Use vectored I/O to fill new WAL segments. Instead of making many block-sized write() calls to fill a new WAL file with zeroes, make a smaller number of pwritev() calls (or various emulations). The actual number depends on the OS's IOV_MAX, which PG_IOV_MAX currently caps at 32. That means we'll write 256kB per call on typical systems. We may want to tune the number later with more experience.
Reviewed-by: Tom Lane <[email protected]> Reviewed-by: Andres Freund <[email protected]> Discussion: https://postgr.es/m/CA%2BhUKGJA%2Bu-220VONeoREBXJ9P3S94Y7J%2BkqCnTYmahvZJwM%3Dg%40mail.gmail.com Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/ce6a71fa5300cf00adf32c9daee302c523609709 Modified Files -------------- src/backend/access/transam/xlog.c | 28 ++++++++++++++++++++++------ 1 file changed, 22 insertions(+), 6 deletions(-)
