Thread: pgsql: Truncate line pointer array during VACUUM.
Truncate line pointer array during VACUUM. Teach VACUUM to truncate the line pointer array of each heap page when a contiguous group of LP_UNUSED line pointers appear at the end of the array -- these unused and unreferenced items are excluded. This process occurs during VACUUM's second pass over the heap, right after LP_DEAD line pointers on the page (those encountered/pruned during the first pass) are marked LP_UNUSED. Truncation avoids line pointer bloat with certain workloads, particularly those involving continual range DELETEs and bulk INSERTs against the same table. Also harden heapam code to check for an out-of-range page offset number in places where we weren't already doing so. Author: Matthias van de Meent <boekewurm+postgres@gmail.com> Author: Peter Geoghegan <pg@bowt.ie> Reviewed-By: Masahiko Sawada <sawada.mshk@gmail.com> Reviewed-By: Peter Geoghegan <pg@bowt.ie> Discussion: https://postgr.es/m/CAEze2WjgaQc55Y5f5CQd3L=eS5CZcff2Obxp=O6pto8-f0hC4w@mail.gmail.com Discussion: https://postgr.es/m/CAH2-Wzn6a64PJM1Ggzm=uvx2otsopJMhFQj_g1rAj4GWr3ZSzw@mail.gmail.com Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/3c3b8a4b26891892bccf3d220580a7f413c0b9ca Modified Files -------------- src/backend/access/heap/heapam.c | 22 +++++-- src/backend/access/heap/pruneheap.c | 4 ++ src/backend/access/heap/vacuumlazy.c | 16 ++++- src/backend/storage/page/bufpage.c | 112 +++++++++++++++++++++++++++++++++-- src/include/storage/bufpage.h | 1 + 5 files changed, 144 insertions(+), 11 deletions(-)