Add support for TG_DEPTH to PL/pgSQL trigger functions.

7 files changed, 32 insertions, 1 deletions

diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index 1e31e07ec9..ddfbd3a1fd 100644
--- a/src/backend/access/transam/xact.c
+++ b/src/backend/access/transam/xact.c
@@ -142,6 +142,7 @@ typedef struct TransactionStateData
 	Oid			prevUser;		/* previous CurrentUserId setting */
 	int			prevSecContext; /* previous SecurityRestrictionContext */
 	bool		prevXactReadOnly;		/* entry-time xact r/o state */
+	int			prevTgDepth;	/* previous trigger depth */
 	bool		startedInRecovery;		/* did we start in recovery? */
 	struct TransactionStateData *parent;		/* back link to parent */
 } TransactionStateData;
@@ -171,6 +172,7 @@ static TransactionStateData TopTransactionStateData = {
 	InvalidOid,					/* previous CurrentUserId setting */
 	0,							/* previous SecurityRestrictionContext */
 	false,						/* entry-time xact r/o state */
+	0,							/* previous trigger depth */
 	false,						/* startedInRecovery */
 	NULL						/* link to parent state block */
 };
@@ -3996,6 +3998,8 @@ CommitSubTransaction(void)
 	 */
 	XactReadOnly = s->prevXactReadOnly;
 
+	tg_depth = s->prevTgDepth;
+
 	CurrentResourceOwner = s->parent->curTransactionOwner;
 	CurTransactionResourceOwner = s->parent->curTransactionOwner;
 	ResourceOwnerDelete(s->curTransactionOwner);
@@ -4114,6 +4118,8 @@ AbortSubTransaction(void)
 	 */
 	XactReadOnly = s->prevXactReadOnly;
 
+	tg_depth = s->prevTgDepth;
+
 	RESUME_INTERRUPTS();
 }
 
@@ -4196,6 +4202,7 @@ PushTransaction(void)
 	s->blockState = TBLOCK_SUBBEGIN;
 	GetUserIdAndSecContext(&s->prevUser, &s->prevSecContext);
 	s->prevXactReadOnly = XactReadOnly;
+	s->prevTgDepth = tg_depth;
 
 	CurrentTransactionState = s;
 
diff --git a/src/backend/commands/trigger.c b/src/backend/commands/trigger.c
index 48021388fc..056b656fc2 100644
--- a/src/backend/commands/trigger.c
+++ b/src/backend/commands/trigger.c
@@ -55,10 +55,12 @@
 #include "utils/tqual.h"
 
 
+/* How many levels deep into trigger execution are we? */
+int	tg_depth = 0;
+
 /* GUC variables */
 int			SessionReplicationRole = SESSION_REPLICATION_ROLE_ORIGIN;
 
-
 #define GetModifiedColumns(relinfo, estate) \
 	(rt_fetch((relinfo)->ri_RangeTableIndex, (estate)->es_range_table)->modifiedCols)
 
@@ -1807,6 +1809,8 @@ ExecCallTriggerFunc(TriggerData *trigdata,
 	if (instr)
 		InstrStartNode(instr + tgindx);
 
+	tg_depth++;
+
 	/*
 	 * Do the function evaluation in the per-tuple memory context, so that
 	 * leaked memory will be reclaimed once per tuple. Note in particular that
@@ -1828,6 +1832,8 @@ ExecCallTriggerFunc(TriggerData *trigdata,
 
 	MemoryContextSwitchTo(oldContext);
 
+	tg_depth--;
+
 	/*
 	 * Trigger protocol allows function to return a null pointer, but NOT to
 	 * set the isnull result flag.
diff --git a/src/backend/tcop/pquery.c b/src/backend/tcop/pquery.c
index 0b108ac134..5b67346388 100644
--- a/src/backend/tcop/pquery.c
+++ b/src/backend/tcop/pquery.c
@@ -748,6 +748,8 @@ PortalRun(Portal portal, long count, bool isTopLevel,
 				 errmsg("portal \"%s\" cannot be run", portal->name)));
 	portal->status = PORTAL_ACTIVE;
 
+	tg_depth = 0;
+
 	/*
 	 * Set up global portal context pointers.
 	 *
@@ -1371,6 +1373,8 @@ PortalRunFetch(Portal portal,
 				 errmsg("portal \"%s\" cannot be run", portal->name)));
 	portal->status = PORTAL_ACTIVE;
 
+	tg_depth = 0;
+
 	/*
 	 * Set up global portal context pointers.
 	 */
diff --git a/src/include/commands/trigger.h b/src/include/commands/trigger.h
index c213ac7a4e..90a3ea7a61 100644
--- a/src/include/commands/trigger.h
+++ b/src/include/commands/trigger.h
@@ -108,6 +108,8 @@ extern PGDLLIMPORT int SessionReplicationRole;
 #define TRIGGER_FIRES_ON_REPLICA			'R'
 #define TRIGGER_DISABLED					'D'
 
+extern int	tg_depth;
+
 extern Oid CreateTrigger(CreateTrigStmt *stmt, const char *queryString,
 			  Oid constraintOid, Oid indexOid,
 			  bool isInternal);
diff --git a/src/pl/plpgsql/src/pl_comp.c b/src/pl/plpgsql/src/pl_comp.c
index 41188a2369..175ad7ab85 100644
--- a/src/pl/plpgsql/src/pl_comp.c
+++ b/src/pl/plpgsql/src/pl_comp.c
@@ -633,6 +633,12 @@ do_compile(FunctionCallInfo fcinfo,
 										 true);
 			function->tg_table_schema_varno = var->dno;
 
+			/* add the variable tg_depth */
+			var = plpgsql_build_variable("tg_depth", 0,
+										 plpgsql_build_datatype(INT4OID, -1),
+										 true);
+			function->tg_depth_varno = var->dno;
+
 			/* Add the variable tg_nargs */
 			var = plpgsql_build_variable("tg_nargs", 0,
 										 plpgsql_build_datatype(INT4OID, -1),
diff --git a/src/pl/plpgsql/src/pl_exec.c b/src/pl/plpgsql/src/pl_exec.c
index 3e40945e35..82b73a0490 100644
--- a/src/pl/plpgsql/src/pl_exec.c
+++ b/src/pl/plpgsql/src/pl_exec.c
@@ -625,6 +625,11 @@ plpgsql_exec_trigger(PLpgSQL_function *func,
 	var->isnull = false;
 	var->freeval = true;
 
+	var = (PLpgSQL_var *) (estate.datums[func->tg_depth_varno]);
+	var->value = Int16GetDatum(tg_depth);
+	var->isnull = false;
+	var->freeval = false;
+
 	var = (PLpgSQL_var *) (estate.datums[func->tg_nargs_varno]);
 	var->value = Int16GetDatum(trigdata->tg_trigger->tgnargs);
 	var->isnull = false;
diff --git a/src/pl/plpgsql/src/plpgsql.h b/src/pl/plpgsql/src/plpgsql.h
index 0ad7e28136..2165526957 100644
--- a/src/pl/plpgsql/src/plpgsql.h
+++ b/src/pl/plpgsql/src/plpgsql.h
@@ -668,6 +668,7 @@ typedef struct PLpgSQL_function
 	int			tg_relname_varno;
 	int			tg_table_name_varno;
 	int			tg_table_schema_varno;
+	int			tg_depth_varno;
 	int			tg_nargs_varno;
 	int			tg_argv_varno;