From d5eb1fe0dc717acae5da610c47468d3472d646a4 Mon Sep 17 00:00:00 2001 From: Michael Paquier Date: Thu, 12 Jul 2018 10:20:14 +0900 Subject: [PATCH] Make logical WAL sender report streaming state appropriately WAL senders sending logically-decoded data fail to properly report in "streaming" state when starting up, hence as long as one extra record is not replayed, such WAL senders would remain in a "catchup" state, which is inconsistent with the physical cousin. This can be easily reproduced by for example using pg_recvlogical and restarting the upstream server. The TAP tests have been slightly modified to detect the failure and strengthened so as future tests also make sure that a node is in streaming state when waiting for its catchup. Backpatch down to 9.4 where this code has been introduced. Reported-by: Sawada Masahiko Author: Simon Riggs, Sawada Masahiko Reviewed-by: Petr Jelinek, Michael Paquier, Vaishnavi Prabakaran Discussion: https://postgr.es/m/CAD21AoB2ZbCCqOx=bgKMcLrAvs1V0ZMqzs7wBTuDySezTGtMZA@mail.gmail.com --- src/backend/replication/walsender.c | 22 ++++++++++++++++------ 1 file changed, 16 insertions(+), 6 deletions(-) diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 4e06ffc6862..ac11bf57244 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1926,8 +1926,8 @@ WalSndLoop(WalSndSendDataCallback send_data) if (MyWalSnd->state == WALSNDSTATE_CATCHUP) { ereport(DEBUG1, - (errmsg("standby \"%s\" has now caught up with primary", - application_name))); + (errmsg("\"%s\" has now caught up with upstream server", + application_name))); WalSndSetState(WALSNDSTATE_STREAMING); } @@ -2483,10 +2483,10 @@ XLogSendLogical(void) char *errm; /* - * Don't know whether we've caught up yet. We'll set it to true in - * WalSndWaitForWal, if we're actually waiting. We also set to true if - * XLogReadRecord() had to stop reading but WalSndWaitForWal didn't wait - - * i.e. when we're shutting down. + * Don't know whether we've caught up yet. We'll set WalSndCaughtUp to + * true in WalSndWaitForWal, if we're actually waiting. We also set to + * true if XLogReadRecord() had to stop reading but WalSndWaitForWal + * didn't wait - i.e. when we're shutting down. */ WalSndCaughtUp = false; @@ -2499,9 +2499,19 @@ XLogSendLogical(void) if (record != NULL) { + /* XXX: Note that logical decoding cannot be used while in recovery */ + XLogRecPtr flushPtr = GetFlushRecPtr(); + LogicalDecodingProcessRecord(logical_decoding_ctx, logical_decoding_ctx->reader); sentPtr = logical_decoding_ctx->reader->EndRecPtr; + + /* + * If we have sent a record that is at or beyond the flushed point, we + * have caught up. + */ + if (sentPtr >= flushPtr) + WalSndCaughtUp = true; } else {