Deduplicate code in LargeObjectExists and myLargeObjectExists.

myLargeObjectExists() and LargeObjectExists() had nearly identical code,
except for handling snapshots. This commit renames myLargeObjectExists()
to LargeObjectExistsWithSnapshot() and refactors LargeObjectExists()
to call it internally, reducing duplication.

Author: Yugo Nagata
Reviewed-by: Fujii Masao
Discussion: https://postgr.es/m/20240702163444.ab586f6075e502eb84f11b1a@sranhm.sraoss.co.jp

diff --git a/src/backend/catalog/pg_largeobject.c b/src/backend/catalog/pg_largeobject.c
index e235f7c5e680ee8df7e12b7fefb70471b109bb81..5d9fdfbd4cd7bfd7ee3a1c68c572d96ecadb4450 100644 (file)
--- a/src/backend/catalog/pg_largeobject.c
+++ b/src/backend/catalog/pg_largeobject.c
@@ -14,8 +14,6 @@
  */
 #include "postgres.h"
 
-#include "access/genam.h"
-#include "access/htup_details.h"
 #include "access/table.h"
 #include "catalog/catalog.h"
 #include "catalog/indexing.h"
@@ -153,6 +151,15 @@ LargeObjectDrop(Oid loid)
  */
 bool
 LargeObjectExists(Oid loid)
+{
+   return LargeObjectExistsWithSnapshot(loid, NULL);
+}
+
+/*
+ * Same as LargeObjectExists(), except snapshot to read with can be specified.
+ */
+bool
+LargeObjectExistsWithSnapshot(Oid loid, Snapshot snapshot)
 {
    Relation    pg_lo_meta;
    ScanKeyData skey[1];
@@ -170,7 +177,7 @@ LargeObjectExists(Oid loid)
 
    sd = systable_beginscan(pg_lo_meta,
                            LargeObjectMetadataOidIndexId, true,
-                           NULL, 1, skey);
+                           snapshot, 1, skey);
 
    tuple = systable_getnext(sd);
    if (HeapTupleIsValid(tuple))

diff --git a/src/backend/storage/large_object/inv_api.c b/src/backend/storage/large_object/inv_api.c
index f9510833241bbdff80190c04d0f835edeeb807ea..afce51c167472dd93f9c06f87c3ed9a78280e88d 100644 (file)
--- a/src/backend/storage/large_object/inv_api.c
+++ b/src/backend/storage/large_object/inv_api.c
@@ -41,7 +41,6 @@
 #include "catalog/indexing.h"
 #include "catalog/objectaccess.h"
 #include "catalog/pg_largeobject.h"
-#include "catalog/pg_largeobject_metadata.h"
 #include "libpq/libpq-fs.h"
 #include "miscadmin.h"
 #include "storage/large_object.h"
@@ -123,43 +122,6 @@ close_lo_relation(bool isCommit)
 }
 
 
-/*
- * Same as pg_largeobject.c's LargeObjectExists(), except snapshot to
- * read with can be specified.
- */
-static bool
-myLargeObjectExists(Oid loid, Snapshot snapshot)
-{
-   Relation    pg_lo_meta;
-   ScanKeyData skey[1];
-   SysScanDesc sd;
-   HeapTuple   tuple;
-   bool        retval = false;
-
-   ScanKeyInit(&skey[0],
-               Anum_pg_largeobject_metadata_oid,
-               BTEqualStrategyNumber, F_OIDEQ,
-               ObjectIdGetDatum(loid));
-
-   pg_lo_meta = table_open(LargeObjectMetadataRelationId,
-                           AccessShareLock);
-
-   sd = systable_beginscan(pg_lo_meta,
-                           LargeObjectMetadataOidIndexId, true,
-                           snapshot, 1, skey);
-
-   tuple = systable_getnext(sd);
-   if (HeapTupleIsValid(tuple))
-       retval = true;
-
-   systable_endscan(sd);
-
-   table_close(pg_lo_meta, AccessShareLock);
-
-   return retval;
-}
-
-
 /*
  * Extract data field from a pg_largeobject tuple, detoasting if needed
  * and verifying that the length is sane.  Returns data pointer (a bytea *),
@@ -279,7 +241,7 @@ inv_open(Oid lobjId, int flags, MemoryContext mcxt)
        snapshot = GetActiveSnapshot();
 
    /* Can't use LargeObjectExists here because we need to specify snapshot */
-   if (!myLargeObjectExists(lobjId, snapshot))
+   if (!LargeObjectExistsWithSnapshot(lobjId, snapshot))
        ereport(ERROR,
                (errcode(ERRCODE_UNDEFINED_OBJECT),
                 errmsg("large object %u does not exist", lobjId)));

diff --git a/src/include/catalog/pg_largeobject.h b/src/include/catalog/pg_largeobject.h
index b40c90b749db3a2d75cc2109f86be879f8d9fcf5..e684c58ca950d5b6b454d0f42b1f79d6265b47bf 100644 (file)
--- a/src/include/catalog/pg_largeobject.h
+++ b/src/include/catalog/pg_largeobject.h
@@ -20,6 +20,7 @@
 
 #include "catalog/genbki.h"
 #include "catalog/pg_largeobject_d.h"
+#include "utils/snapshot.h"
 
 /* ----------------
  *     pg_largeobject definition.  cpp turns this into
@@ -49,5 +50,6 @@ DECLARE_UNIQUE_INDEX_PKEY(pg_largeobject_loid_pn_index, 2683, LargeObjectLOidPNI
 extern Oid LargeObjectCreate(Oid loid);
 extern void LargeObjectDrop(Oid loid);
 extern bool LargeObjectExists(Oid loid);
+extern bool LargeObjectExistsWithSnapshot(Oid loid, Snapshot snapshot);
 
 #endif                         /* PG_LARGEOBJECT_H */