Fix pg_restore to do the right thing when escaping large objects.

Specifically, this makes the workflow pg_dump -Fc -> pg_restore -> file
produce correct output for BLOBs when the source database has
standard_conforming_strings turned on.  It was already okay when that was
off, or if pg_restore was told to restore directly into a database.

This is a back-port of commit b1732111f233bbb72788e92a627242ec28a85631 of
2009-08-04, with additional changes to emit old-style escaped bytea data
instead of hex-style.  At the time, we had not heard of anyone encountering
the problem in the field, so I judged it not worth the risk of changing
back branches.  Now we do have a report, from Bosco Rama, so back-patch
into 8.2 through 8.4.  9.0 and up are okay already.

1 files changed, 8 insertions, 7 deletions

diff --git a/src/bin/pg_dump/pg_backup_null.c b/src/bin/pg_dump/pg_backup_null.c
index f31a173ce1f..84bbf3ac6b3 100644
--- a/src/bin/pg_dump/pg_backup_null.c
+++ b/src/bin/pg_dump/pg_backup_null.c
@@ -23,6 +23,7 @@
  */
 
 #include "pg_backup_archiver.h"
+#include "dumputils.h"
 
 #include <unistd.h>				/* for dup */
 
@@ -98,16 +99,16 @@ _WriteBlobData(ArchiveHandle *AH, const void *data, size_t dLen)
 {
 	if (dLen > 0)
 	{
-		unsigned char *str;
-		size_t		len;
+		PQExpBuffer buf = createPQExpBuffer();
 
-		str = PQescapeBytea((const unsigned char *) data, dLen, &len);
-		if (!str)
-			die_horribly(AH, NULL, "out of memory\n");
+		appendByteaLiteralAHX(buf,
+							  (const unsigned char *) data,
+							  dLen,
+							  AH);
 
-		ahprintf(AH, "SELECT lowrite(0, '%s');\n", str);
+		ahprintf(AH, "SELECT pg_catalog.lowrite(0, %s);\n", buf->data);
 
-		free(str);
+		destroyPQExpBuffer(buf);
 	}
 	return dLen;
 }