diff options
| author | Alexander Korotkov <akorotkov@postgresql.org> | 2025-04-02 12:44:24 +0300 |
|---|---|---|
| committer | Alexander Korotkov <akorotkov@postgresql.org> | 2025-04-02 12:44:24 +0300 |
| commit | bc22dc0e0ddc2dcb6043a732415019cc6b6bf683 (patch) | |
| tree | 34fbf986ac05c0655f894ec056c9aba4f49eed5e /src/backend/utils/activity | |
| parent | b53b88109f94bd81ed0ac580035a936000bc2865 (diff) | |
Get rid of WALBufMappingLock
Allow multiple backends to initialize WAL buffers concurrently. This way
`MemSet((char *) NewPage, 0, XLOG_BLCKSZ);` can run in parallel without
taking a single LWLock in exclusive mode.
The new algorithm works as follows:
* reserve a page for initialization using XLogCtl->InitializeReserved,
* ensure the page is written out,
* once the page is initialized, try to advance XLogCtl->InitializedUpTo and
signal to waiters using XLogCtl->InitializedUpToCondVar condition
variable,
* repeat previous steps until we reserve initialization up to the target
WAL position,
* wait until concurrent initialization finishes using a
XLogCtl->InitializedUpToCondVar.
Now, multiple backends can, in parallel, concurrently reserve pages,
initialize them, and advance XLogCtl->InitializedUpTo to point to the latest
initialized page.
Author: Yura Sokolov <y.sokolov@postgrespro.ru>
Co-authored-by: Alexander Korotkov <aekorotkov@gmail.com>
Reviewed-by: Pavel Borisov <pashkin.elfe@gmail.com>
Reviewed-by: Tomas Vondra <tomas@vondra.me>
Tested-by: Michael Paquier <michael@paquier.xyz>
Diffstat (limited to 'src/backend/utils/activity')
| -rw-r--r-- | src/backend/utils/activity/wait_event_names.txt | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/src/backend/utils/activity/wait_event_names.txt b/src/backend/utils/activity/wait_event_names.txt index 4f44648aca8..8bce14c38fd 100644 --- a/src/backend/utils/activity/wait_event_names.txt +++ b/src/backend/utils/activity/wait_event_names.txt @@ -156,6 +156,7 @@ REPLICATION_SLOT_DROP "Waiting for a replication slot to become inactive so it c RESTORE_COMMAND "Waiting for <xref linkend="guc-restore-command"/> to complete." SAFE_SNAPSHOT "Waiting to obtain a valid snapshot for a <literal>READ ONLY DEFERRABLE</literal> transaction." SYNC_REP "Waiting for confirmation from a remote server during synchronous replication." +WAL_BUFFER_INIT "Waiting on WAL buffer to be initialized." WAL_RECEIVER_EXIT "Waiting for the WAL receiver to exit." WAL_RECEIVER_WAIT_START "Waiting for startup process to send initial data for streaming replication." WAL_SUMMARY_READY "Waiting for a new WAL summary to be generated." @@ -314,7 +315,6 @@ XidGen "Waiting to allocate a new transaction ID." ProcArray "Waiting to access the shared per-process data structures (typically, to get a snapshot or report a session's transaction ID)." SInvalRead "Waiting to retrieve messages from the shared catalog invalidation queue." SInvalWrite "Waiting to add a message to the shared catalog invalidation queue." -WALBufMapping "Waiting to replace a page in WAL buffers." WALWrite "Waiting for WAL buffers to be written to disk." ControlFile "Waiting to read or update the <filename>pg_control</filename> file or create a new WAL file." MultiXactGen "Waiting to read or update shared multixact state." |