# HG changeset patch
# User jbe
# Date 1347548542 -7200
# Node ID 69d6fba0f84cbb9f3d591f40147a67433ee0ef0a
# Parent  e818f83e133bc545681b4bc06ce3c4f280de4672
Use EXCLUSIVE MODE table locks in function "lock_issue"("issue"."id")

Avoids deadlocks caused by explicit FOR UPDATE row locks when updating member statements and implicit FOR SHARE row locks when writing snapshots.

diff -r e818f83e133b -r 69d6fba0f84c core.sql
--- a/core.sql	Wed Jun 20 21:22:02 2012 +0200
+++ b/core.sql	Thu Sep 13 17:02:22 2012 +0200
@@ -2925,10 +2925,10 @@
   RETURNS VOID
   LANGUAGE 'plpgsql' VOLATILE AS $$
     BEGIN
-      LOCK TABLE "member"     IN SHARE MODE;
-      LOCK TABLE "privilege"  IN SHARE MODE;
-      LOCK TABLE "membership" IN SHARE MODE;
-      LOCK TABLE "policy"     IN SHARE MODE;
+      LOCK TABLE "member"     IN EXCLUSIVE MODE;
+      LOCK TABLE "privilege"  IN EXCLUSIVE MODE;
+      LOCK TABLE "membership" IN EXCLUSIVE MODE;
+      LOCK TABLE "policy"     IN EXCLUSIVE MODE;
       PERFORM NULL FROM "issue" WHERE "id" = "issue_id_p" FOR UPDATE;
       -- NOTE: The row-level exclusive lock in combination with the
       -- share_row_lock_issue(_via_initiative)_trigger functions (which
@@ -2936,7 +2936,7 @@
       -- is changed, which could affect calculation of snapshots or
       -- counting of votes. Table "delegation" must be table-level-locked,
       -- as it also contains issue- and global-scope delegations.
-      LOCK TABLE "delegation" IN SHARE MODE;
+      LOCK TABLE "delegation" IN EXCLUSIVE MODE;
       LOCK TABLE "direct_population_snapshot"     IN EXCLUSIVE MODE;
       LOCK TABLE "delegating_population_snapshot" IN EXCLUSIVE MODE;
       LOCK TABLE "direct_interest_snapshot"       IN EXCLUSIVE MODE;