On Tue, Jan 30, 2024 at 6:24 AM Masahiko Sawada <sawada.m...@gmail.com> wrote: > > Hi, > > While working on radix tree patch[1], John Naylor found that dsa.c > doesn't already use shared locks even in dsa_dump(). dsa_dump() seems > a pure read-only function so I thought we could use a shared lock mode > there. Is there any reason to use exclusive mode even in dsa_dump()?
check_for_freed_segments_locked which is called from dsa_dump does mark a few variables of the dsa area to NULL right? Are you suggesting to take initially a shared lock in dsa_dump and upgrade it to exclusive mode in the unlikely event of unlikely(area->freed_segment_counter != freed_segment_counter) occurring in check_for_freed_segments_locked? > Ultimately, since we're trying to add a new function > dsa_get_total_size() that just returns > dsa_area_control.total_segment_size and therefore would also be a > read-only function, I'd like to find out the correct lock mode there. > > [1] > https://www.postgresql.org/message-id/CANWCAZYYzoKp_4%2B1m5mn-TRD62BTwom8iLXLOWMsHkkwFi%3Drzg%40mail.gmail.com Do you see any lock contention or any other issues with exclusive locks on dsa areas? -- Bharath Rupireddy PostgreSQL Contributors Team RDS Open Source Databases Amazon Web Services: https://aws.amazon.com
