| From: | Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> |
|---|---|
| To: | Andres Freund <andres(at)anarazel(dot)de> |
| Cc: | Mahendra Singh Thalor <mahi6run(at)gmail(dot)com>, Dilip Kumar <dilipbalaut(at)gmail(dot)com>, Masahiko Sawada <masahiko(dot)sawada(at)2ndquadrant(dot)com>, Amit Langote <langote_amit_f8(at)lab(dot)ntt(dot)co(dot)jp>, Claudio Freire <klaussfreire(at)gmail(dot)com>, David Steele <david(at)pgmasters(dot)net>, Haribabu Kommi <kommi(dot)haribabu(at)gmail(dot)com>, Kyotaro HORIGUCHI <horiguchi(dot)kyotaro(at)lab(dot)ntt(dot)co(dot)jp>, Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com>, Michael Paquier <michael(dot)paquier(at)gmail(dot)com>, Pavan Deolasee <pavan(dot)deolasee(at)gmail(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>, Robert Haas <robertmhaas(at)gmail(dot)com>, Sergei Kornilov <sk(at)zsrv(dot)org>, Simon Riggs <simon(at)2ndquadrant(dot)com>, Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com> |
| Subject: | Re: [HACKERS] Block level parallel vacuum |
| Date: | 2020-01-21 06:34:58 |
| Message-ID: | CAA4eK1+1=oKGtd9v4cD_F6AJLrLKUO+pUifne-+uxvkD0mCOSg@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Tue, Jan 21, 2020 at 11:30 AM Andres Freund <andres(at)anarazel(dot)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(at)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
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