bdr: Clean up remote update replay code a bit.

diff --git a/contrib/bdr/bdr_apply.c b/contrib/bdr/bdr_apply.c
index e80f98c6a0f48fa5c619e1aa810a1723ab2ed37c..1d2bd44f9a562ace28b5a5e666b6bac9250a0756 100644 (file)
--- a/contrib/bdr/bdr_apply.c
+++ b/contrib/bdr/bdr_apply.c
@@ -74,7 +74,7 @@ static void tuple_to_stringinfo(StringInfo s, TupleDesc tupdesc, HeapTuple tuple
 
 static void check_sequencer_wakeup(Relation rel);
 
-static bool check_apply_update(RepNodeId local_node_id, TimestampTz ts, bool *log_update);
+static void check_apply_update(RepNodeId local_node_id, TimestampTz ts, bool *perform_update, bool *log_update);
 static void do_log_update(RepNodeId local_node_id, bool apply_update, TimestampTz ts, Relation idxrel, HeapTuple old_key);
 static void do_apply_update(Relation rel, ItemPointerData oldtid, HeapTuple old_tuple, BDRTupleData new_tuple);
 
@@ -485,7 +485,7 @@ process_remote_update(StringInfo s)
        Buffer      buf;
        bool        found;
        TransactionId xmin;
-       TimestampTz ts;
+       TimestampTz local_ts;
        RepNodeId   local_node_id;
        bool        apply_update;
        bool        log_update;
@@ -510,13 +510,13 @@ process_remote_update(StringInfo s)
         * strategy for this, except when the new update comes from the same
         * node that originated the previous version of the tuple.
         */
-       TransactionIdGetCommitTsData(xmin, &ts, &local_node_id_raw);
+       TransactionIdGetCommitTsData(xmin, &local_ts, &local_node_id_raw);
        local_node_id = local_node_id_raw;
 
-       apply_update = check_apply_update(local_node_id, ts, &log_update);
+       check_apply_update(local_node_id, local_ts, &apply_update, &log_update);
 
        if (log_update)
-           do_log_update(local_node_id, apply_update, ts, idxrel, old_key);
+           do_log_update(local_node_id, apply_update, local_ts, idxrel, old_key);
 
        if (apply_update)
            do_apply_update(rel, oldtid, old_tuple, new_tuple);
@@ -541,8 +541,15 @@ process_remote_update(StringInfo s)
    heap_close(rel, NoLock);
 }
 
-static bool
-check_apply_update(RepNodeId local_node_id, TimestampTz ts, bool *log_update)
+/*
+ * Check whether a remote update conflicts with the local row version.
+ *
+ * perform_update, log_update is set to true if the update should be performed
+ * and logged respectively
+ */
+static void
+check_apply_update(RepNodeId local_node_id, TimestampTz local_ts,
+                  bool *perform_update, bool *log_update)
 {
    uint64      local_sysid,
                remote_sysid;
@@ -558,8 +565,8 @@ check_apply_update(RepNodeId local_node_id, TimestampTz ts, bool *log_update)
         * timing; that's just too common and valid since normal row level
         * locking guarantees are met.
         */
+       *perform_update = true;
        *log_update = false;
-       return true;
    }
    else
    {
@@ -569,43 +576,46 @@ check_apply_update(RepNodeId local_node_id, TimestampTz ts, bool *log_update)
         * sysid + TLI to discern.
         */
 
-       cmp = timestamptz_cmp_internal(replication_origin_timestamp, ts);
+       cmp = timestamptz_cmp_internal(replication_origin_timestamp,
+                                      local_ts);
 
        if (cmp > 0)
        {
+           *perform_update = true;
            *log_update = false;
-           return true;
+           return;
        }
        else if (cmp == 0)
        {
-           *log_update = true;
-
            fetch_sysid_via_node_id(local_node_id,
                                    &local_sysid, &local_tli);
            fetch_sysid_via_node_id(bdr_apply_con->origin_id,
                                    &remote_sysid, &remote_tli);
 
            if (local_sysid < remote_sysid)
-               return true;
+               *perform_update = true;
            else if (local_sysid > remote_sysid)
-               return false;
+               *perform_update = false;
            else if (local_tli < remote_tli)
-               return true;
+               *perform_update = true;
            else if (local_tli > remote_tli)
-               return false;
+               *perform_update =  false;
            else
                /* shouldn't happen */
                elog(ERROR, "unsuccessful node comparison");
+
+           *log_update = true;
+           return;
        }
        else
        {
+           *perform_update = false;
            *log_update = true;
-           return false;
+           return;
        }
    }
 
-   /* XXX dead code */
-   return false;
+   elog(ERROR, "unreachable code");
 }
 
 static void