From 760d524980b76cccc738c0b2b434f24f1c159d7a Mon Sep 17 00:00:00 2001 From: Fujii Masao Date: Thu, 4 Sep 2025 22:23:24 +0900 Subject: [PATCH v2 1/2] pg_recvlogical: Prevent flushed data from being re-sent. Previously, when pg_recvlogical lost connection, reconnected, and restarted replication, data that had already been flushed could be streamed again. This happened because the replication start position used when restarting replication was taken from the last standby status message, which could be older than the position of the last flushed data. As a result, some flushed data newer than the replication start position could exist and be re-sent. This commit fixes the issue by ensuring all written data is flushed to disk before restarting replication, and by using the last flushed position as the replication start point. This prevents already flushed data from being re-sent. Additionally, previously when the --no-loop option was used, pg_recvlogical could exit without flushing written data, potentially losing data. To fix this issue, this commit also ensures all data is flushed to disk before exiting due to --no-loop. --- src/bin/pg_basebackup/pg_recvlogical.c | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-) diff --git a/src/bin/pg_basebackup/pg_recvlogical.c b/src/bin/pg_basebackup/pg_recvlogical.c index 14ad1504678..0354173bcbc 100644 --- a/src/bin/pg_basebackup/pg_recvlogical.c +++ b/src/bin/pg_basebackup/pg_recvlogical.c @@ -191,6 +191,13 @@ OutputFsync(TimestampTz now) output_fsync_lsn = output_written_lsn; + /* + * Save the last flushed position as the replication start point. On + * reconnect, replication resumes from there to avoid re-sending flushed + * data. + */ + startpos = output_fsync_lsn; + if (fsync_interval <= 0) return true; @@ -1025,8 +1032,18 @@ main(int argc, char **argv) */ exit(0); } - else if (noloop) + + /* + * Ensure all written data is flushed to disk before exiting or + * starting a new replication. + */ + if (outfd != -1 && strcmp(outfile, "-") != 0) + OutputFsync(feGetCurrentTimestamp()); + + if (noloop) + { pg_fatal("disconnected"); + } else { /* translator: check source for value for %d */ -- 2.51.2