diff options
| -rw-r--r-- | src/backend/replication/walsender.c | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 1ce21a2ad98..548eafa7a73 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -233,6 +233,19 @@ typedef struct int write_head; int read_heads[NUM_SYNC_REP_WAIT_MODE]; WalTimeSample last_read[NUM_SYNC_REP_WAIT_MODE]; + + /* + * Overflow entries for read heads that collide with the write head. + * + * When the cyclic buffer fills (write head is about to collide with a + * read head), we save that read head's current sample here and mark it as + * using overflow (read_heads[i] = -1). This allows the write head to + * continue advancing while the overflowed mode continues lag computation + * using the saved sample. + * + * Once the standby's reported LSN advances past the overflow entry's LSN, + * we transition back to normal buffer-based tracking. + */ WalTimeSample overflowed[NUM_SYNC_REP_WAIT_MODE]; } LagTracker; |