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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".
This commit is contained in:
Tom Lane
2015-01-25 22:49:56 -05:00
parent bf007a27ac
commit c70f9e8988

View File

@ -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;