commit 7a39f43 wrote: > --- a/src/backend/utils/activity/wait_event_names.txt > +++ b/src/backend/utils/activity/wait_event_names.txt > @@ -76,34 +76,35 @@ ABI_compatibility: > # Wait Events - Client > # > # Use this category when a process is waiting to send data to or receive data > # from the frontend process to which it is connected. This is never used for > # a background process, which has no client connection. > # > > Section: ClassName - WaitEventClient > > CLIENT_READ "Waiting to read data from the client." > CLIENT_WRITE "Waiting to write data to the client." > GSS_OPEN_SERVER "Waiting to read data from the client while > establishing a GSSAPI session." > LIBPQWALRECEIVER_CONNECT "Waiting in WAL receiver to establish > connection to remote server." > LIBPQWALRECEIVER_RECEIVE "Waiting in WAL receiver to receive data from > remote server." > SSL_OPEN_SERVER "Waiting for SSL while attempting connection." > WAIT_FOR_STANDBY_CONFIRMATION "Waiting for WAL to be received and > flushed by the physical standby." > -WAIT_FOR_WAL_FLUSH "Waiting for WAL flush to reach a target LSN on a > primary." > +WAIT_FOR_WAL_FLUSH "Waiting for WAL flush to reach a target LSN on a > primary or standby." > WAIT_FOR_WAL_REPLAY "Waiting for WAL replay to reach a target LSN on a > standby." > +WAIT_FOR_WAL_WRITE "Waiting for WAL write to reach a target LSN on a > standby." > WAL_SENDER_WAIT_FOR_WAL "Waiting for WAL to be flushed in WAL sender > process." > WAL_SENDER_WRITE_DATA "Waiting for any activity when processing > replies from WAL receiver in WAL sender process." > > ABI_compatibility:
WaitEventClient is about waiting for a socket to become readable or writable, so I think WAIT_FOR_WAL_* events don't fit in its scope. Sockets are just one of the ways to be in WAIT_FOR_WAL_*; other delay sources include local fsync and local replay, which could be disk-bound or CPU-bound. I think WAIT_FOR_WAL_* belong in WaitEventIPC. In the absence of objections, I'll change it that way: --- a/src/backend/utils/activity/wait_event_names.txt +++ b/src/backend/utils/activity/wait_event_names.txt @@ -91,5 +91,2 @@ SSL_OPEN_SERVER "Waiting for SSL while attempting connection." WAIT_FOR_STANDBY_CONFIRMATION "Waiting for WAL to be received and flushed by the physical standby." -WAIT_FOR_WAL_FLUSH "Waiting for WAL flush to reach a target LSN on a primary or standby." -WAIT_FOR_WAL_REPLAY "Waiting for WAL replay to reach a target LSN on a standby." -WAIT_FOR_WAL_WRITE "Waiting for WAL write to reach a target LSN on a standby." WAL_SENDER_WAIT_FOR_WAL "Waiting for WAL to be flushed in WAL sender process." @@ -164,2 +161,5 @@ SAFE_SNAPSHOT "Waiting to obtain a valid snapshot for a <literal>READ ONLY DEFER SYNC_REP "Waiting for confirmation from a remote server during synchronous replication." +WAIT_FOR_WAL_FLUSH "Waiting for WAL flush to reach a target LSN on a primary or standby." +WAIT_FOR_WAL_REPLAY "Waiting for WAL replay to reach a target LSN on a standby." +WAIT_FOR_WAL_WRITE "Waiting for WAL write to reach a target LSN on a standby." WAL_RECEIVER_EXIT "Waiting for the WAL receiver to exit." As further rationale, WaitEventClient says "never used for a background process". By xlogwait.c sizing its shmem to include NUM_AUXILIARY_PROCS, it's reserving the right to accept calls from background processes. As a side note related to that, the placement of WaitLSNCleanup() in ProcKill() but not AuxiliaryProcKill() would also need to change before welcoming auxiliary process use. Perhaps better than adding to AuxiliaryProcKill(), a separate on_shmem_exit callback for xlogwait.c would make it harder to miss callers needing it.
