Further cleanup of ReorderBufferCommit().

On closer inspection, we can remove the "volatile" qualifier on
"using_subtxn" so long as we initialize that before the PG_TRY block,
which there's no particularly good reason not to do.
Also, push the "change" variable inside the PG_TRY so as to remove
all question of whether it needs "volatile", and remove useless
early initializations of "snapshow_now" and "using_subtxn".

diff --git a/src/backend/replication/logical/reorderbuffer.c b/src/backend/replication/logical/reorderbuffer.c
index 82f83d1450516e488c2e8bbfabf3bcacc39bd673..bcd58966f0aca69858ec4eccf707bfbfb826d380 100644 (file)
--- a/src/backend/replication/logical/reorderbuffer.c
+++ b/src/backend/replication/logical/reorderbuffer.c
@@ -1258,12 +1258,10 @@ ReorderBufferCommit(ReorderBuffer *rb, TransactionId xid,
                    TimestampTz commit_time)
 {
    ReorderBufferTXN *txn;
-   ReorderBufferIterTXNState *volatile iterstate = NULL;
-   ReorderBufferChange *change;
-
+   volatile Snapshot snapshot_now;
    volatile CommandId command_id = FirstCommandId;
-   volatile Snapshot snapshot_now = NULL;
-   volatile bool using_subtxn = false;
+   bool        using_subtxn;
+   ReorderBufferIterTXNState *volatile iterstate = NULL;
 
    txn = ReorderBufferTXNByXid(rb, xid, false, NULL, InvalidXLogRecPtr,
                                false);
@@ -1301,19 +1299,21 @@ ReorderBufferCommit(ReorderBuffer *rb, TransactionId xid,
    /* setup the initial snapshot */
    SetupHistoricSnapshot(snapshot_now, txn->tuplecid_hash);
 
+   /*
+    * Decoding needs access to syscaches et al., which in turn use
+    * heavyweight locks and such. Thus we need to have enough state around to
+    * keep track of those.  The easiest way is to simply use a transaction
+    * internally.  That also allows us to easily enforce that nothing writes
+    * to the database by checking for xid assignments.
+    *
+    * When we're called via the SQL SRF there's already a transaction
+    * started, so start an explicit subtransaction there.
+    */
+   using_subtxn = IsTransactionOrTransactionBlock();
+
    PG_TRY();
    {
-       /*
-        * Decoding needs access to syscaches et al., which in turn use
-        * heavyweight locks and such. Thus we need to have enough state
-        * around to keep track of those. The easiest way is to simply use a
-        * transaction internally. That also allows us to easily enforce that
-        * nothing writes to the database by checking for xid assignments.
-        *
-        * When we're called via the SQL SRF there's already a transaction
-        * started, so start an explicit subtransaction there.
-        */
-       using_subtxn = IsTransactionOrTransactionBlock();
+       ReorderBufferChange *change;
 
        if (using_subtxn)
            BeginInternalSubTransaction("replay");
@@ -1323,7 +1323,7 @@ ReorderBufferCommit(ReorderBuffer *rb, TransactionId xid,
        rb->begin(rb, txn);
 
        iterstate = ReorderBufferIterTXNInit(rb, txn);
-       while ((change = ReorderBufferIterTXNNext(rb, iterstate)))
+       while ((change = ReorderBufferIterTXNNext(rb, iterstate)) != NULL)
        {
            Relation    relation = NULL;
            Oid         reloid;