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.soko...@postgrespro.ru> Co-authored-by: Alexander Korotkov <aekorot...@gmail.com> Reviewed-by: Pavel Borisov <pashkin.e...@gmail.com> Reviewed-by: Tomas Vondra <to...@vondra.me> Tested-by: Michael Paquier <mich...@paquier.xyz> Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/bc22dc0e0ddc2dcb6043a732415019cc6b6bf683 Modified Files -------------- src/backend/access/transam/xlog.c | 234 +++++++++++++++++++----- src/backend/utils/activity/wait_event_names.txt | 2 +- src/include/storage/lwlocklist.h | 2 +- 3 files changed, 189 insertions(+), 49 deletions(-)
