From b0ee793df9a6d72df2f682aa2216707ecfb84a09 Mon Sep 17 00:00:00 2001 From: Michael Paquier Date: Wed, 6 Nov 2019 16:12:34 +0900 Subject: [PATCH] [#22929] YSQL: Fix Server's System Clock in XLogData in Logical Replication Summary: This diff imports the upstream PG commit `Fix timestamp of sent message for write context in logical decoding`-`5f6b1eb0cf4b0fb101478da51c294a63fd4726ef` PG commit: https://github.com/postgres/postgres/commit/5f6b1eb0cf4b0fb101478da51c294a63fd4726ef PG commit description: ``` When sending data for logical decoding using the streaming replication protocol via a WAL sender, the timestamp of the sent write message is allocated at the beginning of the message when preparing for the write, and actually computed when the write message is ready to be sent. The timestamp was getting computed after sending the message. This impacts anything using logical decoding, causing for example logical replication to report mostly NULL for last_msg_send_time in pg_stat_subscription. This commit makes sure that the timestamp is computed before sending the message. Discussion: https://postgr.es/m/CAMkU=1z=WMn8jt7iEdC5sYNaPgAgOASb_OW5JYv-vMdYaJSL-w@mail.gmail.com ``` Jira: DB-11846 Test Plan: Jenkins: test regex: .*ReplicationSlot.* Reviewers: asrinivasan, stiwary, skumar Reviewed By: asrinivasan Subscribers: yql, ycdcxcluster Differential Revision: https://phorge.dev.yugabyte.com/D36470 --- src/postgres/src/backend/replication/walsender.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/src/postgres/src/backend/replication/walsender.c b/src/postgres/src/backend/replication/walsender.c index 3a751add4678..de0150c3c834 100644 --- a/src/postgres/src/backend/replication/walsender.c +++ b/src/postgres/src/backend/replication/walsender.c @@ -1344,9 +1344,6 @@ WalSndWriteData(LogicalDecodingContext *ctx, XLogRecPtr lsn, TransactionId xid, if (IsYugaByteEnabled()) yb_start_time = GetCurrentTimestamp(); - /* output previously gathered data in a CopyData packet */ - pq_putmessage_noblock('d', ctx->out->data, ctx->out->len); - /* * Fill the send timestamp last, so that it is taken as late as possible. * This is somewhat ugly, but the protocol is set as it's already used for @@ -1358,6 +1355,9 @@ WalSndWriteData(LogicalDecodingContext *ctx, XLogRecPtr lsn, TransactionId xid, memcpy(&ctx->out->data[1 + sizeof(int64) + sizeof(int64)], tmpbuf.data, sizeof(int64)); + /* output previously gathered data in a CopyData packet */ + pq_putmessage_noblock('d', ctx->out->data, ctx->out->len); + CHECK_FOR_INTERRUPTS(); /* Try to flush pending output to the client */