1.1 --- a/core.sql	Sun Aug 26 21:04:20 2012 +0200
     1.2 +++ b/core.sql	Tue Sep 25 02:32:51 2012 +0200
     1.3 @@ -2989,10 +2989,9 @@
     1.4    RETURNS VOID
     1.5    LANGUAGE 'plpgsql' VOLATILE AS $$
     1.6      BEGIN
     1.7 -      LOCK TABLE "member"     IN SHARE MODE;
     1.8 -      LOCK TABLE "privilege"  IN SHARE MODE;
     1.9 -      LOCK TABLE "membership" IN SHARE MODE;
    1.10 -      LOCK TABLE "policy"     IN SHARE MODE;
    1.11 +      -- The following locking order is used:
    1.12 +      -- 1st) row-level lock on the issue
    1.13 +      -- 2nd) table-level locks in order of occurrence in the core.sql file
    1.14        PERFORM NULL FROM "issue" WHERE "id" = "issue_id_p" FOR UPDATE;
    1.15        -- NOTE: The row-level exclusive lock in combination with the
    1.16        -- share_row_lock_issue(_via_initiative)_trigger functions (which
    1.17 @@ -3000,6 +2999,10 @@
    1.18        -- is changed, which could affect calculation of snapshots or
    1.19        -- counting of votes. Table "delegation" must be table-level-locked,
    1.20        -- as it also contains issue- and global-scope delegations.
    1.21 +      LOCK TABLE "member"     IN EXCLUSIVE MODE;  -- exclusive avoids deadlocks
    1.22 +      LOCK TABLE "privilege"  IN SHARE MODE;
    1.23 +      LOCK TABLE "membership" IN SHARE MODE;
    1.24 +      LOCK TABLE "policy"     IN SHARE MODE;
    1.25        LOCK TABLE "delegation" IN SHARE MODE;
    1.26        LOCK TABLE "direct_population_snapshot"     IN EXCLUSIVE MODE;
    1.27        LOCK TABLE "delegating_population_snapshot" IN EXCLUSIVE MODE;