postgres-github.git / summary / log / commit / refs

commit    b46e1e54d078def33b840ae1fa6c5236a7b12ec2
Author:   Melanie Plageman <melanieplageman@gmail.com>
Date:     Mon Mar 30 19:47:07 2026 +0000

    Allow on-access pruning to set pages all-visible
    
    Many queries do not modify the underlying relation. For such queries, if
    on-access pruning occurs during the scan, we can check whether the page
    has become all-visible and update the visibility map accordingly.
    Previously, only vacuum and COPY FREEZE marked pages as all-visible or
    all-frozen.
    
    This commit implements on-access VM setting for sequential scans, tid
    range scans, sample scans, bitmap heap scans, and the underlying heap
    relation in index scans.
    
    Setting the visibility map on-access can avoid write amplification
    caused by vacuum later needing to set the page all-visible, which could
    trigger a write and potentially an FPI. It also allows more frequent
    index-only scans, since they require pages to be marked all-visible in
    the VM.
    
    Author: Melanie Plageman <melanieplageman@gmail.com>
    Reviewed-by: Andres Freund <andres@anarazel.de>
    Reviewed-by: Kirill Reshke <reshkekirill@gmail.com>
    Reviewed-by: Chao Li <li.evan.chao@gmail.com>
    Discussion: https://postgr.es/m/flat/CAAKRu_ZMw6Npd_qm2KM%2BFwQ3cMOMx1Dh3VMhp8-V7SOLxdK9-g%40mail.gmail.com

[parent: e3637a05dc43]