On Tue, Jan 21, 2020 at 11:30 AM Andres Freund <and...@anarazel.de> wrote: > > Hi, > > On 2020-01-20 09:09:35 +0530, Amit Kapila wrote: > > Pushed, after fixing these two comments. > > When attempting to vacuum a large table I just got: > > postgres=# vacuum FREEZE ; > ERROR: invalid memory alloc request size 1073741828 > > #0 palloc (size=1073741828) at > /mnt/tools/src/postgresql/src/backend/utils/mmgr/mcxt.c:959 > #1 0x000056452cc45cac in lazy_space_alloc (vacrelstats=0x56452e5ab0e8, > vacrelstats=0x56452e5ab0e8, relblocks=24686152) > at /mnt/tools/src/postgresql/src/backend/access/heap/vacuumlazy.c:2741 > #2 lazy_scan_heap (aggressive=true, nindexes=1, Irel=0x56452e5ab1c8, > vacrelstats=<optimized out>, params=0x7ffdf8c00290, onerel=<optimized out>) > at /mnt/tools/src/postgresql/src/backend/access/heap/vacuumlazy.c:786 > #3 heap_vacuum_rel (onerel=<optimized out>, params=0x7ffdf8c00290, > bstrategy=<optimized out>) > at /mnt/tools/src/postgresql/src/backend/access/heap/vacuumlazy.c:472 > #4 0x000056452cd8b42c in table_relation_vacuum (bstrategy=<optimized out>, > params=0x7ffdf8c00290, rel=0x7fbcdff1e248) > at /mnt/tools/src/postgresql/src/include/access/tableam.h:1450 > #5 vacuum_rel (relid=16454, relation=<optimized out>, > params=params@entry=0x7ffdf8c00290) at > /mnt/tools/src/postgresql/src/backend/commands/vacuum.c:1882 > > Looks to me that the calculation moved into compute_max_dead_tuples() > continues to use use an allocation ceiling > maxtuples = Min(maxtuples, MaxAllocSize / > sizeof(ItemPointerData)); > but the actual allocation now is > > #define SizeOfLVDeadTuples(cnt) \ > add_size((offsetof(LVDeadTuples, itemptrs)), \ > mul_size(sizeof(ItemPointerData), cnt)) > > i.e. the overhead of offsetof(LVDeadTuples, itemptrs) is not taken into > account. >
Right, I think we need to take into account in both the places in compute_max_dead_tuples(): maxtuples = (vac_work_mem * 1024L) / sizeof(ItemPointerData); .. maxtuples = Min(maxtuples, MaxAllocSize / sizeof(ItemPointerData)); -- With Regards, Amit Kapila. EnterpriseDB: http://www.enterprisedb.com
