Fix incremental backup interaction with XLOG_DBASE_CREATE_FILE_COPY.

After XLOG_DBASE_CREATE_FILE_COPY, a correct incremental backup needs
to copy in full everything with the database and tablespace OID
mentioned in that record; but that record doesn't specifically mention
the blocks, or even the relfilenumbers, of the affected relations.
As a result, we were failing to copy data that we should have copied.

To fix, enter the DB OID and tablespace OID into the block reference
table with relfilenumber 0 and limit block 0; and treat that as a
limit block of 0 for every relfilenumber whose DB OID and tablespace
OID match.

Also, add a test case.

Patch by me, reviewed by Noah Misch.

Discussion: http://postgr.es/m/CA+Tgmob0xa=ByvGLMdAgkUZyVQE=r4nyYZ_VEa40FCfEDFnTKA@mail.gmail.com

1 files changed, 17 insertions, 1 deletions

diff --git a/src/backend/backup/basebackup_incremental.c b/src/backend/backup/basebackup_incremental.c
index 18c78adda26..a8f2e72e7b1 100644
--- a/src/backend/backup/basebackup_incremental.c
+++ b/src/backend/backup/basebackup_incremental.c
@@ -777,9 +777,25 @@ GetFileBackupMethod(IncrementalBackupInfo *ib, const char *path,
 			return BACK_UP_FILE_FULLY;
 	}
 
-	/* Look up the block reference table entry. */
+	/*
+	 * Look up the special block reference table entry for the database as
+	 * a whole.
+	 */
 	rlocator.spcOid = spcoid;
 	rlocator.dbOid = dboid;
+	rlocator.relNumber = 0;
+	if (BlockRefTableGetEntry(ib->brtab, &rlocator, MAIN_FORKNUM,
+							  &limit_block) != NULL)
+	{
+		/*
+		 * According to the WAL summary, this database OID/tablespace OID
+		 * pairing has been created since the previous backup. So, everything
+		 * in it must be backed up fully.
+		 */
+		return BACK_UP_FILE_FULLY;
+	}
+
+	/* Look up the block reference table entry for this relfilenode. */
 	rlocator.relNumber = relfilenumber;
 	brtentry = BlockRefTableGetEntry(ib->brtab, &rlocator, forknum,
 									 &limit_block);