diff options
| -rw-r--r-- | src/backend/utils/activity/pgstat_io.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/src/backend/utils/activity/pgstat_io.c b/src/backend/utils/activity/pgstat_io.c index 6ff5d9e96a1..7aee6a396f2 100644 --- a/src/backend/utils/activity/pgstat_io.c +++ b/src/backend/utils/activity/pgstat_io.c @@ -107,6 +107,14 @@ pgstat_prepare_io_time(bool track_io_guc) /* * Like pgstat_count_io_op() except it also accumulates time. + * + * The calls related to pgstat_count_buffer_*() are for pgstat_database. As + * pg_stat_database only counts block read and write times, these are done for + * IOOP_READ, IOOP_WRITE and IOOP_EXTEND. + * + * pgBufferUsage is used for EXPLAIN. pgBufferUsage has write and read stats + * for shared, local and temporary blocks. pg_stat_io does not track the + * activity of temporary blocks, so these are ignored here. */ void pgstat_count_io_op_time(IOObject io_object, IOContext io_context, IOOp io_op, |