---
src/backend/utils/cache/relmapper.c | 53 +++++++++++++++++++++++++++++++++++++
src/include/utils/relmapper.h | 2 ++
2 files changed, 55 insertions(+)
diff --git a/src/backend/utils/cache/relmapper.c b/src/backend/utils/cache/relmapper.c
index 6f21495..771f34d 100644
--- a/src/backend/utils/cache/relmapper.c
+++ b/src/backend/utils/cache/relmapper.c
@@ -180,6 +180,59 @@ RelationMapOidToFilenode(Oid relationId, bool shared)
return InvalidOid;
}
+/* RelationMapFilenodeToOid
+ *
+ * Do the reverse of the normal direction of mapping done in
+ * RelationMapOidToFilenode.
+ *
+ * This is not supposed to be used during normal running but rather for
+ * information purposes when looking at the filesystem or the xlog.
+ *
+ * Returns InvalidOid if the OID is not know which can easily happen if the
+ * filenode is not of a relation that is nailed or shared or if it simply
+ * doesn't exists anywhere.
+ */
+Oid
+RelationMapFilenodeToOid(Oid filenode, bool shared)
+{
+ const RelMapFile *map;
+ int32 i;
+
+ /* If there are active updates, believe those over the main maps */
+ if (shared)
+ {
+ map = &active_shared_updates;
+ for (i = 0; i < map->num_mappings; i++)
+ {
+ if (filenode == map->mappings[i].mapfilenode)
+ return map->mappings[i].mapoid;
+ }
+ map = &shared_map;
+ for (i = 0; i < map->num_mappings; i++)
+ {
+ if (filenode == map->mappings[i].mapfilenode)
+ return map->mappings[i].mapoid;
+ }
+ }
+ else
+ {
+ map = &active_local_updates;
+ for (i = 0; i < map->num_mappings; i++)
+ {
+ if (filenode == map->mappings[i].mapfilenode)
+ return map->mappings[i].mapoid;
+ }
+ map = &local_map;
+ for (i = 0; i < map->num_mappings; i++)
+ {
+ if (filenode == map->mappings[i].mapfilenode)
+ return map->mappings[i].mapoid;
+ }
+ }
+
+ return InvalidOid;
+}
+
/*
* RelationMapUpdateMap
*
diff --git a/src/include/utils/relmapper.h b/src/include/utils/relmapper.h
index 111a05c..4e56508 100644
--- a/src/include/utils/relmapper.h
+++ b/src/include/utils/relmapper.h
@@ -36,6 +36,8 @@ typedef struct xl_relmap_update
extern Oid RelationMapOidToFilenode(Oid relationId, bool shared);
+extern Oid RelationMapFilenodeToOid(Oid relationId, bool shared);
+
extern void RelationMapUpdateMap(Oid relationId, Oid fileNode, bool shared,
bool immediate);
--
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