diff options
Diffstat (limited to 'src/backend/postmaster')
| -rw-r--r-- | src/backend/postmaster/bgwriter.c | 16 | ||||
| -rw-r--r-- | src/backend/postmaster/pgstat.c | 1 |
2 files changed, 13 insertions, 4 deletions
diff --git a/src/backend/postmaster/bgwriter.c b/src/backend/postmaster/bgwriter.c index 0690ab521e..620b1972a6 100644 --- a/src/backend/postmaster/bgwriter.c +++ b/src/backend/postmaster/bgwriter.c @@ -102,13 +102,15 @@ * * num_backend_writes is used to count the number of buffer writes performed * by non-bgwriter processes. This counter should be wide enough that it - * can't overflow during a single bgwriter cycle. + * can't overflow during a single bgwriter cycle. num_backend_fsync + * counts the subset of those writes that also had to do their own fsync, + * because the background writer failed to absorb their request. * * The requests array holds fsync requests sent by backends and not yet * absorbed by the bgwriter. * - * Unlike the checkpoint fields, num_backend_writes and the requests - * fields are protected by BgWriterCommLock. + * Unlike the checkpoint fields, num_backend_writes, num_backend_fsync, and + * the requests fields are protected by BgWriterCommLock. *---------- */ typedef struct @@ -132,6 +134,7 @@ typedef struct int ckpt_flags; /* checkpoint flags, as defined in xlog.h */ uint32 num_backend_writes; /* counts non-bgwriter buffer writes */ + uint32 num_backend_fsync; /* counts non-bgwriter fsync calls */ int num_requests; /* current # of requests */ int max_requests; /* allocated array size */ @@ -1084,12 +1087,14 @@ ForwardFsyncRequest(RelFileNodeBackend rnode, ForkNumber forknum, LWLockAcquire(BgWriterCommLock, LW_EXCLUSIVE); - /* we count non-bgwriter writes even when the request queue overflows */ + /* Count all backend writes regardless of if they fit in the queue */ BgWriterShmem->num_backend_writes++; if (BgWriterShmem->bgwriter_pid == 0 || BgWriterShmem->num_requests >= BgWriterShmem->max_requests) { + /* Also count the subset where backends have to do their own fsync */ + BgWriterShmem->num_backend_fsync++; LWLockRelease(BgWriterCommLock); return false; } @@ -1137,7 +1142,10 @@ AbsorbFsyncRequests(void) /* Transfer write count into pending pgstats message */ BgWriterStats.m_buf_written_backend += BgWriterShmem->num_backend_writes; + BgWriterStats.m_buf_fsync_backend += BgWriterShmem->num_backend_fsync; + BgWriterShmem->num_backend_writes = 0; + BgWriterShmem->num_backend_fsync = 0; n = BgWriterShmem->num_requests; if (n > 0) diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c index a1ad342953..c3c136a161 100644 --- a/src/backend/postmaster/pgstat.c +++ b/src/backend/postmaster/pgstat.c @@ -4188,6 +4188,7 @@ pgstat_recv_bgwriter(PgStat_MsgBgWriter *msg, int len) globalStats.buf_written_clean += msg->m_buf_written_clean; globalStats.maxwritten_clean += msg->m_maxwritten_clean; globalStats.buf_written_backend += msg->m_buf_written_backend; + globalStats.buf_fsync_backend += msg->m_buf_fsync_backend; globalStats.buf_alloc += msg->m_buf_alloc; } |