fix: clear DBMS_OUTPUT buffer on DISCARD ALL/PACKAGES

rophy · rophy · commit b2480af010a9 · 2026-01-06T14:00:27.000Z
Use ProcessUtility_hook to intercept DISCARD ALL/PACKAGES commands
and reset DBMS_OUTPUT buffer state. This prevents session state
leakage in connection pooling environments like PgBouncer.

All changes confined to contrib/ivorysql_ora - no backend modifications.
diff --git a/contrib/ivorysql_ora/src/builtin_packages/dbms_output/dbms_output.c b/contrib/ivorysql_ora/src/builtin_packages/dbms_output/dbms_output.c
@@ -625,3 +625,17 @@ ora_dbms_output_get_lines(PG_FUNCTION_ARGS)
 	tuple = heap_form_tuple(tupdesc, values, nulls);
 	PG_RETURN_DATUM(HeapTupleGetDatum(tuple));
 }
+
+/*
+ * ora_dbms_output_reset
+ *
+ * Reset DBMS_OUTPUT buffer state. Called by DISCARD ALL/PACKAGES
+ * to ensure session state is properly cleared, which is important
+ * for connection pooling environments (e.g., PgBouncer).
+ */
+void
+ora_dbms_output_reset(void)
+{
+	if (output_buffer != NULL)
+		cleanup_output_buffer();
+}
diff --git a/contrib/ivorysql_ora/src/ivorysql_ora.c b/contrib/ivorysql_ora/src/ivorysql_ora.c
@@ -31,8 +31,10 @@
 #include "access/heapam.h"
 #include "fmgr.h"
 #include "miscadmin.h"
+#include "nodes/parsenodes.h"
 #include "parser/parse_oper.h"
 #include "parser/parse_merge.h"
+#include "tcop/utility.h"
 
 /* Begin - ReqID:SRS-SQL-XML */
 #include "executor/execExpr.h"
@@ -41,6 +43,9 @@
 #include "include/guc.h"
 #include "include/ivorysql_ora.h"
 
+/* DBMS_OUTPUT reset function from builtin_packages/dbms_output/dbms_output.c */
+extern void ora_dbms_output_reset(void);
+
 
 /* Only include it once in any C file */
 PG_MODULE_MAGIC_EXT(
@@ -60,6 +65,19 @@ static transform_merge_stmt_hook_type pre_transform_merge_stmt_hook = NULL;
 static ora_updatexml_hook_type pre_ora_updatexml_hook = NULL;
 /* End - ReqID:SRS-SQL-XML */
 
+/* ProcessUtility hook for DISCARD ALL/PACKAGES handling */
+static ProcessUtility_hook_type prev_ProcessUtility_hook = NULL;
+
+/* Forward declaration */
+static void ivorysql_ora_ProcessUtility(PlannedStmt *pstmt,
+										const char *queryString,
+										bool readOnlyTree,
+										ProcessUtilityContext context,
+										ParamListInfo params,
+										QueryEnvironment *queryEnv,
+										DestReceiver *dest,
+										QueryCompletion *qc);
+
 void _PG_init(void);
 void _PG_fini(void);
 
@@ -95,6 +113,10 @@ _PG_init(void)
 	pre_ora_updatexml_hook = ora_updatexml_hook;
 	ora_updatexml_hook = updatexml;
 	/* End - ReqID:SRS-SQL-XML */
+
+	/* ProcessUtility hook for DISCARD ALL/PACKAGES */
+	prev_ProcessUtility_hook = ProcessUtility_hook;
+	ProcessUtility_hook = ivorysql_ora_ProcessUtility;
 }
 
 /*
@@ -116,4 +138,46 @@ _PG_fini(void)
 	/* Begin - ReqID:SRS-SQL-XML */
 	ora_updatexml_hook = pre_ora_updatexml_hook;
 	/* End - ReqID:SRS-SQL-XML */
+
+	/* ProcessUtility hook */
+	ProcessUtility_hook = prev_ProcessUtility_hook;
+}
+
+/*
+ * ProcessUtility hook to intercept DISCARD ALL/PACKAGES commands.
+ * Resets DBMS_OUTPUT buffer state after these commands execute.
+ */
+static void
+ivorysql_ora_ProcessUtility(PlannedStmt *pstmt,
+							const char *queryString,
+							bool readOnlyTree,
+							ProcessUtilityContext context,
+							ParamListInfo params,
+							QueryEnvironment *queryEnv,
+							DestReceiver *dest,
+							QueryCompletion *qc)
+{
+	Node	   *parsetree = pstmt->utilityStmt;
+	bool		is_discard_reset = false;
+
+	/* Check if this is DISCARD ALL or DISCARD PACKAGES */
+	if (nodeTag(parsetree) == T_DiscardStmt)
+	{
+		DiscardStmt *stmt = (DiscardStmt *) parsetree;
+
+		if (stmt->target == DISCARD_ALL || stmt->target == DISCARD_PACKAGES)
+			is_discard_reset = true;
+	}
+
+	/* Call the previous hook or standard function */
+	if (prev_ProcessUtility_hook)
+		(*prev_ProcessUtility_hook)(pstmt, queryString, readOnlyTree,
+									context, params, queryEnv, dest, qc);
+	else
+		standard_ProcessUtility(pstmt, queryString, readOnlyTree,
+								context, params, queryEnv, dest, qc);
+
+	/* Reset DBMS_OUTPUT buffer after DISCARD ALL/PACKAGES */
+	if (is_discard_reset)
+		ora_dbms_output_reset();
 }
