Add more temporary debug logging, in 9.4 branch only.

Last night's results were inconclusive, but after more staring at the
code I've thought of some more data to gather.

Discussion: https://postgr.es/m/6744.1523833660@sss.pgh.pa.us

diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index e8b9d1a4dd8b07b97f42a4bc2b11b4bf66cc825a..f3b9ef27d2bb540d334828fa226f85b927044bc4 100644 (file)
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -773,6 +773,8 @@ DefineIndex(Oid relationId,
 
        PopActiveSnapshot();
        PrintSnapMgrStatus("concurrent index build, after PopActiveSnapshot");
+       elog(LOG, "concurrent index build: releasing snap %p with regd_count %d, active_count %d",
+                snapshot, snapshot->regd_count, snapshot->active_count);
        UnregisterSnapshot(snapshot);
        PrintSnapMgrStatus("concurrent index build, after UnregisterSnapshot");
        InvalidateCatalogSnapshot();

diff --git a/src/backend/utils/time/snapmgr.c b/src/backend/utils/time/snapmgr.c
index 2a3d915e1f9beed43154c60852da6f862a7e06ec..dbb3544af7b85fe053b6294f42b116b9334dc1bb 100644 (file)
--- a/src/backend/utils/time/snapmgr.c
+++ b/src/backend/utils/time/snapmgr.c
@@ -1411,7 +1411,7 @@ PrintSnapMgrStatus(const char *context)
        for (active = ActiveSnapshot; active != NULL; active = active->as_next)
                asdepth++;
 
-       elog(LOG, "%s: %d reg snaps, %d active snaps, cat snap %p, xmin %u",
+       elog(LOG, "%s: %d reg snaps, %d active snaps, first snap %p, cat snap %p, xmin %u",
                 context, RegisteredSnapshots, asdepth,
-                CatalogSnapshot, MyPgXact->xmin);
+                FirstXactSnapshot, CatalogSnapshot, MyPgXact->xmin);
 }