On 20/03/2013 16:33, Alvaro Herrera wrote:
Marc Cousin escribió:
Hi,
I'm trying to write a background writer, and I'm facing a problem with
timestamps. The following code is where I'm having a problem (it's just a demo
for
the problem):
BackgroundWorkerInitializeConnection("test", NULL);
while (!got_sigterm)
{
int ret;
/* Wait 1s */
ret = WaitLatch(&MyProc->procLatch,
WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
1000L);
ResetLatch(&MyProc->procLatch);
/* Insert dummy for now */
StartTransactionCommand();
SPI_connect();
PushActiveSnapshot(GetTransactionSnapshot());
ret = SPI_execute("INSERT INTO log VALUES
(now(),statement_timestamp(),clock_timestamp())", false, 0);
SPI_finish();
PopActiveSnapshot();
CommitTransactionCommand();
}
Ah. The reason for this problem is that the statement start time (which
also sets the transaction start time, when it's the first statement) is
set by postgres.c, not the transaction-control functions in xact.c. So
you'd need to add a SetCurrentStatementStartTimestamp() call somewhere
in your loop.
Yes, that works. Thanks a lot !
Maybe this should be added to the worker_spi example ?
Regards
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