Implement syntax for transition tables in AFTER triggers.

This is infrastructure for the complete SQL standard feature.  No
support is included at this point for execution nodes or PLs.  The
intent is to add that soon.

As this patch leaves things, standard syntax can create tuplestores
to contain old and/or new versions of rows affected by a statement.
References to these tuplestores are in the TriggerData structure.
C triggers can access the tuplestores directly, so they are usable,
but they cannot yet be referenced within a SQL statement.

3 files changed, 43 insertions, 0 deletions

diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c
index 71714bc1d67..04e49b77951 100644
--- a/src/backend/nodes/copyfuncs.c
+++ b/src/backend/nodes/copyfuncs.c
@@ -2718,6 +2718,18 @@ _copyRoleSpec(const RoleSpec *from)
 	return newnode;
 }
 
+static TriggerTransition *
+_copyTriggerTransition(const TriggerTransition *from)
+{
+	TriggerTransition *newnode = makeNode(TriggerTransition);
+
+	COPY_STRING_FIELD(name);
+	COPY_SCALAR_FIELD(isNew);
+	COPY_SCALAR_FIELD(isTable);
+
+	return newnode;
+}
+
 static Query *
 _copyQuery(const Query *from)
 {
@@ -3893,6 +3905,7 @@ _copyCreateTrigStmt(const CreateTrigStmt *from)
 	COPY_NODE_FIELD(columns);
 	COPY_NODE_FIELD(whenClause);
 	COPY_SCALAR_FIELD(isconstraint);
+	COPY_NODE_FIELD(transitionRels);
 	COPY_SCALAR_FIELD(deferrable);
 	COPY_SCALAR_FIELD(initdeferred);
 	COPY_NODE_FIELD(constrrel);
@@ -5088,6 +5101,9 @@ copyObject(const void *from)
 		case T_RoleSpec:
 			retval = _copyRoleSpec(from);
 			break;
+		case T_TriggerTransition:
+			retval = _copyTriggerTransition(from);
+			break;
 
 			/*
 			 * MISCELLANEOUS NODES
diff --git a/src/backend/nodes/equalfuncs.c b/src/backend/nodes/equalfuncs.c
index 29a090fc48b..2eaf41c37f8 100644
--- a/src/backend/nodes/equalfuncs.c
+++ b/src/backend/nodes/equalfuncs.c
@@ -1905,6 +1905,7 @@ _equalCreateTrigStmt(const CreateTrigStmt *a, const CreateTrigStmt *b)
 	COMPARE_NODE_FIELD(columns);
 	COMPARE_NODE_FIELD(whenClause);
 	COMPARE_SCALAR_FIELD(isconstraint);
+	COMPARE_NODE_FIELD(transitionRels);
 	COMPARE_SCALAR_FIELD(deferrable);
 	COMPARE_SCALAR_FIELD(initdeferred);
 	COMPARE_NODE_FIELD(constrrel);
@@ -2634,6 +2635,16 @@ _equalRoleSpec(const RoleSpec *a, const RoleSpec *b)
 	return true;
 }
 
+static bool
+_equalTriggerTransition(const TriggerTransition *a, const TriggerTransition *b)
+{
+	COMPARE_STRING_FIELD(name);
+	COMPARE_SCALAR_FIELD(isNew);
+	COMPARE_SCALAR_FIELD(isTable);
+
+	return true;
+}
+
 /*
  * Stuff from pg_list.h
  */
@@ -3387,6 +3398,9 @@ equal(const void *a, const void *b)
 		case T_RoleSpec:
 			retval = _equalRoleSpec(a, b);
 			break;
+		case T_TriggerTransition:
+			retval = _equalTriggerTransition(a, b);
+			break;
 
 		default:
 			elog(ERROR, "unrecognized node type: %d",
diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
index ae869547f35..748b6879292 100644
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@@ -2562,6 +2562,16 @@ _outXmlSerialize(StringInfo str, const XmlSerialize *node)
 }
 
 static void
+_outTriggerTransition(StringInfo str, const TriggerTransition *node)
+{
+	WRITE_NODE_TYPE("TRIGGERTRANSITION");
+
+	WRITE_STRING_FIELD(name);
+	WRITE_BOOL_FIELD(isNew);
+	WRITE_BOOL_FIELD(isTable);
+}
+
+static void
 _outColumnDef(StringInfo str, const ColumnDef *node)
 {
 	WRITE_NODE_TYPE("COLUMNDEF");
@@ -3852,6 +3862,9 @@ outNode(StringInfo str, const void *obj)
 			case T_ForeignKeyCacheInfo:
 				_outForeignKeyCacheInfo(str, obj);
 				break;
+			case T_TriggerTransition:
+				_outTriggerTransition(str, obj);
+				break;
 
 			default: