Forward-port our hacked tupconvert.c to PostgreSQL 14

df7cb · Nov 16, 2021 · 446e2c5 · 446e2c5
1 parent ee0377d
commit 446e2c5
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Showing 3 changed files with 32 additions and 4 deletions.
diff --git a/dirtyread_tupconvert.c b/dirtyread_tupconvert.c
@@ -1,4 +1,8 @@
 /*-------------------------------------------------------------------------
+ *
+ * Copy of PostgreSQL 11's tupconvert.c for use by pg_dirtyread. The difference
+ * is added support for system columns like xmin/xmax/oid. PostgreSQL 14
+ * refactored it a lot, but the PG 11 version still works, so we stick with it.
  *
  * tupconvert.c
  *	  Tuple conversion support.
@@ -145,7 +149,14 @@ dirtyread_convert_tuples_by_name(TupleDesc indesc,
 	map = (TupleConversionMap *) palloc(sizeof(TupleConversionMap));
 	map->indesc = indesc;
 	map->outdesc = outdesc;
+#if PG_VERSION_NUM >= 140000
+	/* TupleConversionMap->attrMap changed in PG14; luckily our old data structure is just a member of that */
+	map->attrMap = (AttrMap *) palloc(sizeof(AttrMap));
+	map->attrMap->attnums = attrMap;
+	map->attrMap->maplen = n;
+#else
 	map->attrMap = attrMap;
+#endif
 	/* preallocate workspace for Datum arrays */
 	map->outvalues = (Datum *) palloc(n * sizeof(Datum));
 	map->outisnull = (bool *) palloc(n * sizeof(bool));
@@ -321,9 +332,14 @@ dirtyread_convert_tuples_by_name_map(TupleDesc indesc,
  * Perform conversion of a tuple according to the map.
  */
 HeapTuple
-dirtyread_do_convert_tuple(HeapTuple tuple, TupleConversionMap *map, TransactionId oldest_xmin)
+dirtyread_do_convert_tuple(HeapTuple tuple, TupleConversionMap *map, OldestXminType oldest_xmin)
 {
-	AttrNumber *attrMap = map->attrMap;
+	AttrNumber *attrMap =
+#if PG_VERSION_NUM >= 140000
+		map->attrMap->attnums;
+#else
+		map->attrMap;
+#endif
 	Datum	   *invalues = map->invalues;
 	bool	   *inisnull = map->inisnull;
 	Datum	   *outvalues = map->outvalues;

diff --git a/dirtyread_tupconvert.h b/dirtyread_tupconvert.h
@@ -15,6 +15,13 @@
 #define DIRTYREAD_TUPCONVERT_H
 
 #include "access/tupconvert.h"
+#include "utils/snapmgr.h"
+
+#if PG_VERSION_NUM >= 140000
+#define OldestXminType GlobalVisState *
+#else
+#define OldestXminType TransactionId
+#endif
 
 extern TupleConversionMap *dirtyread_convert_tuples_by_name(TupleDesc indesc,
 					   TupleDesc outdesc,
@@ -24,7 +31,7 @@ extern AttrNumber *dirtyread_convert_tuples_by_name_map(TupleDesc indesc,
 						   TupleDesc outdesc,
 						   const char *msg);
 
-extern HeapTuple dirtyread_do_convert_tuple(HeapTuple tuple, TupleConversionMap *map, TransactionId oldest_xmin);
+extern HeapTuple dirtyread_do_convert_tuple(HeapTuple tuple, TupleConversionMap *map, OldestXminType oldest_xmin);
 
 #define DeadFakeAttributeNumber FirstLowInvalidHeapAttributeNumber
 

diff --git a/pg_dirtyread.c b/pg_dirtyread.c
@@ -64,7 +64,7 @@ typedef struct
 #else
     HeapScanDesc        scan;
 #endif
-    TransactionId       oldest_xmin;
+    OldestXminType      oldest_xmin;
 } pg_dirtyread_ctx;
 
 PG_MODULE_MAGIC;
@@ -117,6 +117,10 @@ pg_dirtyread(PG_FUNCTION_ARGS)
                 , NULL, 0
 #endif
                 );
+
+#if PG_VERSION_NUM >= 140000
+        usr_ctx->oldest_xmin = GlobalVisTestFor(usr_ctx->rel);
+#else
         /* only call GetOldestXmin while not in recovery */
         if (!RecoveryInProgress())
             usr_ctx->oldest_xmin = GetOldestXmin(
@@ -126,6 +130,7 @@ pg_dirtyread(PG_FUNCTION_ARGS)
                 false /* allDbs */
 #endif
                 , 0);
+#endif
         funcctx->user_fctx = (void *) usr_ctx;
         MemoryContextSwitchTo(oldcontext);
     }