestLevel();
 	}
 
+	if (is_matview && into->ivm)
+	{
+		/* check if the query is supported in IMMV definition */
+		if (contain_mutable_functions((Node *) query))
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("mutable function is not supported on incrementally maintainable materialized view"),
+					 errhint("functions must be marked IMMUTABLE")));
+
+		check_ivm_restriction((Node *) query);
+
+		/* For IMMV, we need to rewrite matview query */
+		query = rewriteQueryForIMMV(query, into->colNames);
+	}
+
 	if (into->skipData)
 	{
 		/*
@@ -358,11 +399,74 @@ ExecCreateTableAs(ParseState *pstate, CreateTableAsStmt *stmt,
 
 		/* Restore userid and security context */
 		SetUserIdAndSecContext(save_userid, save_sec_context);
+
+		if (into->ivm)
+		{
+			Oid matviewOid = address.objectId;
+			Relation matviewRel = table_open(matviewOid, NoLock);
+
+			/*
+			 * Mark relisivm field, if it's a matview and into->ivm is true.
+			 */
+			SetMatViewIVMState(matviewRel, true);
+
+			if (!into->skipData)
+			{
+				/* Create an index on incremental maintainable materialized view, if possible */
+				CreateIndexOnIMMV((Query *) into->viewQuery, matviewRel, true);
+
+				/* Create triggers on incremental maintainable materialized view */
+				CreateIvmTriggersOnBaseTables((Query *) into->viewQuery, matviewOid, true);
+			}
+			table_close(matviewRel, NoLock);
+		}
 	}
 
 	return address;
 }
 
+/*
+ * rewriteQueryForIMMV -- rewrite view definition query for IMMV
+ *
+ * count(*) is added for counting distinct tuples in views.
+ */
+Query *
+rewriteQueryForIMMV(Query *query, List *colNames)
+{
+	Query *rewritten;
+
+	TargetEntry *tle;
+	Node *node;
+	ParseState *pstate = make_parsestate(NULL);
+	FuncCall *fn;
+
+	rewritten = copyObject(query);
+	pstate->p_expr_kind = EXPR_KIND_SELECT_TARGET;
+
+	/*
+	 * Convert DISTINCT to GROUP BY and add count(*) for counting distinct
+	 * tuples in views.
+	 */
+	if (rewritten->distinctClause)
+	{
+		rewritten->groupClause = transformDistinctClause(NULL, &rewritten->targetList, rewritten->sortClause, false);
+
+		fn = makeFuncCall(list_make1(makeString("count")), NIL, COERCE_EXPLICIT_CALL, -1);
+		fn->agg_star = true;
+
+		node = ParseFuncOrColumn(pstate, fn->funcname, NIL, NULL, fn, false, -1);
+
+		tle = makeTargetEntry((Expr *) node,
+								list_length(rewritten->targetList) + 1,
+								pstrdup("__ivm_count__"),
+								false);
+		rewritten->targetList = lappend(rewritten->targetList, tle);
+		rewritten->hasAggs = true;
+	}
+
+	return rewritten;
+}
+
 /*
  * GetIntoRelEFlags --- compute executor flags needed for CREATE TABLE AS
  *
@@ -623,3 +727,650 @@ intorel_destroy(DestReceiver *self)
 {
 	pfree(self);
 }
+
+/*
+ * CreateIvmTriggersOnBaseTables -- create IVM triggers on all base tables
+ */
+void
+CreateIvmTriggersOnBaseTables(Query *qry, Oid matviewOid, bool is_create)
+{
+	Relids	relids = NULL;
+	bool	ex_lock = false;
+	Index	first_rtindex = is_create ? 1 : PRS2_NEW_VARNO + 1;
+	RangeTblEntry *rte;
+
+	/* Immediately return if we don't have any base tables. */
+	if (list_length(qry->rtable) < first_rtindex)
+		return;
+
+	/*
+	 * If the view has more than one base tables, we need an exclusive lock
+	 * on the view so that the view would be maintained serially to avoid
+	 * the inconsistency that occurs when two base tables are modified in
+	 * concurrent transactions. However, if the view has only one table,
+	 * we can use a weaker lock.
+	 *
+	 * The type of lock should be determined here, because if we check the
+	 * view definition at maintenance time, we need to acquire a weaker lock,
+	 * and upgrading the lock level after this increases probability of
+	 * deadlock.
+	 */
+
+	rte = list_nth(qry->rtable, first_rtindex - 1);
+	if (list_length(qry->rtable) > first_rtindex ||
+		rte->rtekind != RTE_RELATION)
+		ex_lock = true;
+
+	CreateIvmTriggersOnBaseTablesRecurse(qry, (Node *)qry, matviewOid, &relids, ex_lock);
+
+	bms_free(relids);
+}
+
+static void
+CreateIvmTriggersOnBaseTablesRecurse(Query *qry, Node *node, Oid matviewOid,
+									 Relids *relids, bool ex_lock)
+{
+	if (node == NULL)
+		return;
+
+	/* This can recurse, so check for excessive recursion */
+	check_stack_depth();
+
+	switch (nodeTag(node))
+	{
+		case T_Query:
+			{
+				Query *query = (Query *) node;
+
+				CreateIvmTriggersOnBaseTablesRecurse(qry, (Node *)query->jointree, matviewOid, relids, ex_lock);
+			}
+			break;
+
+		case T_RangeTblRef:
+			{
+				int			rti = ((RangeTblRef *) node)->rtindex;
+				RangeTblEntry *rte = rt_fetch(rti, qry->rtable);
+
+				if (rte->rtekind == RTE_RELATION && !bms_is_member(rte->relid, *relids))
+				{
+					CreateIvmTrigger(rte->relid, matviewOid, TRIGGER_TYPE_INSERT, TRIGGER_TYPE_BEFORE, ex_lock);
+					CreateIvmTrigger(rte->relid, matviewOid, TRIGGER_TYPE_DELETE, TRIGGER_TYPE_BEFORE, ex_lock);
+					CreateIvmTrigger(rte->relid, matviewOid, TRIGGER_TYPE_UPDATE, TRIGGER_TYPE_BEFORE, ex_lock);
+					CreateIvmTrigger(rte->relid, matviewOid, TRIGGER_TYPE_INSERT, TRIGGER_TYPE_AFTER, ex_lock);
+					CreateIvmTrigger(rte->relid, matviewOid, TRIGGER_TYPE_DELETE, TRIGGER_TYPE_AFTER, ex_lock);
+					CreateIvmTrigger(rte->relid, matviewOid, TRIGGER_TYPE_UPDATE, TRIGGER_TYPE_AFTER, ex_lock);
+
+					*relids = bms_add_member(*relids, rte->relid);
+				}
+			}
+			break;
+
+		case T_FromExpr:
+			{
+				FromExpr   *f = (FromExpr *) node;
+				ListCell   *l;
+
+				foreach(l, f->fromlist)
+					CreateIvmTriggersOnBaseTablesRecurse(qry, lfirst(l), matviewOid, relids, ex_lock);
+			}
+			break;
+
+		case T_JoinExpr:
+			{
+				JoinExpr   *j = (JoinExpr *) node;
+
+				CreateIvmTriggersOnBaseTablesRecurse(qry, j->larg, matviewOid, relids, ex_lock);
+				CreateIvmTriggersOnBaseTablesRecurse(qry, j->rarg, matviewOid, relids, ex_lock);
+			}
+			break;
+
+		default:
+			elog(ERROR, "unrecognized node type: %d", (int) nodeTag(node));
+	}
+}
+
+/*
+ * CreateIvmTrigger -- create IVM trigger on a base table
+ */
+static void
+CreateIvmTrigger(Oid relOid, Oid viewOid, int16 type, int16 timing, bool ex_lock)
+{
+	ObjectAddress	refaddr;
+	ObjectAddress	address;
+	CreateTrigStmt *ivm_trigger;
+	List *transitionRels = NIL;
+
+	Assert(timing == TRIGGER_TYPE_BEFORE || timing == TRIGGER_TYPE_AFTER);
+
+	refaddr.classId = RelationRelationId;
+	refaddr.objectId = viewOid;
+	refaddr.objectSubId = 0;
+
+	ivm_trigger = makeNode(CreateTrigStmt);
+	ivm_trigger->relation = NULL;
+	ivm_trigger->row = false;
+
+	ivm_trigger->timing = timing;
+	ivm_trigger->events = type;
+
+	switch (type)
+	{
+		case TRIGGER_TYPE_INSERT:
+			ivm_trigger->trigname = (timing == TRIGGER_TYPE_BEFORE ? "IVM_trigger_ins_before" : "IVM_trigger_ins_after");
+			break;
+		case TRIGGER_TYPE_DELETE:
+			ivm_trigger->trigname = (timing == TRIGGER_TYPE_BEFORE ? "IVM_trigger_del_before" : "IVM_trigger_del_after");
+			break;
+		case TRIGGER_TYPE_UPDATE:
+			ivm_trigger->trigname = (timing == TRIGGER_TYPE_BEFORE ? "IVM_trigger_upd_before" : "IVM_trigger_upd_after");
+			break;
+		default:
+			elog(ERROR, "unsupported trigger type");
+	}
+
+	if (timing == TRIGGER_TYPE_AFTER)
+	{
+		if (type == TRIGGER_TYPE_INSERT || type == TRIGGER_TYPE_UPDATE)
+		{
+			TriggerTransition *n = makeNode(TriggerTransition);
+			n->name = "__ivm_newtable";
+			n->isNew = true;
+			n->isTable = true;
+
+			transitionRels = lappend(transitionRels, n);
+		}
+		if (type == TRIGGER_TYPE_DELETE || type == TRIGGER_TYPE_UPDATE)
+		{
+			TriggerTransition *n = makeNode(TriggerTransition);
+			n->name = "__ivm_oldtable";
+			n->isNew = false;
+			n->isTable = true;
+
+			transitionRels = lappend(transitionRels, n);
+		}
+	}
+
+	ivm_trigger->funcname =
+		(timing == TRIGGER_TYPE_BEFORE ? SystemFuncName("IVM_immediate_before") : SystemFuncName("IVM_immediate_maintenance"));
+
+	ivm_trigger->columns = NIL;
+	ivm_trigger->transitionRels = transitionRels;
+	ivm_trigger->whenClause = NULL;
+	ivm_trigger->isconstraint = false;
+	ivm_trigger->deferrable = false;
+	ivm_trigger->initdeferred = false;
+	ivm_trigger->constrrel = NULL;
+	ivm_trigger->args = list_make2(
+		makeString(DatumGetPointer(DirectFunctionCall1(oidout, ObjectIdGetDatum(viewOid)))),
+		makeString(DatumGetPointer(DirectFunctionCall1(boolout, BoolGetDatum(ex_lock))))
+		);
+
+	address = CreateTrigger(ivm_trigger, NULL, relOid, InvalidOid, InvalidOid,
+						 InvalidOid, InvalidOid, InvalidOid, NULL, true, false);
+
+	recordDependencyOn(&address, &refaddr, DEPENDENCY_AUTO);
+
+	/* Make changes-so-far visible */
+	CommandCounterIncrement();
+}
+
+/*
+ * check_ivm_restriction --- look for specify nodes in the query tree
+ */
+static void
+check_ivm_restriction(Node *node)
+{
+	check_ivm_restriction_walker(node, NULL);
+}
+
+static bool
+check_ivm_restriction_walker(Node *node, void *context)
+{
+	if (node == NULL)
+		return false;
+
+	/*
+	 * We currently don't support Sub-Query.
+	 */
+	if (IsA(node, SubPlan) || IsA(node, SubLink))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("subquery is not supported on incrementally maintainable materialized view")));
+
+	/* This can recurse, so check for excessive recursion */
+	check_stack_depth();
+
+	switch (nodeTag(node))
+	{
+		case T_Query:
+			{
+				Query *qry = (Query *)node;
+				ListCell   *lc;
+				List       *vars;
+
+				/* if contained CTE, return error */
+				if (qry->cteList != NIL)
+					ereport(ERROR,
+							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+							 errmsg("CTE is not supported on incrementally maintainable materialized view")));
+				if (qry->havingQual != NULL)
+					ereport(ERROR,
+							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+							 errmsg(" HAVING clause is not supported on incrementally maintainable materialized view")));
+				if (qry->sortClause != NIL)	/* There is a possibility that we don't need to return an error */
+					ereport(ERROR,
+							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+							 errmsg("ORDER BY clause is not supported on incrementally maintainable materialized view")));
+				if (qry->limitOffset != NULL || qry->limitCount != NULL)
+					ereport(ERROR,
+							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+							 errmsg("LIMIT/OFFSET clause is not supported on incrementally maintainable materialized view")));
+				if (qry->hasDistinctOn)
+					ereport(ERROR,
+							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+							 errmsg("DISTINCT ON is not supported on incrementally maintainable materialized view")));
+				if (qry->hasWindowFuncs)
+					ereport(ERROR,
+							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+							 errmsg("window functions are not supported on incrementally maintainable materialized view")));
+				if (qry->groupingSets != NIL)
+					ereport(ERROR,
+							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+							 errmsg("GROUPING SETS, ROLLUP, or CUBE clauses is not supported on incrementally maintainable materialized view")));
+				if (qry->setOperations != NULL)
+					ereport(ERROR,
+							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+							 errmsg("UNION/INTERSECT/EXCEPT statements are not supported on incrementally maintainable materialized view")));
+				if (list_length(qry->targetList) == 0)
+					ereport(ERROR,
+							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+							 errmsg("empty target list is not supported on incrementally maintainable materialized view")));
+				if (qry->rowMarks != NIL)
+					ereport(ERROR,
+							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+							 errmsg("FOR UPDATE/SHARE clause is not supported on incrementally maintainable materialized view")));
+
+				/* system column restrictions */
+				vars = pull_vars_of_level((Node *) qry, 0);
+				foreach(lc, vars)
+				{
+					if (IsA(lfirst(lc), Var))
+					{
+						Var *var = (Var *) lfirst(lc);
+						/* if system column, return error */
+						if (var->varattno < 0)
+							ereport(ERROR,
+									(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+									 errmsg("system column is not supported on incrementally maintainable materialized view")));
+					}
+				}
+
+				/* restrictions for rtable */
+				foreach(lc, qry->rtable)
+				{
+					RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
+
+					if (rte->subquery)
+						ereport(ERROR,
+								(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+								 errmsg("subquery is not supported on incrementally maintainable materialized view")));
+
+					if (rte->tablesample != NULL)
+						ereport(ERROR,
+								(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+								 errmsg("TABLESAMPLE clause is not supported on incrementally maintainable materialized view")));
+
+					if (rte->relkind == RELKIND_PARTITIONED_TABLE)
+						ereport(ERROR,
+								(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+								 errmsg("partitioned table is not supported on incrementally maintainable materialized view")));
+
+					if (rte->relkind == RELKIND_RELATION && has_superclass(rte->relid))
+						ereport(ERROR,
+								(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+								 errmsg("partitions is not supported on incrementally maintainable materialized view")));
+
+					if (rte->relkind == RELKIND_RELATION && find_inheritance_children(rte->relid, NoLock) != NIL)
+						ereport(ERROR,
+								(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+								 errmsg("inheritance parent is not supported on incrementally maintainable materialized view")));
+
+					if (rte->relkind == RELKIND_FOREIGN_TABLE)
+						ereport(ERROR,
+								(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+								 errmsg("foreign table is not supported on incrementally maintainable materialized view")));
+
+					if (rte->relkind == RELKIND_VIEW ||
+						rte->relkind == RELKIND_MATVIEW)
+						ereport(ERROR,
+								(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+								 errmsg("VIEW or MATERIALIZED VIEW is not supported on incrementally maintainable materialized view")));
+
+					if (rte->rtekind == RTE_VALUES)
+						ereport(ERROR,
+								(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+								 errmsg("VALUES is not supported on incrementally maintainable materialized view")));
+
+				}
+
+				query_tree_walker(qry, check_ivm_restriction_walker, NULL, QTW_IGNORE_RANGE_TABLE);
+
+				break;
+			}
+		case T_TargetEntry:
+			{
+				TargetEntry *tle = (TargetEntry *)node;
+				if (isIvmName(tle->resname))
+						ereport(ERROR,
+								(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+								 errmsg("column name %s is not supported on incrementally maintainable materialized view", tle->resname)));
+
+				expression_tree_walker(node, check_ivm_restriction_walker, NULL);
+				break;
+			}
+		case T_JoinExpr:
+			{
+				JoinExpr *joinexpr = (JoinExpr *)node;
+
+				if (joinexpr->jointype > JOIN_INNER)
+						ereport(ERROR,
+								(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+								 errmsg("OUTER JOIN is not supported on incrementally maintainable materialized view")));
+
+				expression_tree_walker(node, check_ivm_restriction_walker, NULL);
+			}
+			break;
+		case T_Aggref:
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("aggregate function is not supported on incrementally maintainable materialized view")));
+			break;
+		default:
+			expression_tree_walker(node, check_ivm_restriction_walker, (void *) context);
+			break;
+	}
+	return false;
+}
+
+/*
+ * CreateIndexOnIMMV
+ *
+ * Create a unique index on incremental maintainable materialized view.
+ * If the view definition query has a GROUP BY clause, the index is created
+ * on the columns of GROUP BY expressions. Otherwise, if the view contains
+ * all primary key attritubes of its base tables in the target list, the index
+ * is created on these attritubes. In other cases, no index is created.
+ */
+void
+CreateIndexOnIMMV(Query *query, Relation matviewRel, bool is_create)
+{
+	ListCell *lc;
+	IndexStmt  *index;
+	ObjectAddress address;
+	List *constraintList = NIL;
+	char		idxname[NAMEDATALEN];
+	List	   *indexoidlist = RelationGetIndexList(matviewRel);
+	ListCell   *indexoidscan;
+
+	snprintf(idxname, sizeof(idxname), "%s_index", RelationGetRelationName(matviewRel));
+
+	index = makeNode(IndexStmt);
+
+	/*
+	 * We consider null values not distinct to make sure that views with DISTINCT
+	 * or GROUP BY don't contain multiple NULL rows when NULL is inserted to
+	 * a base table concurrently.
+	 */
+	index->nulls_not_distinct = true;
+
+	index->unique = true;
+	index->primary = false;
+	index->isconstraint = false;
+	index->deferrable = false;
+	index->initdeferred = false;
+	index->idxname = idxname;
+	index->relation =
+		makeRangeVar(get_namespace_name(RelationGetNamespace(matviewRel)),
+					 pstrdup(RelationGetRelationName(matviewRel)),
+					 -1);
+	index->accessMethod = DEFAULT_INDEX_TYPE;
+	index->options = NIL;
+	index->tableSpace = get_tablespace_name(matviewRel->rd_rel->reltablespace);
+	index->whereClause = NULL;
+	index->indexParams = NIL;
+	index->indexIncludingParams = NIL;
+	index->excludeOpNames = NIL;
+	index->idxcomment = NULL;
+	index->indexOid = InvalidOid;
+	index->oldNode = InvalidOid;
+	index->oldCreateSubid = InvalidSubTransactionId;
+	index->oldFirstRelfilenodeSubid = InvalidSubTransactionId;
+	index->transformed = true;
+	index->concurrent = false;
+	index->if_not_exists = false;
+
+	if (query->distinctClause)
+	{
+		/* create unique constraint on all columns */
+		foreach(lc, query->targetList)
+		{
+			TargetEntry *tle = (TargetEntry *) lfirst(lc);
+			Form_pg_attribute attr = TupleDescAttr(matviewRel->rd_att, tle->resno - 1);
+			IndexElem  *iparam;
+
+			iparam = makeNode(IndexElem);
+			iparam->name = pstrdup(NameStr(attr->attname));
+			iparam->expr = NULL;
+			iparam->indexcolname = NULL;
+			iparam->collation = NIL;
+			iparam->opclass = NIL;
+			iparam->opclassopts = NIL;
+			iparam->ordering = SORTBY_DEFAULT;
+			iparam->nulls_ordering = SORTBY_NULLS_DEFAULT;
+			index->indexParams = lappend(index->indexParams, iparam);
+		}
+	}
+	else
+	{
+		Bitmapset *key_attnos;
+
+		/* create index on the base tables' primary key columns */
+		key_attnos = get_primary_key_attnos_from_query(query, &constraintList, is_create);
+		if (key_attnos)
+		{
+			foreach(lc, query->targetList)
+			{
+				TargetEntry *tle = (TargetEntry *) lfirst(lc);
+				Form_pg_attribute attr = TupleDescAttr(matviewRel->rd_att, tle->resno - 1);
+
+				if (bms_is_member(tle->resno - FirstLowInvalidHeapAttributeNumber, key_attnos))
+				{
+					IndexElem  *iparam;
+
+					iparam = makeNode(IndexElem);
+					iparam->name = pstrdup(NameStr(attr->attname));
+					iparam->expr = NULL;
+					iparam->indexcolname = NULL;
+					iparam->collation = NIL;
+					iparam->opclass = NIL;
+					iparam->opclassopts = NIL;
+					iparam->ordering = SORTBY_DEFAULT;
+					iparam->nulls_ordering = SORTBY_NULLS_DEFAULT;
+					index->indexParams = lappend(index->indexParams, iparam);
+				}
+			}
+		}
+		else
+		{
+			/* create no index, just notice that an appropriate index is necessary for efficient IVM */
+			ereport(NOTICE,
+					(errmsg("could not create an index on materialized view \"%s\" automatically",
+							RelationGetRelationName(matviewRel)),
+					 errdetail("This target list does not have all the primary key columns, "
+							   "or this view does not contain DISTINCT clause."),
+					 errhint("Create an index on the materialized view for efficient incremental maintenance.")));
+			return;
+		}
+	}
+
+	/* If we have a compatible index, we don't need to create another. */
+	foreach(indexoidscan, indexoidlist)
+	{
+		Oid			indexoid = lfirst_oid(indexoidscan);
+		Relation	indexRel;
+		bool		hasCompatibleIndex = false;
+
+		indexRel = index_open(indexoid, AccessShareLock);
+
+		if (CheckIndexCompatible(indexRel->rd_id,
+								index->accessMethod,
+								index->indexParams,
+								index->excludeOpNames))
+			hasCompatibleIndex = true;
+
+		index_close(indexRel, AccessShareLock);
+
+		if (hasCompatibleIndex)
+			return;
+	}
+
+	address = DefineIndex(RelationGetRelid(matviewRel),
+						  index,
+						  InvalidOid,
+						  InvalidOid,
+						  InvalidOid,
+						  false, true, false, false, true);
+
+	ereport(NOTICE,
+			(errmsg("created index \"%s\" on materialized view \"%s\"",
+					idxname, RelationGetRelationName(matviewRel))));
+
+	/*
+	 * Make dependencies so that the index is dropped if any base tables's
+	 * primary key is dropped.
+	 */
+	foreach(lc, constraintList)
+	{
+		Oid constraintOid = lfirst_oid(lc);
+		ObjectAddress	refaddr;
+
+		refaddr.classId = ConstraintRelationId;
+		refaddr.objectId = constraintOid;
+		refaddr.objectSubId = 0;
+
+		recordDependencyOn(&address, &refaddr, DEPENDENCY_NORMAL);
+	}
+}
+
+
+/*
+ * get_primary_key_attnos_from_query
+ *
+ * Identify the columns in base tables' primary keys in the target list.
+ *
+ * Returns a Bitmapset of the column attnos of the primary key's columns of
+ * tables that used in the query.  The attnos are offset by
+ * FirstLowInvalidHeapAttributeNumber as same as get_primary_key_attnos.
+ *
+ * If any table has no primary key or any primary key's columns is not in
+ * the target list, return NULL.  We also return NULL if any pkey constraint
+ * is deferrable.
+ *
+ * constraintList is set to a list of the OIDs of the pkey constraints.
+ */
+static Bitmapset *
+get_primary_key_attnos_from_query(Query *query, List **constraintList, bool is_create)
+{
+	List *key_attnos_list = NIL;
+	ListCell *lc;
+	int i;
+	Bitmapset *keys = NULL;
+	Relids	rels_in_from;
+	PlannerInfo root;
+
+
+	/*
+	 * Collect primary key attributes from all tables used in query. The key attributes
+	 * sets for each table are stored in key_attnos_list in order by RTE index.
+	 */
+	i = 1;
+	foreach(lc, query->rtable)
+	{
+		RangeTblEntry *r = (RangeTblEntry*) lfirst(lc);
+		Bitmapset *key_attnos;
+		bool	has_pkey = true;
+		Index	first_rtindex = is_create ? 1 : PRS2_NEW_VARNO + 1;
+
+		/* skip NEW/OLD entries */
+		if (i >= first_rtindex)
+		{
+			/* for tables, call get_primary_key_attnos */
+			if (r->rtekind == RTE_RELATION)
+			{
+				Oid constraintOid;
+				key_attnos = get_primary_key_attnos(r->relid, false, &constraintOid);
+				*constraintList = lappend_oid(*constraintList, constraintOid);
+				has_pkey = (key_attnos != NULL);
+			}
+			/* for other RTEs, store NULL into key_attnos_list */
+			else
+				key_attnos = NULL;
+		}
+		else
+			key_attnos = NULL;
+
+		/*
+		 * If any table or subquery has no primary key or its pkey constraint is deferrable,
+		 * we cannot get key attributes for this query, so return NULL.
+		 */
+		if (!has_pkey)
+			return NULL;
+
+		key_attnos_list = lappend(key_attnos_list, key_attnos);
+		i++;
+	}
+
+	/* Collect key attributes appearing in the target list */
+	i = 1;
+	foreach(lc, query->targetList)
+	{
+		TargetEntry *tle = (TargetEntry *) flatten_join_alias_vars(query, lfirst(lc));
+
+		if (IsA(tle->expr, Var))
+		{
+			Var *var = (Var*) tle->expr;
+			Bitmapset *attnos = list_nth(key_attnos_list, var->varno - 1);
+
+			/* check if this attribute is from a base table's primary key */
+			if (bms_is_member(var->varattno - FirstLowInvalidHeapAttributeNumber, attnos))
+			{
+				/*
+				 * Remove found key attributes from key_attnos_list, and add this
+				 * to the result list.
+				 */
+				bms_del_member(attnos, var->varattno - FirstLowInvalidHeapAttributeNumber);
+				keys = bms_add_member(keys, i - FirstLowInvalidHeapAttributeNumber);
+			}
+		}
+		i++;
+	}
+
+	/* Collect relations appearing in the FROM clause */
+	rels_in_from = pull_varnos_of_level(&root, (Node *)query->jointree, 0);
+
+	/*
+	 * Check if all key attributes of relations in FROM are appearing in the target
+	 * list.  If an attribute remains in key_attnos_list in spite of the table is used
+	 * in FROM clause, the target is missing this key attribute, so we return NULL.
+	 */
+	i = 1;
+	foreach(lc, key_attnos_list)
+	{
+		Bitmapset *bms = (Bitmapset *)lfirst(lc);
+		if (!bms_is_empty(bms) && bms_is_member(i, rels_in_from))
+			return NULL;
+		i++;
+	}
+
+	return keys;
+}
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index cd30f15eba..a94b8ffd7d 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -36,6 +36,7 @@
 #include "commands/dbcommands.h"
 #include "commands/defrem.h"
 #include "commands/event_trigger.h"
+#include "commands/matview.h"
 #include "commands/progress.h"
 #include "commands/tablecmds.h"
 #include "commands/tablespace.h"
@@ -1055,6 +1056,45 @@ DefineIndex(Oid relationId,
 	safe_index = indexInfo->ii_Expressions == NIL &&
 		indexInfo->ii_Predicate == NIL;
 
+	/*
+	 * We disallow unique indexes on IVM columns of IMMVs.
+	 */
+	if (RelationIsIVM(rel) && stmt->unique)
+	{
+		for (i = 0; i < indexInfo->ii_NumIndexKeyAttrs; i++)
+		{
+			AttrNumber	attno = indexInfo->ii_IndexAttrNumbers[i];
+			if (attno > 0)
+			{
+				char *name = NameStr(TupleDescAttr(rel->rd_att, attno - 1)->attname);
+				if (name && isIvmName(name))
+					ereport(ERROR,
+							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+							 errmsg("unique index creation on IVM columns is not supported")));
+			}
+		}
+
+		if (indexInfo->ii_Expressions)
+		{
+			Bitmapset  *indexattrs = NULL;
+			int			varno = -1;
+
+			pull_varattnos((Node *) indexInfo->ii_Expressions, 1, &indexattrs);
+
+			while ((varno = bms_next_member(indexattrs, varno)) >= 0)
+			{
+				int attno = varno + FirstLowInvalidHeapAttributeNumber;
+				char *name = NameStr(TupleDescAttr(rel->rd_att, attno - 1)->attname);
+				if (name && isIvmName(name))
+					ereport(ERROR,
+							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+							 errmsg("unique index creation on IVM columns is not supported")));
+			}
+
+		}
+	}
+
+
 	/*
 	 * Report index creation if appropriate (delay this till after most of the
 	 * error checks)
diff --git a/src/backend/commands/matview.c b/src/backend/commands/matview.c
index 9ab248d25e..cb713328a0 100644
--- a/src/backend/commands/matview.c
+++ b/src/backend/commands/matview.c
@@ -25,26 +25,48 @@
 #include "catalog/indexing.h"
 #include "catalog/namespace.h"
 #include "catalog/pg_am.h"
+#include "catalog/pg_collation.h"
+#include "catalog/pg_depend.h"
+#include "catalog/pg_trigger.h"
+#include "catalog/pg_type.h"
 #include "catalog/pg_opclass.h"
 #include "catalog/pg_operator.h"
 #include "commands/cluster.h"
+#include "commands/defrem.h"
 #include "commands/matview.h"
 #include "commands/tablecmds.h"
 #include "commands/tablespace.h"
+#include "commands/createas.h"
 #include "executor/executor.h"
 #include "executor/spi.h"
+#include "executor/tstoreReceiver.h"
 #include "miscadmin.h"
+#include "nodes/makefuncs.h"
+#include "nodes/nodeFuncs.h"
+#include "optimizer/optimizer.h"
+#include "parser/analyze.h"
+#include "parser/parser.h"
+#include "parser/parsetree.h"
+#include "parser/parse_clause.h"
+#include "parser/parse_coerce.h"
+#include "parser/parse_collate.h"
+#include "parser/parse_func.h"
 #include "parser/parse_relation.h"
+#include "parser/parse_type.h"
 #include "pgstat.h"
 #include "rewrite/rewriteHandler.h"
+#include "rewrite/rewriteManip.h"
+#include "rewrite/rowsecurity.h"
 #include "storage/lmgr.h"
 #include "storage/smgr.h"
 #include "tcop/tcopprot.h"
 #include "utils/builtins.h"
+#include "utils/fmgroids.h"
 #include "utils/lsyscache.h"
 #include "utils/rel.h"
 #include "utils/snapmgr.h"
 #include "utils/syscache.h"
+#include "utils/typcache.h"

 typedef struct
@@ -58,6 +80,50 @@ typedef struct
 	BulkInsertState bistate;	/* bulk insert state */
 } DR_transientrel;
 
+#define MV_INIT_QUERYHASHSIZE	16
+
+/*
+ * MV_TriggerHashEntry
+ *
+ * Hash entry for base tables on which IVM trigger is invoked
+ */
+typedef struct MV_TriggerHashEntry
+{
+	Oid	matview_id;			/* OID of the materialized view */
+	int	before_trig_count;	/* count of before triggers invoked */
+	int	after_trig_count;	/* count of after triggers invoked */
+
+	TransactionId	xid;	/* Transaction id before the first table is modified*/
+	CommandId		cid;	/* Command id before the first table is modified */
+
+	List   *tables;		/* List of MV_TriggerTable */
+	bool	has_old;	/* tuples are deleted from any table? */
+	bool	has_new;	/* tuples are inserted into any table? */
+} MV_TriggerHashEntry;
+
+/*
+ * MV_TriggerTable
+ *
+ * IVM related data for tables on which the trigger is invoked.
+ */
+typedef struct MV_TriggerTable
+{
+	Oid		table_id;			/* OID of the modified table */
+	List   *old_tuplestores;	/* tuplestores for deleted tuples */
+	List   *new_tuplestores;	/* tuplestores for inserted tuples */
+	List   *old_rtes;			/* RTEs of ENRs for old_tuplestores*/
+	List   *new_rtes;			/* RTEs of ENRs for new_tuplestores */
+
+	List   *rte_indexes;		/* List of RTE index of the modified table */
+	RangeTblEntry *original_rte;	/* the original RTE saved before rewriting query */
+} MV_TriggerTable;
+
+static HTAB *mv_trigger_info = NULL;
+
+/* ENR name for materialized view delta */
+#define NEW_DELTA_ENRNAME "new_delta"
+#define OLD_DELTA_ENRNAME "old_delta"
+
 static int	matview_maintenance_depth = 0;
 
 static void transientrel_startup(DestReceiver *self, int operation, TupleDesc typeinfo);
@@ -65,7 +131,9 @@ static bool transientrel_receive(TupleTableSlot *slot, DestReceiver *self);
 static void transientrel_shutdown(DestReceiver *self);
 static void transientrel_destroy(DestReceiver *self);
 static uint64 refresh_matview_datafill(DestReceiver *dest, Query *query,
-									   const char *queryString);
+						 QueryEnvironment *queryEnv,
+						 TupleDesc *resultTupleDesc,
+						 const char *queryString);
 static char *make_temptable_name_n(char *tempname, int n);
 static void refresh_by_match_merge(Oid matviewOid, Oid tempOid, Oid relowner,
 								   int save_sec_context);
@@ -73,6 +141,45 @@ static void refresh_by_heap_swap(Oid matviewOid, Oid OIDNewHeap, char relpersist
 static bool is_usable_unique_index(Relation indexRel);
 static void OpenMatViewIncrementalMaintenance(void);
 static void CloseMatViewIncrementalMaintenance(void);
+static Query *get_matview_query(Relation matviewRel);
+
+static Query *rewrite_query_for_preupdate_state(Query *query, List *tables,
+								  TransactionId xid, CommandId cid,
+								  ParseState *pstate);
+static void register_delta_ENRs(ParseState *pstate, Query *query, List *tables);
+static char *make_delta_enr_name(const char *prefix, Oid relid, int count);
+static RangeTblEntry *get_prestate_rte(RangeTblEntry *rte, MV_TriggerTable *table,
+				 TransactionId xid, CommandId cid,
+				 QueryEnvironment *queryEnv);
+static RangeTblEntry *union_ENRs(RangeTblEntry *rte, Oid relid, List *enr_rtes, const char *prefix,
+		   QueryEnvironment *queryEnv);
+static Query *rewrite_query_for_distinct(Query *query, ParseState *pstate);
+
+static void calc_delta(MV_TriggerTable *table, int rte_index, Query *query,
+			DestReceiver *dest_old, DestReceiver *dest_new,
+			TupleDesc *tupdesc_old, TupleDesc *tupdesc_new,
+			QueryEnvironment *queryEnv);
+static Query *rewrite_query_for_postupdate_state(Query *query, MV_TriggerTable *table, int rte_index);
+
+static void apply_delta(Oid matviewOid, Tuplestorestate *old_tuplestores, Tuplestorestate *new_tuplestores,
+			TupleDesc tupdesc_old, TupleDesc tupdesc_new,
+			Query *query, bool use_count, char *count_colname);
+static void apply_old_delta(const char *matviewname, const char *deltaname_old,
+				List *keys);
+static void apply_old_delta_with_count(const char *matviewname, const char *deltaname_old,
+				List *keys, const char *count_colname);
+static void apply_new_delta(const char *matviewname, const char *deltaname_new,
+				StringInfo target_list);
+static void apply_new_delta_with_count(const char *matviewname, const char* deltaname_new,
+				List *keys, StringInfo target_list, const char* count_colname);
+static char *get_matching_condition_string(List *keys);
+static void generate_equal(StringInfo querybuf, Oid opttype,
+			   const char *leftop, const char *rightop);
+
+static void mv_InitHashTables(void);
+static void clean_up_IVM_hash_entry(MV_TriggerHashEntry *entry);
+
+static List *get_securityQuals(Oid relId, int rt_index, Query *query);
 
 /*
  * SetMatViewPopulatedState
@@ -114,6 +221,46 @@ SetMatViewPopulatedState(Relation relation, bool newstate)
 	CommandCounterIncrement();
 }
 
+/*
+ * SetMatViewIVMState
+ *		Mark a materialized view as IVM, or not.
+ *
+ * NOTE: caller must be holding an appropriate lock on the relation.
+ */
+void
+SetMatViewIVMState(Relation relation, bool newstate)
+{
+	Relation	pgrel;
+	HeapTuple	tuple;
+
+	Assert(relation->rd_rel->relkind == RELKIND_MATVIEW);
+
+	/*
+	 * Update relation's pg_class entry.  Crucial side-effect: other backends
+	 * (and this one too!) are sent SI message to make them rebuild relcache
+	 * entries.
+	 */
+	pgrel = table_open(RelationRelationId, RowExclusiveLock);
+	tuple = SearchSysCacheCopy1(RELOID,
+								ObjectIdGetDatum(RelationGetRelid(relation)));
+	if (!HeapTupleIsValid(tuple))
+		elog(ERROR, "cache lookup failed for relation %u",
+			 RelationGetRelid(relation));
+
+	((Form_pg_class) GETSTRUCT(tuple))->relisivm = newstate;
+
+	CatalogTupleUpdate(pgrel, &tuple->t_self, tuple);
+
+	heap_freetuple(tuple);
+	table_close(pgrel, RowExclusiveLock);
+
+	/*
+	 * Advance command counter to make the updated pg_class row locally
+	 * visible.
+	 */
+	CommandCounterIncrement();
+}
+
 /*
  * ExecRefreshMatView -- execute a REFRESH MATERIALIZED VIEW command
  *
@@ -140,9 +287,8 @@ ExecRefreshMatView(RefreshMatViewStmt *stmt, const char *queryString,
 {
 	Oid			matviewOid;
 	Relation	matviewRel;
-	RewriteRule *rule;
-	List	   *actions;
 	Query	   *dataQuery;
+	Query	   *viewQuery;
 	Oid			tableSpace;
 	Oid			relowner;
 	Oid			OIDNewHeap;
@@ -155,6 +301,7 @@ ExecRefreshMatView(RefreshMatViewStmt *stmt, const char *queryString,
 	int			save_sec_context;
 	int			save_nestlevel;
 	ObjectAddress address;
+	bool oldPopulated;
 
 	/* Determine strength of lock needed. */
 	concurrent = stmt->concurrent;
@@ -167,6 +314,7 @@ ExecRefreshMatView(RefreshMatViewStmt *stmt, const char *queryString,
 										  lockmode, 0,
 										  RangeVarCallbackOwnsTable, NULL);
 	matviewRel = table_open(matviewOid, NoLock);
+	oldPopulated = RelationIsPopulated(matviewRel);
 
 	/* Make sure it is a materialized view. */
 	if (matviewRel->rd_rel->relkind != RELKIND_MATVIEW)
@@ -188,32 +336,14 @@ ExecRefreshMatView(RefreshMatViewStmt *stmt, const char *queryString,
 				 errmsg("%s and %s options cannot be used together",
 						"CONCURRENTLY", "WITH NO DATA")));
 
-	/*
-	 * Check that everything is correct for a refresh. Problems at this point
-	 * are internal errors, so elog is sufficient.
-	 */
-	if (matviewRel->rd_rel->relhasrules == false ||
-		matviewRel->rd_rules->numLocks < 1)
-		elog(ERROR,
-			 "materialized view \"%s\" is missing rewrite information",
-			 RelationGetRelationName(matviewRel));
-
-	if (matviewRel->rd_rules->numLocks > 1)
-		elog(ERROR,
-			 "materialized view \"%s\" has too many rules",
-			 RelationGetRelationName(matviewRel));
 
-	rule = matviewRel->rd_rules->rules[0];
-	if (rule->event != CMD_SELECT || !(rule->isInstead))
-		elog(ERROR,
-			 "the rule for materialized view \"%s\" is not a SELECT INSTEAD OF rule",
-			 RelationGetRelationName(matviewRel));
+	viewQuery = get_matview_query(matviewRel);
 
-	actions = rule->actions;
-	if (list_length(actions) != 1)
-		elog(ERROR,
-			 "the rule for materialized view \"%s\" is not a single action",
-			 RelationGetRelationName(matviewRel));
+	/* For IMMV, we need to rewrite matview query */
+	if (!stmt->skipData && RelationIsIVM(matviewRel))
+		dataQuery = rewriteQueryForIMMV(viewQuery,NIL);
+	else
+		dataQuery = viewQuery;
 
 	/*
 	 * Check that there is a unique index with no WHERE clause on one or more
@@ -248,12 +378,6 @@ ExecRefreshMatView(RefreshMatViewStmt *stmt, const char *queryString,
 					 errhint("Create a unique index with no WHERE clause on one or more columns of the materialized view.")));
 	}
 
-	/*
-	 * The stored query was rewritten at the time of the MV definition, but
-	 * has not been scribbled on by the planner.
-	 */
-	dataQuery = linitial_node(Query, actions);
-
 	/*
 	 * Check for active uses of the relation in the current transaction, such
 	 * as open scans.
@@ -294,6 +418,74 @@ ExecRefreshMatView(RefreshMatViewStmt *stmt, const char *queryString,
 		relpersistence = matviewRel->rd_rel->relpersistence;
 	}
 
+	/* delete IMMV triggers. */
+	if (RelationIsIVM(matviewRel) && stmt->skipData )
+	{
+		Relation	tgRel;
+		Relation	depRel;
+		ScanKeyData key;
+		SysScanDesc scan;
+		HeapTuple	tup;
+		ObjectAddresses *immv_triggers;
+
+		immv_triggers = new_object_addresses();
+
+		tgRel = table_open(TriggerRelationId, RowExclusiveLock);
+		depRel = table_open(DependRelationId, RowExclusiveLock);
+
+		/* search triggers that depends on IMMV. */
+		ScanKeyInit(&key,
+					Anum_pg_depend_refobjid,
+					BTEqualStrategyNumber, F_OIDEQ,
+					ObjectIdGetDatum(matviewOid));
+		scan = systable_beginscan(depRel, DependReferenceIndexId, true,
+								  NULL, 1, &key);
+		while ((tup = systable_getnext(scan)) != NULL)
+		{
+			ObjectAddress obj;
+			Form_pg_depend foundDep = (Form_pg_depend) GETSTRUCT(tup);
+
+			if (foundDep->classid == TriggerRelationId)
+			{
+				HeapTuple	tgtup;
+				ScanKeyData tgkey[1];
+				SysScanDesc tgscan;
+				Form_pg_trigger tgform;
+
+				/* Find the trigger name. */
+				ScanKeyInit(&tgkey[0],
+							Anum_pg_trigger_oid,
+							BTEqualStrategyNumber, F_OIDEQ,
+							ObjectIdGetDatum(foundDep->objid));
+
+				tgscan = systable_beginscan(tgRel, TriggerOidIndexId, true,
+											NULL, 1, tgkey);
+				tgtup = systable_getnext(tgscan);
+				if (!HeapTupleIsValid(tgtup))
+					elog(ERROR, "could not find tuple for immv trigger %u", foundDep->objid);
+
+				tgform = (Form_pg_trigger) GETSTRUCT(tgtup);
+
+				/* If trigger is created by IMMV, delete it. */
+				if (strncmp(NameStr(tgform->tgname), "IVM_trigger_", 12) == 0)
+				{
+					obj.classId = foundDep->classid;
+					obj.objectId = foundDep->objid;
+					obj.objectSubId = foundDep->refobjsubid;
+					add_exact_object_address(&obj, immv_triggers);
+				}
+				systable_endscan(tgscan);
+			}
+		}
+		systable_endscan(scan);
+
+		performMultipleDeletions(immv_triggers, DROP_RESTRICT, PERFORM_DELETION_INTERNAL);
+
+		table_close(depRel, RowExclusiveLock);
+		table_close(tgRel, RowExclusiveLock);
+		free_object_addresses(immv_triggers);
+	}
+
 	/*
 	 * Create the transient table that will receive the regenerated data. Lock
 	 * it against access by any other process until commit (by which time it
@@ -313,7 +505,7 @@ ExecRefreshMatView(RefreshMatViewStmt *stmt, const char *queryString,
 
 	/* Generate the data, if wanted. */
 	if (!stmt->skipData)
-		processed = refresh_matview_datafill(dest, dataQuery, queryString);
+		processed = refresh_matview_datafill(dest, dataQuery, NULL, NULL, queryString);
 
 	/* Make the matview match the newly generated data. */
 	if (concurrent)
@@ -348,6 +540,12 @@ ExecRefreshMatView(RefreshMatViewStmt *stmt, const char *queryString,
 			pgstat_count_heap_insert(matviewRel, processed);
 	}
 
+	if (!stmt->skipData && RelationIsIVM(matviewRel) && !oldPopulated)
+	{
+		CreateIndexOnIMMV(viewQuery, matviewRel, false);
+		CreateIvmTriggersOnBaseTables(viewQuery, matviewOid, false);
+	}
+
 	table_close(matviewRel, NoLock);
 
 	/* Roll back any GUC changes */
@@ -382,6 +580,8 @@ ExecRefreshMatView(RefreshMatViewStmt *stmt, const char *queryString,
  */
 static uint64
 refresh_matview_datafill(DestReceiver *dest, Query *query,
+						 QueryEnvironment *queryEnv,
+						 TupleDesc *resultTupleDesc,
 						 const char *queryString)
 {
 	List	   *rewritten;
@@ -418,7 +618,7 @@ refresh_matview_datafill(DestReceiver *dest, Query *query,
 	/* Create a QueryDesc, redirecting output to our tuple receiver */
 	queryDesc = CreateQueryDesc(plan, queryString,
 								GetActiveSnapshot(), InvalidSnapshot,
-								dest, NULL, NULL, 0);
+								dest, NULL, queryEnv ? queryEnv: NULL, 0);
 
 	/* call ExecutorStart to prepare the plan for execution */
 	ExecutorStart(queryDesc, 0);
@@ -428,6 +628,9 @@ refresh_matview_datafill(DestReceiver *dest, Query *query,
 
 	processed = queryDesc->estate->es_processed;
 
+	if (resultTupleDesc)
+		*resultTupleDesc = CreateTupleDescCopy(queryDesc->tupDesc);
+
 	/* and clean up */
 	ExecutorFinish(queryDesc);
 	ExecutorEnd(queryDesc);
@@ -942,3 +1145,1307 @@ CloseMatViewIncrementalMaintenance(void)
 	matview_maintenance_depth--;
 	Assert(matview_maintenance_depth >= 0);
 }
+
+/*
+ * get_matview_query - get the Query from a matview's _RETURN rule.
+ */
+static Query *
+get_matview_query(Relation matviewRel)
+{
+	RewriteRule *rule;
+	List * actions;
+
+	/*
+	 * Check that everything is correct for a refresh. Problems at this point
+	 * are internal errors, so elog is sufficient.
+	 */
+	if (matviewRel->rd_rel->relhasrules == false ||
+		matviewRel->rd_rules->numLocks < 1)
+		elog(ERROR,
+			 "materialized view \"%s\" is missing rewrite information",
+			 RelationGetRelationName(matviewRel));
+
+	if (matviewRel->rd_rules->numLocks > 1)
+		elog(ERROR,
+			 "materialized view \"%s\" has too many rules",
+			 RelationGetRelationName(matviewRel));
+
+	rule = matviewRel->rd_rules->rules[0];
+	if (rule->event != CMD_SELECT || !(rule->isInstead))
+		elog(ERROR,
+			 "the rule for materialized view \"%s\" is not a SELECT INSTEAD OF rule",
+			 RelationGetRelationName(matviewRel));
+
+	actions = rule->actions;
+	if (list_length(actions) != 1)
+		elog(ERROR,
+			 "the rule for materialized view \"%s\" is not a single action",
+			 RelationGetRelationName(matviewRel));
+
+	/*
+	 * The stored query was rewritten at the time of the MV definition, but
+	 * has not been scribbled on by the planner.
+	 */
+	return linitial_node(Query, actions);
+}
+
+
+/* ----------------------------------------------------
+ *		Incremental View Maintenance routines
+ * ---------------------------------------------------
+ */
+
+/*
+ * IVM_immediate_before
+ *
+ * IVM trigger function invoked before base table is modified. If this is
+ * invoked firstly in the same statement, we save the transaction id and the
+ * command id at that time.
+ */
+Datum
+IVM_immediate_before(PG_FUNCTION_ARGS)
+{
+	TriggerData *trigdata = (TriggerData *) fcinfo->context;
+	char	   *matviewOid_text = trigdata->tg_trigger->tgargs[0];
+	char	   *ex_lock_text = trigdata->tg_trigger->tgargs[1];
+	Oid			matviewOid;
+	MV_TriggerHashEntry *entry;
+	bool	found;
+	bool	ex_lock;
+
+	matviewOid = DatumGetObjectId(DirectFunctionCall1(oidin, CStringGetDatum(matviewOid_text)));
+	ex_lock = DatumGetBool(DirectFunctionCall1(boolin, CStringGetDatum(ex_lock_text)));
+
+	/* If the view has more than one tables, we have to use an exclusive lock. */
+	if (ex_lock)
+	{
+		/*
+		 * Wait for concurrent transactions which update this materialized view at
+		 * READ COMMITED. This is needed to see changes committed in other
+		 * transactions. No wait and raise an error at REPEATABLE READ or
+		 * SERIALIZABLE to prevent update anomalies of matviews.
+		 * XXX: dead-lock is possible here.
+		 */
+		if (!IsolationUsesXactSnapshot())
+			LockRelationOid(matviewOid, ExclusiveLock);
+		else if (!ConditionalLockRelationOid(matviewOid, ExclusiveLock))
+		{
+			/* try to throw error by name; relation could be deleted... */
+			char	   *relname = get_rel_name(matviewOid);
+
+			if (!relname)
+				ereport(ERROR,
+						(errcode(ERRCODE_LOCK_NOT_AVAILABLE),
+						errmsg("could not obtain lock on materialized view during incremental maintenance")));
+
+			ereport(ERROR,
+					(errcode(ERRCODE_LOCK_NOT_AVAILABLE),
+					errmsg("could not obtain lock on materialized view \"%s\" during incremental maintenance",
+							relname)));
+		}
+	}
+	else
+		LockRelationOid(matviewOid, RowExclusiveLock);
+
+	/*
+	 * On the first call initialize the hashtable
+	 */
+	if (!mv_trigger_info)
+		mv_InitHashTables();
+
+	entry = (MV_TriggerHashEntry *) hash_search(mv_trigger_info,
+											  (void *) &matviewOid,
+											  HASH_ENTER, &found);
+
+	/* On the first BEFORE to update the view, initialize trigger data */
+	if (!found)
+	{
+		Snapshot snapshot = GetActiveSnapshot();
+
+		entry->matview_id = matviewOid;
+		entry->before_trig_count = 0;
+		entry->after_trig_count = 0;
+		entry->xid = GetCurrentTransactionId();
+		entry->cid = snapshot->curcid;
+		entry->tables = NIL;
+		entry->has_old = false;
+		entry->has_new = false;
+	}
+
+	entry->before_trig_count++;
+
+	return PointerGetDatum(NULL);
+}
+
+/*
+ * IVM_immediate_before
+ *
+ * IVM trigger function invoked after base table is modified.
+ * For each table, tuplestores of transition tables are collected.
+ * and after the last modification
+ */
+Datum
+IVM_immediate_maintenance(PG_FUNCTION_ARGS)
+{
+	TriggerData *trigdata = (TriggerData *) fcinfo->context;
+	Relation	rel;
+	Oid			relid;
+	Oid			matviewOid;
+	Query	   *query;
+	Query	   *rewritten = NULL;
+	char	   *matviewOid_text = trigdata->tg_trigger->tgargs[0];
+	Relation	matviewRel;
+	int old_depth = matview_maintenance_depth;
+
+	Oid			relowner;
+	Tuplestorestate *old_tuplestore = NULL;
+	Tuplestorestate *new_tuplestore = NULL;
+	DestReceiver *dest_new = NULL, *dest_old = NULL;
+	Oid			save_userid;
+	int			save_sec_context;
+	int			save_nestlevel;
+
+	MV_TriggerHashEntry *entry;
+	MV_TriggerTable		*table;
+	bool	found;
+
+	ParseState		 *pstate;
+	QueryEnvironment *queryEnv = create_queryEnv();
+	MemoryContext	oldcxt;
+	ListCell   *lc;
+	int			i;
+
+
+	/* Create a ParseState for rewriting the view definition query */
+	pstate = make_parsestate(NULL);
+	pstate->p_queryEnv = queryEnv;
+	pstate->p_expr_kind = EXPR_KIND_SELECT_TARGET;
+
+	rel = trigdata->tg_relation;
+	relid = rel->rd_id;
+
+	matviewOid = DatumGetObjectId(DirectFunctionCall1(oidin, CStringGetDatum(matviewOid_text)));
+
+	/*
+	 * On the first call initialize the hashtable
+	 */
+	if (!mv_trigger_info)
+		mv_InitHashTables();
+
+	/* get the entry for this materialized view */
+	entry = (MV_TriggerHashEntry *) hash_search(mv_trigger_info,
+											  (void *) &matviewOid,
+											  HASH_FIND, &found);
+	Assert (found && entry != NULL);
+	entry->after_trig_count++;
+
+	/* search the entry for the modified table and create new entry if not found */
+	found = false;
+	foreach(lc, entry->tables)
+	{
+		table = (MV_TriggerTable *) lfirst(lc);
+		if (table->table_id == relid)
+		{
+			found = true;
+			break;
+		}
+	}
+	if (!found)
+	{
+		oldcxt = MemoryContextSwitchTo(TopTransactionContext);
+
+		table = (MV_TriggerTable *) palloc0(sizeof(MV_TriggerTable));
+		table->table_id = relid;
+		table->old_tuplestores = NIL;
+		table->new_tuplestores = NIL;
+		table->old_rtes = NIL;
+		table->new_rtes = NIL;
+		table->rte_indexes = NIL;
+		entry->tables = lappend(entry->tables, table);
+
+		MemoryContextSwitchTo(oldcxt);
+	}
+
+	/* Save the transition tables and make a request to not free immediately */
+	if (trigdata->tg_oldtable)
+	{
+		oldcxt = MemoryContextSwitchTo(TopTransactionContext);
+		table->old_tuplestores = lappend(table->old_tuplestores, trigdata->tg_oldtable);
+		entry->has_old = true;
+		MemoryContextSwitchTo(oldcxt);
+	}
+	if (trigdata->tg_newtable)
+	{
+		oldcxt = MemoryContextSwitchTo(TopTransactionContext);
+		table->new_tuplestores = lappend(table->new_tuplestores, trigdata->tg_newtable);
+		entry->has_new = true;
+		MemoryContextSwitchTo(oldcxt);
+	}
+	if (entry->has_new || entry->has_old)
+	{
+		CmdType cmd;
+
+		if (TRIGGER_FIRED_BY_INSERT(trigdata->tg_event))
+			cmd = CMD_INSERT;
+		else if (TRIGGER_FIRED_BY_DELETE(trigdata->tg_event))
+			cmd = CMD_DELETE;
+		else if (TRIGGER_FIRED_BY_UPDATE(trigdata->tg_event))
+			cmd = CMD_UPDATE;
+		else
+			elog(ERROR,"unsupported trigger type");
+
+		/* Prolong lifespan of transition tables to the end of the last AFTER trigger */
+		SetTransitionTablePreserved(relid, cmd);
+	}
+
+
+	/* If this is not the last AFTER trigger call, immediately exit. */
+	Assert (entry->before_trig_count >= entry->after_trig_count);
+	if (entry->before_trig_count != entry->after_trig_count)
+		return PointerGetDatum(NULL);
+
+	/*
+	 * If this is the last AFTER trigger call, continue and update the view.
+	 */
+
+	/*
+	 * Advance command counter to make the updated base table row locally
+	 * visible.
+	 */
+	CommandCounterIncrement();
+
+	matviewRel = table_open(matviewOid, NoLock);
+
+	/* get view query*/
+	query = get_matview_query(matviewRel);
+
+	/* Make sure it is a materialized view. */
+	Assert(matviewRel->rd_rel->relkind == RELKIND_MATVIEW);
+
+	/*
+	 * Get and push the latast snapshot to see any changes which is committed
+	 * during waiting in other transactions at READ COMMITTED level.
+	 */
+	PushActiveSnapshot(GetTransactionSnapshot());
+
+	/*
+	 * Check for active uses of the relation in the current transaction, such
+	 * as open scans.
+	 *
+	 * NB: We count on this to protect us against problems with refreshing the
+	 * data using TABLE_INSERT_FROZEN.
+	 */
+	CheckTableNotInUse(matviewRel, "refresh a materialized view incrementally");
+
+	/*
+	 * Switch to the owner's userid, so that any functions are run as that
+	 * user.  Also arrange to make GUC variable changes local to this command.
+	 * We will switch modes when we are about to execute user code.
+	 */
+	relowner = matviewRel->rd_rel->relowner;
+	GetUserIdAndSecContext(&save_userid, &save_sec_context);
+	SetUserIdAndSecContext(relowner,
+						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
+	save_nestlevel = NewGUCNestLevel();
+
+	/*
+	 * rewrite query for calculating deltas
+	 */
+
+	rewritten = copyObject(query);
+
+	/* Replace resnames in a target list with materialized view's attnames */
+	i = 0;
+	foreach (lc, rewritten->targetList)
+	{
+		TargetEntry *tle = (TargetEntry *) lfirst(lc);
+		Form_pg_attribute attr = TupleDescAttr(matviewRel->rd_att, i);
+		char *resname = NameStr(attr->attname);
+
+		tle->resname = pstrdup(resname);
+		i++;
+	}
+
+	/* Set all tables in the query to pre-update state */
+	rewritten = rewrite_query_for_preupdate_state(rewritten, entry->tables,
+												  entry->xid, entry->cid,
+												  pstate);
+	/* Rewrite for DISTINCT clause */
+	rewritten = rewrite_query_for_distinct(rewritten, pstate);
+
+	/* Create tuplestores to store view deltas */
+	if (entry->has_old)
+	{
+		oldcxt = MemoryContextSwitchTo(TopTransactionContext);
+
+		old_tuplestore = tuplestore_begin_heap(false, false, work_mem);
+		dest_old = CreateDestReceiver(DestTuplestore);
+		SetTuplestoreDestReceiverParams(dest_old,
+									old_tuplestore,
+									TopTransactionContext,
+									false,
+									NULL,
+									NULL);
+
+		MemoryContextSwitchTo(oldcxt);
+	}
+	if (entry->has_new)
+	{
+		oldcxt = MemoryContextSwitchTo(TopTransactionContext);
+
+		new_tuplestore = tuplestore_begin_heap(false, false, work_mem);
+		dest_new = CreateDestReceiver(DestTuplestore);
+		SetTuplestoreDestReceiverParams(dest_new,
+									new_tuplestore,
+									TopTransactionContext,
+									false,
+									NULL,
+									NULL);
+		MemoryContextSwitchTo(oldcxt);
+	}
+
+	/* for all modified tables */
+	foreach(lc, entry->tables)
+	{
+		ListCell *lc2;
+
+		table = (MV_TriggerTable *) lfirst(lc);
+
+		/* loop for self-join */
+		foreach(lc2, table->rte_indexes)
+		{
+			int	rte_index = lfirst_int(lc2);
+			TupleDesc		tupdesc_old;
+			TupleDesc		tupdesc_new;
+			bool	use_count = false;
+			char   *count_colname = NULL;
+
+			count_colname = pstrdup("__ivm_count__");
+
+			if (query->distinctClause)
+				use_count = true;
+
+			/* calculate delta tables */
+			calc_delta(table, rte_index, rewritten, dest_old, dest_new,
+					   &tupdesc_old, &tupdesc_new, queryEnv);
+
+			/* Set the table in the query to post-update state */
+			rewritten = rewrite_query_for_postupdate_state(rewritten, table, rte_index);
+
+			PG_TRY();
+			{
+				/* apply the delta tables to the materialized view */
+				apply_delta(matviewOid, old_tuplestore, new_tuplestore,
+							tupdesc_old, tupdesc_new, query, use_count,
+							count_colname);
+			}
+			PG_CATCH();
+			{
+				matview_maintenance_depth = old_depth;
+				PG_RE_THROW();
+			}
+			PG_END_TRY();
+
+			/* clear view delta tuplestores */
+			if (old_tuplestore)
+				tuplestore_clear(old_tuplestore);
+			if (new_tuplestore)
+				tuplestore_clear(new_tuplestore);
+		}
+	}
+
+	/* Clean up hash entry and delete tuplestores */
+	clean_up_IVM_hash_entry(entry);
+	if (old_tuplestore)
+	{
+		dest_old->rDestroy(dest_old);
+		tuplestore_end(old_tuplestore);
+	}
+	if (new_tuplestore)
+	{
+		dest_new->rDestroy(dest_new);
+		tuplestore_end(new_tuplestore);
+	}
+
+	/* Pop the original snapshot. */
+	PopActiveSnapshot();
+
+	table_close(matviewRel, NoLock);
+
+	/* Roll back any GUC changes */
+	AtEOXact_GUC(false, save_nestlevel);
+
+	/* Restore userid and security context */
+	SetUserIdAndSecContext(save_userid, save_sec_context);
+
+	return PointerGetDatum(NULL);
+}
+
+/*
+ * rewrite_query_for_preupdate_state
+ *
+ * Rewrite the query so that base tables' RTEs will represent "pre-update"
+ * state of tables. This is necessary to calculate view delta after multiple
+ * tables are modified. xid and cid are the transaction id and command id
+ * before the first table was modified.
+ */
+static Query*
+rewrite_query_for_preupdate_state(Query *query, List *tables,
+								  TransactionId xid, CommandId cid,
+								  ParseState *pstate)
+{
+	ListCell *lc;
+	int num_rte = list_length(query->rtable);
+	int i;
+
+
+	/* register delta ENRs */
+	register_delta_ENRs(pstate, query, tables);
+
+	/* XXX: Is necessary? Is this right timing? */
+	AcquireRewriteLocks(query, true, false);
+
+	i = 1;
+	foreach(lc, query->rtable)
+	{
+		RangeTblEntry *r = (RangeTblEntry*) lfirst(lc);
+
+		ListCell *lc2;
+		foreach(lc2, tables)
+		{
+			MV_TriggerTable *table = (MV_TriggerTable *) lfirst(lc2);
+			/*
+			 * if the modified table is found then replace the original RTE with
+			 * "pre-state" RTE and append its index to the list.
+			 */
+			if (r->relid == table->table_id)
+			{
+				lfirst(lc) = get_prestate_rte(r, table, xid, cid, pstate->p_queryEnv);
+				table->rte_indexes = lappend_int(table->rte_indexes, i);
+				break;
+			}
+		}
+
+		/* finish the loop if we processed all RTE included in the original query */
+		if (i++ >= num_rte)
+			break;
+	}
+
+	return query;
+}
+
+/*
+ * register_delta_ENRs
+ *
+ * For all modified tables, make ENRs for their transition tables
+ * and register them to the queryEnv. ENR's RTEs are also appended
+ * into the list in query tree.
+ */
+static void
+register_delta_ENRs(ParseState *pstate, Query *query, List *tables)
+{
+	QueryEnvironment *queryEnv = pstate->p_queryEnv;
+	ListCell *lc;
+	RangeTblEntry	*rte;
+
+	foreach(lc, tables)
+	{
+		MV_TriggerTable *table = (MV_TriggerTable *) lfirst(lc);
+		ListCell *lc2;
+		int count;
+
+		count = 0;
+		foreach(lc2, table->old_tuplestores)
+		{
+			Tuplestorestate *oldtable = (Tuplestorestate *) lfirst(lc2);
+			EphemeralNamedRelation enr =
+				palloc(sizeof(EphemeralNamedRelationData));
+			ParseNamespaceItem *nsitem;
+
+			enr->md.name = make_delta_enr_name("old", table->table_id, count);
+			enr->md.reliddesc = table->table_id;
+			enr->md.tupdesc = NULL;
+			enr->md.enrtype = ENR_NAMED_TUPLESTORE;
+			enr->md.enrtuples = tuplestore_tuple_count(oldtable);
+			enr->reldata = oldtable;
+			register_ENR(queryEnv, enr);
+
+			nsitem = addRangeTableEntryForENR(pstate, makeRangeVar(NULL, enr->md.name, -1), true);
+			rte = nsitem->p_rte;
+			/* if base table has RLS, set security condition to enr */
+			rte->securityQuals = get_securityQuals(table->table_id, list_length(query->rtable) + 1, query);
+
+			query->rtable = lappend(query->rtable, rte);
+			table->old_rtes = lappend(table->old_rtes, rte);
+
+			count++;
+		}
+
+		count = 0;
+		foreach(lc2, table->new_tuplestores)
+		{
+			Tuplestorestate *newtable = (Tuplestorestate *) lfirst(lc2);
+			EphemeralNamedRelation enr =
+				palloc(sizeof(EphemeralNamedRelationData));
+			ParseNamespaceItem *nsitem;
+
+			enr->md.name = make_delta_enr_name("new", table->table_id, count);
+			enr->md.reliddesc = table->table_id;
+			enr->md.tupdesc = NULL;
+			enr->md.enrtype = ENR_NAMED_TUPLESTORE;
+			enr->md.enrtuples = tuplestore_tuple_count(newtable);
+			enr->reldata = newtable;
+			register_ENR(queryEnv, enr);
+
+			nsitem = addRangeTableEntryForENR(pstate, makeRangeVar(NULL, enr->md.name, -1), true);
+			rte = nsitem->p_rte;
+			/* if base table has RLS, set security condition to enr*/
+			rte->securityQuals = get_securityQuals(table->table_id, list_length(query->rtable) + 1, query);
+
+			query->rtable = lappend(query->rtable, rte);
+			table->new_rtes = lappend(table->new_rtes, rte);
+
+			count++;
+		}
+	}
+}
+
+/*
+ * get_prestate_rte
+ *
+ * Rewrite RTE of the modified table to a subquery which represents
+ * "pre-state" table. The original RTE is saved in table->rte_original.
+ */
+static RangeTblEntry*
+get_prestate_rte(RangeTblEntry *rte, MV_TriggerTable *table,
+				 TransactionId xid, CommandId cid,
+				 QueryEnvironment *queryEnv)
+{
+	StringInfoData str;
+	RawStmt *raw;
+	Query *sub;
+	Relation rel;
+	ParseState *pstate;
+	char *relname;
+	int i;
+
+	pstate = make_parsestate(NULL);
+	pstate->p_queryEnv = queryEnv;
+	pstate->p_expr_kind = EXPR_KIND_SELECT_TARGET;
+
+	/*
+	 * We can use NoLock here since AcquireRewriteLocks should
+	 * have locked the rel already.
+	 */
+	rel = table_open(table->table_id, NoLock);
+	relname = quote_qualified_identifier(
+					get_namespace_name(RelationGetNamespace(rel)),
+									   RelationGetRelationName(rel));
+	table_close(rel, NoLock);
+
+	initStringInfo(&str);
+	appendStringInfo(&str,
+		"SELECT t.* FROM %s t"
+		" WHERE (age(t.xmin) - age(%u::text::xid) > 0) OR"
+		" (t.xmin = %u AND t.cmin::text::int < %u)",
+			relname, xid, xid, cid);
+
+	for (i = 0; i < list_length(table->old_tuplestores); i++)
+	{
+		appendStringInfo(&str, " UNION ALL ");
+		appendStringInfo(&str," SELECT * FROM %s",
+			make_delta_enr_name("old", table->table_id, i));
+	}
+
+	raw = (RawStmt*)linitial(raw_parser(str.data, RAW_PARSE_DEFAULT));
+	sub = transformStmt(pstate, raw->stmt);
+
+	/* If this query has setOperations, RTEs in rtables has a subquery which contains ENR */
+	if (sub->setOperations != NULL)
+	{
+		ListCell *lc;
+
+		/* add securityQuals for tuplestores */
+		foreach (lc, sub->rtable)
+		{
+			RangeTblEntry *rte;
+			RangeTblEntry *sub_rte;
+
+			rte = (RangeTblEntry *)lfirst(lc);
+			Assert(rte->subquery != NULL);
+
+			sub_rte = (RangeTblEntry *)linitial(rte->subquery->rtable);
+			if (sub_rte->rtekind == RTE_NAMEDTUPLESTORE)
+				/* rt_index is always 1, bacause subquery has enr_rte only */
+				sub_rte->securityQuals = get_securityQuals(sub_rte->relid, 1, sub);
+		}
+	}
+
+	/* save the original RTE */
+	table->original_rte = copyObject(rte);
+
+	rte->rtekind = RTE_SUBQUERY;
+	rte->subquery = sub;
+	rte->security_barrier = false;
+	/* Clear fields that should not be set in a subquery RTE */
+	rte->relid = InvalidOid;
+	rte->relkind = 0;
+	rte->rellockmode = 0;
+	rte->tablesample = NULL;
+	rte->inh = false;			/* must not be set for a subquery */
+
+	rte->requiredPerms = 0;		/* no permission check on subquery itself */
+	rte->checkAsUser = InvalidOid;
+	rte->selectedCols = NULL;
+	rte->insertedCols = NULL;
+	rte->updatedCols = NULL;
+	rte->extraUpdatedCols = NULL;
+
+	return rte;
+}
+
+/*
+ * make_delta_enr_name
+ *
+ * Make a name for ENR of a transition table from the base table's oid.
+ * prefix will be "new" or "old" depending on its transition table kind..
+ */
+static char*
+make_delta_enr_name(const char *prefix, Oid relid, int count)
+{
+	char buf[NAMEDATALEN];
+	char *name;
+
+	snprintf(buf, NAMEDATALEN, "__ivm_%s_%u_%u", prefix, relid, count);
+	name = pstrdup(buf);
+
+	return name;
+}
+
+/*
+ * union_ENRs
+ *
+ * Make a single table delta by unionning all transition tables of the modified table
+ * whose RTE is specified by
+ */
+static RangeTblEntry*
+union_ENRs(RangeTblEntry *rte, Oid relid, List *enr_rtes, const char *prefix,
+		   QueryEnvironment *queryEnv)
+{
+	StringInfoData str;
+	ParseState	*pstate;
+	RawStmt *raw;
+	Query *sub;
+	int	i;
+	RangeTblEntry *enr_rte;
+
+	/* Create a ParseState for rewriting the view definition query */
+	pstate = make_parsestate(NULL);
+	pstate->p_queryEnv = queryEnv;
+	pstate->p_expr_kind = EXPR_KIND_SELECT_TARGET;
+
+	initStringInfo(&str);
+
+	for (i = 0; i < list_length(enr_rtes); i++)
+	{
+		if (i > 0)
+			appendStringInfo(&str, " UNION ALL ");
+
+		appendStringInfo(&str,
+			" SELECT * FROM %s",
+			make_delta_enr_name(prefix, relid, i));
+	}
+
+	raw = (RawStmt*)linitial(raw_parser(str.data, RAW_PARSE_DEFAULT));
+	sub = transformStmt(pstate, raw->stmt);
+
+	rte->rtekind = RTE_SUBQUERY;
+	rte->subquery = sub;
+	rte->security_barrier = false;
+	/* Clear fields that should not be set in a subquery RTE */
+	rte->relid = InvalidOid;
+	rte->relkind = 0;
+	rte->rellockmode = 0;
+	rte->tablesample = NULL;
+	rte->inh = false;			/* must not be set for a subquery */
+
+	rte->requiredPerms = 0;		/* no permission check on subquery itself */
+	rte->checkAsUser = InvalidOid;
+	rte->selectedCols = NULL;
+	rte->insertedCols = NULL;
+	rte->updatedCols = NULL;
+	rte->extraUpdatedCols = NULL;
+	/* if base table has RLS, set security condition to enr*/
+	enr_rte = (RangeTblEntry *)linitial(sub->rtable);
+	/* rt_index is always 1, bacause subquery has enr_rte only */
+	enr_rte->securityQuals = get_securityQuals(relid, 1, sub);
+
+	return rte;
+}
+
+/*
+ * rewrite_query_for_distinct
+ *
+ * Rewrite query for counting DISTINCT clause.
+ */
+static Query *
+rewrite_query_for_distinct(Query *query, ParseState *pstate)
+{
+	TargetEntry *tle_count;
+	FuncCall *fn;
+	Node *node;
+
+	/* Add count(*) for counting distinct tuples in views */
+	fn = makeFuncCall(list_make1(makeString("count")), NIL, COERCE_EXPLICIT_CALL, -1);
+	fn->agg_star = true;
+	if (!query->groupClause && !query->hasAggs)
+		query->groupClause = transformDistinctClause(NULL, &query->targetList, query->sortClause, false);
+
+	node = ParseFuncOrColumn(pstate, fn->funcname, NIL, NULL, fn, false, -1);
+
+	tle_count = makeTargetEntry((Expr *) node,
+								list_length(query->targetList) + 1,
+								pstrdup("__ivm_count__"),
+								false);
+	query->targetList = lappend(query->targetList, tle_count);
+	query->hasAggs = true;
+
+	return query;
+}
+
+/*
+ * calc_delta
+ *
+ * Calculate view deltas generated under the modification of a table specified
+ * by the RTE index.
+ */
+static void
+calc_delta(MV_TriggerTable *table, int rte_index, Query *query,
+			DestReceiver *dest_old, DestReceiver *dest_new,
+			TupleDesc *tupdesc_old, TupleDesc *tupdesc_new,
+			QueryEnvironment *queryEnv)
+{
+	ListCell *lc = list_nth_cell(query->rtable, rte_index - 1);
+	RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
+
+	/* Generate old delta */
+	if (list_length(table->old_rtes) > 0)
+	{
+		/* Replace the modified table with the old delta table and calculate the old view delta. */
+		lfirst(lc) = union_ENRs(rte, table->table_id, table->old_rtes, "old", queryEnv);
+		refresh_matview_datafill(dest_old, query, queryEnv, tupdesc_old, "");
+	}
+
+	/* Generate new delta */
+	if (list_length(table->new_rtes) > 0)
+	{
+		/* Replace the modified table with the new delta table and calculate the new view delta*/
+		lfirst(lc) = union_ENRs(rte, table->table_id, table->new_rtes, "new", queryEnv);
+		refresh_matview_datafill(dest_new, query, queryEnv, tupdesc_new, "");
+	}
+}
+
+/*
+ * rewrite_query_for_postupdate_state
+ *
+ * Rewrite the query so that the specified base table's RTEs will represent
+ * "post-update" state of tables. This is called after the view delta
+ * calculation due to changes on this table finishes.
+ */
+static Query*
+rewrite_query_for_postupdate_state(Query *query, MV_TriggerTable *table, int rte_index)
+{
+	ListCell *lc = list_nth_cell(query->rtable, rte_index - 1);
+
+	/* Retore the original RTE */
+	lfirst(lc) = table->original_rte;
+
+	return query;
+}
+
+/*
+ * apply_delta
+ *
+ * Apply deltas to the materialized view. In outer join cases, this requires
+ * the view maintenance graph.
+ */
+static void
+apply_delta(Oid matviewOid, Tuplestorestate *old_tuplestores, Tuplestorestate *new_tuplestores,
+			TupleDesc tupdesc_old, TupleDesc tupdesc_new,
+			Query *query, bool use_count, char *count_colname)
+{
+	StringInfoData querybuf;
+	StringInfoData target_list_buf;
+	Relation	matviewRel;
+	char	   *matviewname;
+	ListCell	*lc;
+	int			i;
+	List	   *keys = NIL;
+
+
+	/*
+	 * get names of the materialized view and delta tables
+	 */
+
+	matviewRel = table_open(matviewOid, NoLock);
+	matviewname = quote_qualified_identifier(get_namespace_name(RelationGetNamespace(matviewRel)),
+											 RelationGetRelationName(matviewRel));
+
+	/*
+	 * Build parts of the maintenance queries
+	 */
+
+	initStringInfo(&querybuf);
+	initStringInfo(&target_list_buf);
+
+	/* build string of target list */
+	for (i = 0; i < matviewRel->rd_att->natts; i++)
+	{
+		Form_pg_attribute attr = TupleDescAttr(matviewRel->rd_att, i);
+		char   *resname = NameStr(attr->attname);
+
+		if (i != 0)
+			appendStringInfo(&target_list_buf, ", ");
+		appendStringInfo(&target_list_buf, "%s", quote_qualified_identifier(NULL, resname));
+	}
+
+	i = 0;
+	foreach (lc, query->targetList)
+	{
+		TargetEntry *tle = (TargetEntry *) lfirst(lc);
+		Form_pg_attribute attr = TupleDescAttr(matviewRel->rd_att, i);
+
+		i++;
+
+		if (tle->resjunk)
+			continue;
+
+		keys = lappend(keys, attr);
+	}
+
+	/* Start maintaining the materialized view. */
+	OpenMatViewIncrementalMaintenance();
+
+	/* Open SPI context. */
+	if (SPI_connect() != SPI_OK_CONNECT)
+		elog(ERROR, "SPI_connect failed");
+
+	/* For tuple deletion */
+	if (old_tuplestores && tuplestore_tuple_count(old_tuplestores) > 0)
+	{
+		EphemeralNamedRelation enr = palloc(sizeof(EphemeralNamedRelationData));
+		int				rc;
+
+		/* convert tuplestores to ENR, and register for SPI */
+		enr->md.name = pstrdup(OLD_DELTA_ENRNAME);
+		enr->md.reliddesc = InvalidOid;
+		enr->md.tupdesc = tupdesc_old;
+		enr->md.enrtype = ENR_NAMED_TUPLESTORE;
+		enr->md.enrtuples = tuplestore_tuple_count(old_tuplestores);
+		enr->reldata = old_tuplestores;
+
+		rc = SPI_register_relation(enr);
+		if (rc != SPI_OK_REL_REGISTER)
+			elog(ERROR, "SPI_register failed");
+
+		if (use_count)
+			/* apply old delta and get rows to be recalculated */
+			apply_old_delta_with_count(matviewname, OLD_DELTA_ENRNAME,
+									   keys, count_colname);
+		else
+			apply_old_delta(matviewname, OLD_DELTA_ENRNAME, keys);
+
+	}
+	/* For tuple insertion */
+	if (new_tuplestores && tuplestore_tuple_count(new_tuplestores) > 0)
+	{
+		EphemeralNamedRelation enr = palloc(sizeof(EphemeralNamedRelationData));
+		int rc;
+
+		/* convert tuplestores to ENR, and register for SPI */
+		enr->md.name = pstrdup(NEW_DELTA_ENRNAME);
+		enr->md.reliddesc = InvalidOid;
+		enr->md.tupdesc = tupdesc_new;;
+		enr->md.enrtype = ENR_NAMED_TUPLESTORE;
+		enr->md.enrtuples = tuplestore_tuple_count(new_tuplestores);
+		enr->reldata = new_tuplestores;
+
+		rc = SPI_register_relation(enr);
+		if (rc != SPI_OK_REL_REGISTER)
+			elog(ERROR, "SPI_register failed");
+
+		/* apply new delta */
+		if (use_count)
+			apply_new_delta_with_count(matviewname, NEW_DELTA_ENRNAME,
+								keys, &target_list_buf, count_colname);
+		else
+			apply_new_delta(matviewname, NEW_DELTA_ENRNAME, &target_list_buf);
+	}
+
+	/* We're done maintaining the materialized view. */
+	CloseMatViewIncrementalMaintenance();
+
+	table_close(matviewRel, NoLock);
+
+	/* Close SPI context. */
+	if (SPI_finish() != SPI_OK_FINISH)
+		elog(ERROR, "SPI_finish failed");
+}
+
+/*
+ * apply_old_delta_with_count
+ *
+ * Execute a query for applying a delta table given by deltname_old
+ * which contains tuples to be deleted from to a materialized view given by
+ * matviewname.  This is used when counting is required, that is, the view
+ * has aggregate or distinct.
+ */
+static void
+apply_old_delta_with_count(const char *matviewname, const char *deltaname_old,
+				List *keys, const char *count_colname)
+{
+	StringInfoData	querybuf;
+	char   *match_cond;
+
+	/* build WHERE condition for searching tuples to be deleted */
+	match_cond = get_matching_condition_string(keys);
+
+	/* Search for matching tuples from the view and update or delete if found. */
+	initStringInfo(&querybuf);
+	appendStringInfo(&querybuf,
+					"WITH t AS ("			/* collecting tid of target tuples in the view */
+						"SELECT diff.%s, "			/* count column */
+								"(diff.%s OPERATOR(pg_catalog.=) mv.%s) AS for_dlt, "
+								"mv.ctid "
+						"FROM %s AS mv, %s AS diff "
+						"WHERE %s"					/* tuple matching condition */
+					"), updt AS ("			/* update a tuple if this is not to be deleted */
+						"UPDATE %s AS mv SET %s = mv.%s OPERATOR(pg_catalog.-) t.%s "
+						"FROM t WHERE mv.ctid OPERATOR(pg_catalog.=) t.ctid AND NOT for_dlt "
+					")"
+					/* delete a tuple if this is to be deleted */
+					"DELETE FROM %s AS mv USING t "
+					"WHERE mv.ctid OPERATOR(pg_catalog.=) t.ctid AND for_dlt",
+					count_colname,
+					count_colname, count_colname,
+					matviewname, deltaname_old,
+					match_cond,
+					matviewname, count_colname, count_colname, count_colname,
+					matviewname);
+
+	if (SPI_exec(querybuf.data, 0) != SPI_OK_DELETE)
+		elog(ERROR, "SPI_exec failed: %s", querybuf.data);
+}
+
+/*
+ * apply_old_delta
+ *
+ * Execute a query for applying a delta table given by deltname_old
+ * which contains tuples to be deleted from to a materialized view given by
+ * matviewname.  This is used when counting is not required.
+ */
+static void
+apply_old_delta(const char *matviewname, const char *deltaname_old,
+				List *keys)
+{
+	StringInfoData	querybuf;
+	StringInfoData	keysbuf;
+	char   *match_cond;
+	ListCell *lc;
+
+	/* build WHERE condition for searching tuples to be deleted */
+	match_cond = get_matching_condition_string(keys);
+
+	/* build string of keys list */
+	initStringInfo(&keysbuf);
+	foreach (lc, keys)
+	{
+		Form_pg_attribute attr = (Form_pg_attribute) lfirst(lc);
+		char   *resname = NameStr(attr->attname);
+		appendStringInfo(&keysbuf, "%s", quote_qualified_identifier("mv", resname));
+		if (lnext(keys, lc))
+			appendStringInfo(&keysbuf, ", ");
+	}
+
+	/* Search for matching tuples from the view and update or delete if found. */
+	initStringInfo(&querybuf);
+	appendStringInfo(&querybuf,
+	"DELETE FROM %s WHERE ctid IN ("
+		"SELECT tid FROM (SELECT row_number() over (partition by %s) AS \"__ivm_row_number__\","
+								  "mv.ctid AS tid,"
+								  "diff.\"__ivm_count__\""
+						 "FROM %s AS mv, %s AS diff "
+						 "WHERE %s) v "
+					"WHERE v.\"__ivm_row_number__\" OPERATOR(pg_catalog.<=) v.\"__ivm_count__\")",
+					matviewname,
+					keysbuf.data,
+					matviewname, deltaname_old,
+					match_cond);
+
+	if (SPI_exec(querybuf.data, 0) != SPI_OK_DELETE)
+		elog(ERROR, "SPI_exec failed: %s", querybuf.data);
+}
+
+/*
+ * apply_new_delta_with_count
+ *
+ * Execute a query for applying a delta table given by deltname_new
+ * which contains tuples to be inserted into a materialized view given by
+ * matviewname.  This is used when counting is required, that is, the view
+ * has aggregate or distinct. Also, when a table in EXISTS sub queries
+ * is modified.
+ */
+static void
+apply_new_delta_with_count(const char *matviewname, const char* deltaname_new,
+				List *keys, StringInfo target_list, const char* count_colname)
+{
+	StringInfoData	querybuf;
+	StringInfoData	returning_keys;
+	ListCell	*lc;
+	char	*match_cond = "";
+
+	/* build WHERE condition for searching tuples to be updated */
+	match_cond = get_matching_condition_string(keys);
+
+	/* build string of keys list */
+	initStringInfo(&returning_keys);
+	if (keys)
+	{
+		foreach (lc, keys)
+		{
+			Form_pg_attribute attr = (Form_pg_attribute) lfirst(lc);
+			char   *resname = NameStr(attr->attname);
+			appendStringInfo(&returning_keys, "%s", quote_qualified_identifier("mv", resname));
+			if (lnext(keys, lc))
+				appendStringInfo(&returning_keys, ", ");
+		}
+	}
+	else
+		appendStringInfo(&returning_keys, "NULL");
+
+	/* Search for matching tuples from the view and update if found or insert if not. */
+	initStringInfo(&querybuf);
+	appendStringInfo(&querybuf,
+					"WITH updt AS ("		/* update a tuple if this exists in the view */
+						"UPDATE %s AS mv SET %s = mv.%s OPERATOR(pg_catalog.+) diff.%s "
+						"FROM %s AS diff "
+						"WHERE %s "					/* tuple matching condition */
+						"RETURNING %s"				/* returning keys of updated tuples */
+					") INSERT INTO %s (%s)"	/* insert a new tuple if this doesn't existw */
+						"SELECT %s FROM %s AS diff "
+						"WHERE NOT EXISTS (SELECT 1 FROM updt AS mv WHERE %s);",
+					matviewname, count_colname, count_colname, count_colname,
+					deltaname_new,
+					match_cond,
+					returning_keys.data,
+					matviewname, target_list->data,
+					target_list->data, deltaname_new,
+					match_cond);
+
+	if (SPI_exec(querybuf.data, 0) != SPI_OK_INSERT)
+		elog(ERROR, "SPI_exec failed: %s", querybuf.data);
+}
+
+/*
+ * apply_new_delta
+ *
+ * Execute a query for applying a delta table given by deltname_new
+ * which contains tuples to be inserted into a materialized view given by
+ * matviewname.  This is used when counting is not required.
+ */
+static void
+apply_new_delta(const char *matviewname, const char *deltaname_new,
+				StringInfo target_list)
+{
+	StringInfoData	querybuf;
+
+	/* Search for matching tuples from the view and update or delete if found. */
+	initStringInfo(&querybuf);
+	appendStringInfo(&querybuf,
+					"INSERT INTO %s (%s) SELECT %s FROM ("
+						"SELECT diff.*, generate_series(1, diff.\"__ivm_count__\") "
+						"FROM %s AS diff) AS v",
+					matviewname, target_list->data, target_list->data,
+					deltaname_new);
+
+	if (SPI_exec(querybuf.data, 0) != SPI_OK_INSERT)
+		elog(ERROR, "SPI_exec failed: %s", querybuf.data);
+}
+
+/*
+ * get_matching_condition_string
+ *
+ * Build a predicate string for looking for a tuple with given keys.
+ */
+static char *
+get_matching_condition_string(List *keys)
+{
+	StringInfoData match_cond;
+	ListCell	*lc;
+
+	/* If there is no key columns, the condition is always true. */
+	if (keys == NIL)
+		return "true";
+
+	initStringInfo(&match_cond);
+	foreach (lc, keys)
+	{
+		Form_pg_attribute attr = (Form_pg_attribute) lfirst(lc);
+		char   *resname = NameStr(attr->attname);
+		char   *mv_resname = quote_qualified_identifier("mv", resname);
+		char   *diff_resname = quote_qualified_identifier("diff", resname);
+		Oid		typid = attr->atttypid;
+
+		/* Considering NULL values, we can not use simple = operator. */
+		appendStringInfo(&match_cond, "(");
+		generate_equal(&match_cond, typid, mv_resname, diff_resname);
+		appendStringInfo(&match_cond, " OR (%s IS NULL AND %s IS NULL))",
+						 mv_resname, diff_resname);
+
+		if (lnext(keys, lc))
+			appendStringInfo(&match_cond, " AND ");
+	}
+
+	return match_cond.data;
+}
+
+/*
+ * generate_equals
+ *
+ * Generate an equality clause using given operands' default equality
+ * operator.
+ */
+static void
+generate_equal(StringInfo querybuf, Oid opttype,
+			   const char *leftop, const char *rightop)
+{
+	TypeCacheEntry *typentry;
+
+	typentry = lookup_type_cache(opttype, TYPECACHE_EQ_OPR);
+	if (!OidIsValid(typentry->eq_opr))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_FUNCTION),
+				 errmsg("could not identify an equality operator for type %s",
+						format_type_be(opttype))));
+
+	generate_operator_clause(querybuf,
+							 leftop, opttype,
+							 typentry->eq_opr,
+							 rightop, opttype);
+}
+
+/*
+ * mv_InitHashTables
+ */
+static void
+mv_InitHashTables(void)
+{
+	HASHCTL		ctl;
+
+	memset(&ctl, 0, sizeof(ctl));
+	ctl.keysize = sizeof(Oid);
+	ctl.entrysize = sizeof(MV_TriggerHashEntry);
+	mv_trigger_info = hash_create("MV trigger info",
+								 MV_INIT_QUERYHASHSIZE,
+								 &ctl, HASH_ELEM | HASH_BLOBS);
+}
+
+/*
+ * AtAbort_IVM
+ *
+ * Clean up hash entries for all materialized views. This is called at
+ * transaction abort.
+ */
+void
+AtAbort_IVM()
+{
+	HASH_SEQ_STATUS seq;
+	MV_TriggerHashEntry *entry;
+
+	if (mv_trigger_info)
+	{
+		hash_seq_init(&seq, mv_trigger_info);
+		while ((entry = hash_seq_search(&seq)) != NULL)
+			clean_up_IVM_hash_entry(entry);
+	}
+}
+
+/*
+ * clean_up_IVM_hash_entry
+ *
+ * Clean up tuple stores and hash entries for a materialized view after its
+ * maintenance finished.
+ */
+static void
+clean_up_IVM_hash_entry(MV_TriggerHashEntry *entry)
+{
+	bool found;
+	ListCell *lc;
+
+	foreach(lc, entry->tables)
+	{
+		MV_TriggerTable *table = (MV_TriggerTable *) lfirst(lc);
+
+		list_free(table->old_tuplestores);
+		list_free(table->new_tuplestores);
+	}
+	list_free(entry->tables);
+
+	hash_search(mv_trigger_info, (void *) &entry->matview_id, HASH_REMOVE, &found);
+}
+
+/*
+ * isIvmName
+ *
+ * Check if this is a IVM hidden column from the name.
+ */
+bool
+isIvmName(const char *s)
+{
+	if (s)
+		return (strncmp(s, "__ivm_", 6) == 0);
+	return false;
+}
+
+/*
+ * get_securityQuals
+ *
+ * Get row security policy on a relation.
+ * This is used by IVM for copying RLS from base table to enr.
+ */
+static List *
+get_securityQuals(Oid relId, int rt_index, Query *query)
+{
+	ParseState *pstate;
+	Relation rel;
+	ParseNamespaceItem *nsitem;
+	RangeTblEntry *rte;
+	List *securityQuals;
+	List *withCheckOptions;
+	bool  hasRowSecurity;
+	bool  hasSubLinks;
+
+	securityQuals = NIL;
+	pstate = make_parsestate(NULL);
+
+	rel = table_open(relId, NoLock);
+	nsitem = addRangeTableEntryForRelation(pstate, rel, AccessShareLock, NULL, false, false);
+	rte = nsitem->p_rte;
+
+	get_row_security_policies(query, rte, rt_index,
+							  &securityQuals, &withCheckOptions,
+							  &hasRowSecurity, &hasSubLinks);
+
+	/*
+	 * Make sure the query is marked correctly if row level security
+	 * applies, or if the new quals had sublinks.
+	 */
+	if (hasRowSecurity)
+		query->hasRowSecurity = true;
+	if (hasSubLinks)
+		query->hasSubLinks = true;
+
+	table_close(rel, NoLock);
+
+	return securityQuals;
+}
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 2cd8546d47..1c85df888e 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -52,6 +52,7 @@
 #include "commands/cluster.h"
 #include "commands/comment.h"
 #include "commands/defrem.h"
+#include "commands/matview.h"
 #include "commands/event_trigger.h"
 #include "commands/policy.h"
 #include "commands/sequence.h"
@@ -3441,6 +3442,14 @@ renameatt_internal(Oid myrelid,
 	targetrelation = relation_open(myrelid, AccessExclusiveLock);
 	renameatt_check(myrelid, RelationGetForm(targetrelation), recursing);
 
+	/*
+	 * Don't rename IVM columns.
+	 */
+	if (RelationIsIVM(targetrelation) && isIvmName(oldattname))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("IVM column can not be renamed")));
+
 	/*
 	 * if the 'recurse' flag is set then we are supposed to rename this
 	 * attribute in all classes that inherit from 'relname' (as well as in
diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c
index 0490bce664..4afc8f5826 100644
--- a/src/backend/nodes/copyfuncs.c
+++ b/src/backend/nodes/copyfuncs.c
@@ -2949,6 +2949,7 @@ _copyRangeTblEntry(const RangeTblEntry *from)
 	COPY_SCALAR_FIELD(relkind);
 	COPY_SCALAR_FIELD(rellockmode);
 	COPY_NODE_FIELD(tablesample);
+	COPY_SCALAR_FIELD(relisivm);
 	COPY_NODE_FIELD(subquery);
 	COPY_SCALAR_FIELD(security_barrier);
 	COPY_SCALAR_FIELD(jointype);
diff --git a/src/backend/nodes/equalfuncs.c b/src/backend/nodes/equalfuncs.c
index 55f41263ee..08d7805b7c 100644
--- a/src/backend/nodes/equalfuncs.c
+++ b/src/backend/nodes/equalfuncs.c
@@ -3131,6 +3131,7 @@ _equalRangeTblEntry(const RangeTblEntry *a, const RangeTblEntry *b)
 	COMPARE_SCALAR_FIELD(relkind);
 	COMPARE_SCALAR_FIELD(rellockmode);
 	COMPARE_NODE_FIELD(tablesample);
+	COMPARE_SCALAR_FIELD(relisivm);
 	COMPARE_NODE_FIELD(subquery);
 	COMPARE_SCALAR_FIELD(security_barrier);
 	COMPARE_SCALAR_FIELD(jointype);
diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
index cfd3ce68b4..e5a9467e99 100644
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@@ -3436,6 +3436,7 @@ _outRangeTblEntry(StringInfo str, const RangeTblEntry *node)
 			WRITE_CHAR_FIELD(relkind);
 			WRITE_INT_FIELD(rellockmode);
 			WRITE_NODE_FIELD(tablesample);
+			WRITE_BOOL_FIELD(relisivm);
 			break;
 		case RTE_SUBQUERY:
 			WRITE_NODE_FIELD(subquery);
diff --git a/src/backend/nodes/readfuncs.c b/src/backend/nodes/readfuncs.c
index 5165fb3b93..50cc852c32 100644
--- a/src/backend/nodes/readfuncs.c
+++ b/src/backend/nodes/readfuncs.c
@@ -1669,6 +1669,7 @@ _readRangeTblEntry(void)
 			READ_CHAR_FIELD(relkind);
 			READ_INT_FIELD(rellockmode);
 			READ_NODE_FIELD(tablesample);
+			READ_BOOL_FIELD(relisivm);
 			break;
 		case RTE_SUBQUERY:
 			READ_NODE_FIELD(subquery);
diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c
index 5448cb01fa..b08c742678 100644
--- a/src/backend/parser/parse_relation.c
+++ b/src/backend/parser/parse_relation.c
@@ -36,6 +36,7 @@
 #include "utils/rel.h"
 #include "utils/syscache.h"
 #include "utils/varlena.h"
+#include "commands/matview.h"

 /*
@@ -79,7 +80,7 @@ static void expandTupleDesc(TupleDesc tupdesc, Alias *eref,
 							int count, int offset,
 							int rtindex, int sublevels_up,
 							int location, bool include_dropped,
-							List **colnames, List **colvars);
+							List **colnames, List **colvars, bool is_ivm);
 static int	specialAttNum(const char *attname);
 static bool isQueryUsingTempRelation_walker(Node *node, void *context);
 
@@ -1444,6 +1445,7 @@ addRangeTableEntry(ParseState *pstate,
 	rte->relid = RelationGetRelid(rel);
 	rte->relkind = rel->rd_rel->relkind;
 	rte->rellockmode = lockmode;
+	rte->relisivm = rel->rd_rel->relisivm;
 
 	/*
 	 * Build the list of effective column names using user-supplied aliases
@@ -1532,6 +1534,7 @@ addRangeTableEntryForRelation(ParseState *pstate,
 	rte->relid = RelationGetRelid(rel);
 	rte->relkind = rel->rd_rel->relkind;
 	rte->rellockmode = lockmode;
+	rte->relisivm = rel->rd_rel->relisivm;
 
 	/*
 	 * Build the list of effective column names using user-supplied aliases
@@ -2688,7 +2691,7 @@ expandRTE(RangeTblEntry *rte, int rtindex, int sublevels_up,
 						expandTupleDesc(tupdesc, rte->eref,
 										rtfunc->funccolcount, atts_done,
 										rtindex, sublevels_up, location,
-										include_dropped, colnames, colvars);
+										include_dropped, colnames, colvars, false);
 					}
 					else if (functypclass == TYPEFUNC_SCALAR)
 					{
@@ -2956,7 +2959,7 @@ expandRelation(Oid relid, Alias *eref, int rtindex, int sublevels_up,
 	expandTupleDesc(rel->rd_att, eref, rel->rd_att->natts, 0,
 					rtindex, sublevels_up,
 					location, include_dropped,
-					colnames, colvars);
+					colnames, colvars, RelationIsIVM(rel));
 	relation_close(rel, AccessShareLock);
 }
 
@@ -2973,7 +2976,7 @@ static void
 expandTupleDesc(TupleDesc tupdesc, Alias *eref, int count, int offset,
 				int rtindex, int sublevels_up,
 				int location, bool include_dropped,
-				List **colnames, List **colvars)
+				List **colnames, List **colvars, bool is_ivm)
 {
 	ListCell   *aliascell;
 	int			varattno;
@@ -2986,6 +2989,9 @@ expandTupleDesc(TupleDesc tupdesc, Alias *eref, int count, int offset,
 	{
 		Form_pg_attribute attr = TupleDescAttr(tupdesc, varattno);
 
+		if (is_ivm && isIvmName(NameStr(attr->attname)) && !MatViewIncrementalMaintenanceIsEnabled())
+			continue;
+
 		if (attr->attisdropped)
 		{
 			if (include_dropped)
@@ -3140,6 +3146,10 @@ expandNSItemAttrs(ParseState *pstate, ParseNamespaceItem *nsitem,
 		Var		   *varnode = (Var *) lfirst(var);
 		TargetEntry *te;
 
+		/* if transform * into columnlist with IMMV, remove IVM columns */
+		if (rte->relisivm && isIvmName(label) && !MatViewIncrementalMaintenanceIsEnabled())
+			continue;
+
 		te = makeTargetEntry((Expr *) varnode,
 							 (AttrNumber) pstate->p_next_resno++,
 							 label,
diff --git a/src/backend/rewrite/rewriteDefine.c b/src/backend/rewrite/rewriteDefine.c
index 185bf5fbff..d8a8b66196 100644
--- a/src/backend/rewrite/rewriteDefine.c
+++ b/src/backend/rewrite/rewriteDefine.c
@@ -776,7 +776,8 @@ checkRuleResultList(List *targetList, TupleDesc resultDesc, bool isSelect,
 														attr->atttypmod))));
 	}
 
-	if (i != resultDesc->natts)
+	/* No check for materialized views since this could have special columns for IVM */
+	if ((!isSelect || requireColumnNameMatch) && i != resultDesc->natts)
 		ereport(ERROR,
 				(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
 				 isSelect ?
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 6d378ff785..7d88a84682 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -11882,4 +11882,12 @@
   prorettype => 'bytea', proargtypes => 'pg_brin_minmax_multi_summary',
   prosrc => 'brin_minmax_multi_summary_send' },
 
+# IVM
+{ oid => '786', descr => 'ivm trigger (before)',
+  proname => 'IVM_immediate_before', provolatile => 'v', prorettype => 'trigger',
+  proargtypes => '', prosrc => 'IVM_immediate_before' },
+{ oid => '787', descr => 'ivm trigger (after)',
+  proname => 'IVM_immediate_maintenance', provolatile => 'v', prorettype => 'trigger',
+  proargtypes => '', prosrc => 'IVM_immediate_maintenance' },
+
 ]
diff --git a/src/include/commands/createas.h b/src/include/commands/createas.h
index 54a38491fb..c369b3ba5e 100644
--- a/src/include/commands/createas.h
+++ b/src/include/commands/createas.h
@@ -16,6 +16,7 @@
 
 #include "catalog/objectaddress.h"
 #include "nodes/params.h"
+#include "nodes/pathnodes.h"
 #include "parser/parse_node.h"
 #include "tcop/dest.h"
 #include "utils/queryenvironment.h"
@@ -25,6 +26,11 @@ extern ObjectAddress ExecCreateTableAs(ParseState *pstate, CreateTableAsStmt *st
 									   ParamListInfo params, QueryEnvironment *queryEnv,
 									   QueryCompletion *qc);
 
+extern void CreateIvmTriggersOnBaseTables(Query *qry, Oid matviewOid, bool is_create);
+extern void CreateIndexOnIMMV(Query *query, Relation matviewRel, bool is_create);
+
+extern Query *rewriteQueryForIMMV(Query *query, List *colNames);
+
 extern int	GetIntoRelEFlags(IntoClause *intoClause);
 
 extern DestReceiver *CreateIntoRelDestReceiver(IntoClause *intoClause);
diff --git a/src/include/commands/matview.h b/src/include/commands/matview.h
index a067da39d2..ec479db513 100644
--- a/src/include/commands/matview.h
+++ b/src/include/commands/matview.h
@@ -15,6 +15,7 @@
 #define MATVIEW_H
 
 #include "catalog/objectaddress.h"
+#include "fmgr.h"
 #include "nodes/params.h"
 #include "nodes/parsenodes.h"
 #include "tcop/dest.h"
@@ -23,6 +24,8 @@
 
 extern void SetMatViewPopulatedState(Relation relation, bool newstate);
 
+extern void SetMatViewIVMState(Relation relation, bool newstate);
+
 extern ObjectAddress ExecRefreshMatView(RefreshMatViewStmt *stmt, const char *queryString,
 										ParamListInfo params, QueryCompletion *qc);
 
@@ -30,4 +33,9 @@ extern DestReceiver *CreateTransientRelDestReceiver(Oid oid);
 
 extern bool MatViewIncrementalMaintenanceIsEnabled(void);
 
+extern Datum IVM_immediate_before(PG_FUNCTION_ARGS);
+extern Datum IVM_immediate_maintenance(PG_FUNCTION_ARGS);
+extern void AtAbort_IVM(void);
+extern bool isIvmName(const char *s);
+
 #endif							/* MATVIEW_H */
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index da02658c81..d1a754936b 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -1042,6 +1042,7 @@ typedef struct RangeTblEntry
 	char		relkind;		/* relation kind (see pg_class.relkind) */
 	int			rellockmode;	/* lock level that query requires on the rel */
 	struct TableSampleClause *tablesample;	/* sampling info, or NULL */
+	bool		relisivm;
 
 	/*
 	 * Fields valid for a subquery RTE (else NULL):
@@ -2545,6 +2546,7 @@ typedef struct CreateStmt
 	char	   *tablespacename; /* table space to use, or NULL */
 	char	   *accessMethod;	/* table access method */
 	bool		if_not_exists;	/* just do nothing if it already exists? */
+	bool		ivm;			/* incremental view maintenance is used by materialized view */
 } CreateStmt;
 
 /* ----------
-- 
2.17.1

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