Fix pg_dump's heuristic for deciding which casts to dump.

tglsfdc · tglsfdc · commit 8e70f3c40a0a · 2015-02-10T22:38:29.000-05:00
Back in 2003 we had a discussion about how to decide which casts to dump. At the time pg_dump really only considered an object's containing schema to decide what to dump (ie, dump whatever's not in pg_catalog), and so we chose a complicated idea involving whether the underlying types were to be dumped (cf commit a6790ce). But users are allowed to create casts between built-in types, and we failed to dump such casts. Let's get rid of that heuristic, which has accreted even more ugliness since then, in favor of just looking at the cast's OID to decide if it's a built-in cast or not. In passing, also fix some really ancient code that supposed that it had to manufacture a dependency for the cast on its cast function; that's only true when dumping from a pre-7.3 server. This just resulted in some wasted cycles and duplicate dependency-list entries with newer servers, but we might as well improve it. Per gripes from a number of people, most recently Greg Sabino Mullane. Back-patch to all supported branches.
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
@@ -45,6 +45,7 @@
 
 #include "access/attnum.h"
 #include "access/sysattr.h"
+#include "access/transam.h"
 #include "catalog/pg_cast.h"
 #include "catalog/pg_class.h"
 #include "catalog/pg_default_acl.h"
@@ -1081,6 +1082,24 @@ selectDumpableDefaultACL(DefaultACLInfo *dinfo)
 		dinfo->dobj.dump = include_everything;
 }
 
+/*
+ * selectDumpableCast: policy-setting subroutine
+ *		Mark a cast as to be dumped or not
+ *
+ * Casts do not belong to any particular namespace (since they haven't got
+ * names), nor do they have identifiable owners.  To distinguish user-defined
+ * casts from built-in ones, we must resort to checking whether the cast's
+ * OID is in the range reserved for initdb.
+ */
+static void
+selectDumpableCast(CastInfo *cast)
+{
+	if (cast->dobj.catId.oid < (Oid) FirstNormalObjectId)
+		cast->dobj.dump = false;
+	else
+		cast->dobj.dump = include_everything;
+}
+
 /*
  * selectDumpableObject: policy-setting subroutine
  *		Mark a generic dumpable object as to be dumped or not
@@ -5071,12 +5090,13 @@ getCasts(int *numCasts)
 							  sTypeInfo->dobj.name, tTypeInfo->dobj.name);
 		castinfo[i].dobj.name = namebuf.data;
 
-		if (OidIsValid(castinfo[i].castfunc))
+		if (g_fout->remoteVersion < 70300 &&
+			OidIsValid(castinfo[i].castfunc))
 		{
 			/*
 			 * We need to make a dependency to ensure the function will be
 			 * dumped first.  (In 7.3 and later the regular dependency
-			 * mechanism will handle this for us.)
+			 * mechanism handles this for us.)
 			 */
 			FuncInfo   *funcInfo;
 
@@ -5085,6 +5105,9 @@ getCasts(int *numCasts)
 				addObjectDependency(&castinfo[i].dobj,
 									funcInfo->dobj.dumpId);
 		}
+
+		/* Decide whether we want to dump it */
+		selectDumpableCast(&(castinfo[i]));
 	}
 
 	PQclear(res);
@@ -8308,12 +8331,12 @@ dumpCast(Archive *fout, CastInfo *cast)
 	PQExpBuffer delqry;
 	PQExpBuffer castsig;
 	FuncInfo   *funcInfo = NULL;
-	TypeInfo   *sourceInfo;
-	TypeInfo   *targetInfo;
 
-	if (dataOnly)
+	/* Skip if not to be dumped */
+	if (!cast->dobj.dump || dataOnly)
 		return;
 
+	/* Cannot dump if we don't have the cast function's info */
 	if (OidIsValid(cast->castfunc))
 	{
 		funcInfo = findFuncByOid(cast->castfunc);
@@ -8322,49 +8345,9 @@ dumpCast(Archive *fout, CastInfo *cast)
 	}
 
 	/*
-	 * As per discussion we dump casts if one or more of the underlying
-	 * objects (the conversion function and the two data types) are not
-	 * builtin AND if all of the non-builtin objects are included in the dump.
-	 * Builtin meaning, the namespace name does not start with "pg_".
-	 */
-	sourceInfo = findTypeByOid(cast->castsource);
-	targetInfo = findTypeByOid(cast->casttarget);
-
-	if (sourceInfo == NULL || targetInfo == NULL)
-		return;
-
-	/*
-	 * Skip this cast if all objects are from pg_
-	 */
-	if ((funcInfo == NULL ||
-		 strncmp(funcInfo->dobj.namespace->dobj.name, "pg_", 3) == 0) &&
-		strncmp(sourceInfo->dobj.namespace->dobj.name, "pg_", 3) == 0 &&
-		strncmp(targetInfo->dobj.namespace->dobj.name, "pg_", 3) == 0)
-		return;
-
-	/*
-	 * Skip cast if function isn't from pg_ and is not to be dumped.
-	 */
-	if (funcInfo &&
-		strncmp(funcInfo->dobj.namespace->dobj.name, "pg_", 3) != 0 &&
-		!funcInfo->dobj.dump)
-		return;
-
-	/*
-	 * Same for the source type
-	 */
-	if (strncmp(sourceInfo->dobj.namespace->dobj.name, "pg_", 3) != 0 &&
-		!sourceInfo->dobj.dump)
-		return;
-
-	/*
-	 * and the target type.
+	 * Make sure we are in proper schema (needed for getFormattedTypeName).
+	 * Casts don't have a schema of their own, so use pg_catalog.
 	 */
-	if (strncmp(targetInfo->dobj.namespace->dobj.name, "pg_", 3) != 0 &&
-		!targetInfo->dobj.dump)
-		return;
-
-	/* Make sure we are in proper schema (needed for getFormattedTypeName) */
 	selectSourceSchema("pg_catalog");
 
 	defqry = createPQExpBuffer();
