From d940fa8bd8175fa27f311297b18bd99569d8a947 Mon Sep 17 00:00:00 2001 From: Fujii Masao Date: Thu, 4 Sep 2025 22:23:24 +0900 Subject: [PATCH v1] 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 7a4d1a2d2ca..a3c039ddc49 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 */ -- 2.50.1