diff options
| author | Alvaro Herrera <alvherre@alvh.no-ip.org> | 2016-07-01 13:53:46 -0400 |
|---|---|---|
| committer | Alvaro Herrera <alvherre@alvh.no-ip.org> | 2016-07-01 13:53:46 -0400 |
| commit | 1bdae16fca884a9190dc330790e7a63c04989fa3 (patch) | |
| tree | efd2fe00b1e7f4065ee443d69b7afa276baf8423 | |
| parent | 9e703987a8a1961af8edd751169a8ae1055890eb (diff) | |
| download | postgresql-1bdae16fca884a9190dc330790e7a63c04989fa3.tar.gz postgresql-1bdae16fca884a9190dc330790e7a63c04989fa3.zip | |
walreceiver: tweak pg_stat_wal_receiver behavior
There are two problems in the original coding: one is that if one
walreceiver process exits, the ready_to_display flag remains set in
shared memory, exposing the conninfo of the next walreceiver before
obfuscating. Fix by having WalRcvDie reset the flag.
Second, the sleep-and-retry behavior that waited until walreceiver had
set ready_to_display wasn't liked; the preference is to have it return
no data instead, so let's do that.
Bugs in 9ed551e0a reported by Fujii Masao and Michël Paquier.
Author: Michaël Paquier
| -rw-r--r-- | src/backend/replication/walreceiver.c | 22 |
1 files changed, 6 insertions, 16 deletions
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c index d552f04901c..413ee3a5c18 100644 --- a/src/backend/replication/walreceiver.c +++ b/src/backend/replication/walreceiver.c @@ -246,6 +246,7 @@ WalReceiverMain(void) walrcv->walRcvState = WALRCV_STREAMING; /* Fetch information required to start streaming */ + walrcv->ready_to_display = false; strlcpy(conninfo, (char *) walrcv->conninfo, MAXCONNINFO); strlcpy(slotname, (char *) walrcv->slotname, NAMEDATALEN); startpoint = walrcv->receiveStart; @@ -770,6 +771,7 @@ WalRcvDie(int code, Datum arg) Assert(walrcv->pid == MyProcPid); walrcv->walRcvState = WALRCV_STOPPED; walrcv->pid = 0; + walrcv->ready_to_display = false; SpinLockRelease(&walrcv->mutex); /* Terminate the connection gracefully. */ @@ -1343,24 +1345,12 @@ pg_stat_get_wal_receiver(PG_FUNCTION_ARGS) char *slotname; char *conninfo; - /* No WAL receiver, just return a tuple with NULL values */ - if (walrcv->pid == 0) - PG_RETURN_NULL(); - /* - * Users attempting to read this data mustn't be shown security sensitive - * data, so sleep until everything has been properly obfuscated. + * No WAL receiver (or not ready yet), just return a tuple with NULL + * values */ -retry: - SpinLockAcquire(&walrcv->mutex); - if (!walrcv->ready_to_display) - { - SpinLockRelease(&walrcv->mutex); - CHECK_FOR_INTERRUPTS(); - pg_usleep(1000); - goto retry; - } - SpinLockRelease(&walrcv->mutex); + if (walrcv->pid == 0 || !walrcv->ready_to_display) + PG_RETURN_NULL(); /* determine result type */ if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE) |