Make pg_stat_io count IOs as bytes instead of blocks for some operations Currently in pg_stat_io view, IOs are counted as blocks of size BLCKSZ. There are two limitations with this design: * The actual number of I/O requests sent to the kernel is lower because I/O requests may be merged before being sent. Additionally, it gives the impression that all I/Os are done in block size, which shadows the benefits of merging I/O requests. * Some patches are under work to extend pg_stat_io for the tracking of operations that may not be linked to the block size. For example, WAL read IOs are done in variable bytes and it is not possible to correctly show these IOs in pg_stat_io view, and we want to keep all this data in a single system view rather than spread it across multiple relations to ease monitoring.
WaitReadBuffers() can now be tracked as a single read operation worth N blocks. Same for ExtendBufferedRelShared() and ExtendBufferedRelLocal() for extensions. Three columns are added to pg_stat_io for reads, writes and extensions for the byte calculations. op_bytes, which was always hardcoded to BLCKSZ, is removed. IO backend statistics are updated to reflect these changes. Bump catalog version. Author: Nazir Bilal Yavuz Reviewed-by: Bertrand Drouvot, Melanie Plageman Discussion: https://postgr.es/m/CAN55FZ0oqxBaaHAEsj=xFqkzE3n5P=3ra1v_igxwl-rv7qr...@mail.gmail.com Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/f92c854cf406a5ad34c9aa92416d578819704aa2 Modified Files -------------- doc/src/sgml/monitoring.sgml | 51 ++++++++++------- src/backend/catalog/system_views.sql | 4 +- src/backend/storage/buffer/bufmgr.c | 14 ++--- src/backend/storage/buffer/localbuf.c | 7 ++- src/backend/storage/smgr/md.c | 4 +- src/backend/utils/activity/pgstat_backend.c | 2 + src/backend/utils/activity/pgstat_io.c | 20 ++++++- src/backend/utils/adt/pgstatfuncs.c | 86 ++++++++++++++++++++++------- src/include/catalog/catversion.h | 2 +- src/include/catalog/pg_proc.dat | 12 ++-- src/include/pgstat.h | 27 +++++++-- src/test/regress/expected/rules.out | 6 +- 12 files changed, 164 insertions(+), 71 deletions(-)