Unpin buffer before inplace update waits for an XID to end. Commit a07e03fd8fa7daf4d1356f7cb501ffe784ea6257 changed inplace updates to wait for heap_update() commands like GRANT TABLE and GRANT DATABASE. By keeping the pin during that wait, a sequence of autovacuum workers and an uncommitted GRANT starved one foreground LockBufferForCleanup() for six minutes, on buildfarm member sarus. Prevent, at the cost of a bit of complexity. Back-patch to v12, like the earlier commit. That commit and heap_inplace_lock() have not yet appeared in any release.
Discussion: https://postgr.es/m/20241026184936.ae.nmi...@google.com Branch ------ REL_17_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/9aef6f19ac27a607f0c557d19934d5ce96ed5f1a Modified Files -------------- src/backend/access/heap/heapam.c | 10 +++++++--- src/backend/access/index/genam.c | 12 +++++------- src/include/access/heapam.h | 3 ++- 3 files changed, 14 insertions(+), 11 deletions(-)