Fix identify_locking_dependencies for schema-only dumps.

Without this fix, parallel restore of a schema-only dump can deadlock,
because when the dump is schema-only, the dependency will still be
pointing at the TABLE item rather than the TABLE DATA item.

Robert Haas and Tom Lane

diff --git a/src/bin/pg_dump/pg_backup_archiver.c b/src/bin/pg_dump/pg_backup_archiver.c
index dce326ade4ee806d762e028e9545fdc93c0a9531..4bb28d528c7645b6a99a0f4223548f34fe203631 100644 (file)
--- a/src/bin/pg_dump/pg_backup_archiver.c
+++ b/src/bin/pg_dump/pg_backup_archiver.c
@@ -4153,11 +4153,14 @@ identify_locking_dependencies(TocEntry *te)
        return;
 
    /*
-    * We assume the item requires exclusive lock on each TABLE DATA item
-    * listed among its dependencies.  (This was originally a dependency on
-    * the TABLE, but fix_dependencies repointed it to the data item. Note
-    * that all the entry types we are interested in here are POST_DATA, so
-    * they will all have been changed this way.)
+    * We assume the entry requires exclusive lock on each TABLE or TABLE DATA
+    * item listed among its dependencies.  Originally all of these would have
+    * been TABLE items, but repoint_table_dependencies would have repointed
+    * them to the TABLE DATA items if those are present (which they might not
+    * be, eg in a schema-only dump).  Note that all of the entries we are
+    * processing here are POST_DATA; otherwise there might be a significant
+    * difference between a dependency on a table and a dependency on its
+    * data, so that closer analysis would be needed here.
     */
    lockids = (DumpId *) malloc(te->nDeps * sizeof(DumpId));
    nlockids = 0;
@@ -4166,7 +4169,8 @@ identify_locking_dependencies(TocEntry *te)
        DumpId      depid = te->dependencies[i];
 
        if (depid <= maxDumpId && tocsByDumpId[depid - 1] &&
-           strcmp(tocsByDumpId[depid - 1]->desc, "TABLE DATA") == 0)
+           ((strcmp(tocsByDumpId[depid - 1]->desc, "TABLE DATA") == 0) ||
+             strcmp(tocsByDumpId[depid - 1]->desc, "TABLE") == 0))
            lockids[nlockids++] = depid;
    }