Fwd: Updates on large tables are extremely slow

From: Yves Vindevogel <yves(dot)vindevogel(at)implements(dot)be>
To: pgsql-performance(at)postgresql(dot)org
Subject: Fwd: Updates on large tables are extremely slow
Date: 2005-06-13 11:51:41
Message-ID: 554ac970b5cdc99527b01cac3dfbffa4@implements.be
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>
> I have started this on my testmachine at 11h20. It's still running
> and here it's 13h40.
>
> Setup:
> Intel P4 2Ghz, 1 Gb ram
> ReiserFS 3 (with atime in fstab, which is not optimal)
> Slackware 10
> PG 7.4
>
> I have the same problems on my OSX and other test machines.
>
> It's frustrating. Even Microsoft Access is faster !!
>
> On 13 Jun 2005, at 11:02, Yves Vindevogel wrote:
>
>> rvponp=# vacuum verbose tblPrintjobs ;
>> INFO: vacuuming "public.tblprintjobs"
>> INFO: index "pkprintjobs" now contains 622972 row versions in 8410
>> pages
>> DETAIL: 9526 index row versions were removed.
>> 0 index pages have been deleted, 0 are currently reusable.
>> CPU 0.60s/0.31u sec elapsed 31.68 sec.
>> INFO: index "uxprintjobs" now contains 622972 row versions in 3978
>> pages
>> DETAIL: 9526 index row versions were removed.
>> 0 index pages have been deleted, 0 are currently reusable.
>> CPU 0.15s/0.48u sec elapsed 3.59 sec.
>> INFO: index "ixprintjobsipaddress" now contains 622972 row versions
>> in 2542 pages
>> DETAIL: 9526 index row versions were removed.
>> 49 index pages have been deleted, 0 are currently reusable.
>> CPU 0.13s/0.24u sec elapsed 2.57 sec.
>> INFO: index "ixprintjobshostname" now contains 622972 row versions
>> in 2038 pages
>> DETAIL: 9526 index row versions were removed.
>> 35 index pages have been deleted, 0 are currently reusable.
>> CPU 0.09s/0.30u sec elapsed 1.14 sec.
>> INFO: index "ixprintjobsrecordnumber" now contains 622972 row
>> versions in 1850 pages
>> DETAIL: 9526 index row versions were removed.
>> 0 index pages have been deleted, 0 are currently reusable.
>> CPU 0.07s/0.28u sec elapsed 1.51 sec.
>> INFO: index "ixprintjobseventdate" now contains 622972 row versions
>> in 1408 pages
>> DETAIL: 9526 index row versions were removed.
>> 4 index pages have been deleted, 0 are currently reusable.
>> CPU 0.05s/0.24u sec elapsed 2.61 sec.
>> INFO: index "ixprintjobseventtime" now contains 622972 row versions
>> in 1711 pages
>> DETAIL: 9526 index row versions were removed.
>> 0 index pages have been deleted, 0 are currently reusable.
>> CPU 0.12s/0.53u sec elapsed 11.66 sec.
>> INFO: index "ixprintjobseventcomputer" now contains 622972 row
>> versions in 2039 pages
>> DETAIL: 9526 index row versions were removed.
>> 36 index pages have been deleted, 0 are currently reusable.
>> CPU 0.12s/0.23u sec elapsed 1.27 sec.
>> INFO: index "ixprintjobseventuser" now contains 622972 row versions
>> in 2523 pages
>> DETAIL: 9526 index row versions were removed.
>> 19 index pages have been deleted, 0 are currently reusable.
>> CPU 0.14s/0.24u sec elapsed 1.74 sec.
>> INFO: index "ixprintjobsloginuser" now contains 622972 row versions
>> in 2114 pages
>> DETAIL: 9526 index row versions were removed.
>> 13 index pages have been deleted, 0 are currently reusable.
>> CPU 0.07s/0.32u sec elapsed 4.29 sec.
>> INFO: index "ixprintjobsprintqueue" now contains 622972 row versions
>> in 2201 pages
>> DETAIL: 9526 index row versions were removed.
>> 30 index pages have been deleted, 0 are currently reusable.
>> CPU 0.10s/0.34u sec elapsed 1.92 sec.
>> INFO: index "ixprintjobsprintport" now contains 622972 row versions
>> in 3040 pages
>> DETAIL: 9526 index row versions were removed.
>> 40 index pages have been deleted, 0 are currently reusable.
>> CPU 0.18s/0.27u sec elapsed 2.63 sec.
>> INFO: index "ixprintjobssize" now contains 622972 row versions in
>> 1733 pages
>> DETAIL: 9526 index row versions were removed.
>> 0 index pages have been deleted, 0 are currently reusable.
>> CPU 0.16s/0.43u sec elapsed 4.07 sec.
>> INFO: index "ixprintjobspages" now contains 622972 row versions in
>> 1746 pages
>> DETAIL: 9526 index row versions were removed.
>> 24 index pages have been deleted, 0 are currently reusable.
>> CPU 0.13s/0.22u sec elapsed 1.58 sec.
>> INFO: index "ixprintjobsapplicationtype" now contains 622972 row
>> versions in 1395 pages
>> DETAIL: 9526 index row versions were removed.
>> 27 index pages have been deleted, 0 are currently reusable.
>> CPU 0.07s/0.29u sec elapsed 1.20 sec.
>> INFO: index "ixprintjobsusertype" now contains 622972 row versions
>> in 1393 pages
>> DETAIL: 9526 index row versions were removed.
>> 24 index pages have been deleted, 0 are currently reusable.
>> CPU 0.07s/0.22u sec elapsed 0.82 sec.
>> INFO: index "ixprintjobsdocumentname" now contains 622972 row
>> versions in 4539 pages
>> DETAIL: 9526 index row versions were removed.
>> 6 index pages have been deleted, 0 are currently reusable.
>> CPU 0.24s/0.38u sec elapsed 5.83 sec.
>> INFO: index "ixprintjobsdesceventdate" now contains 622972 row
>> versions in 1757 pages
>> DETAIL: 9526 index row versions were removed.
>> 4 index pages have been deleted, 0 are currently reusable.
>> CPU 0.08s/0.25u sec elapsed 1.16 sec.
>> INFO: index "ixprintjobsdesceventtime" now contains 622972 row
>> versions in 1711 pages
>> DETAIL: 9526 index row versions were removed.
>> 0 index pages have been deleted, 0 are currently reusable.
>> CPU 0.18s/0.52u sec elapsed 9.44 sec.
>> INFO: index "ixprintjobsdescpages" now contains 622972 row versions
>> in 1748 pages
>> DETAIL: 9526 index row versions were removed.
>> 24 index pages have been deleted, 0 are currently reusable.
>> CPU 0.06s/0.26u sec elapsed 0.94 sec.
>> INFO: index "ixprintjobspagesperjob" now contains 622972 row
>> versions in 5259 pages
>> DETAIL: 9526 index row versions were removed.
>> 4 index pages have been deleted, 0 are currently reusable.
>> CPU 0.31s/0.36u sec elapsed 5.47 sec.
>> INFO: "tblprintjobs": removed 9526 row versions in 307 pages
>> DETAIL: CPU 0.00s/0.06u sec elapsed 0.23 sec.
>> INFO: "tblprintjobs": found 9526 removable, 622972 nonremovable row
>> versions in 19382 pages
>> DETAIL: 0 dead row versions cannot be removed yet.
>> There were 75443 unused item pointers.
>> 0 pages are entirely empty.
>> CPU 3.43s/6.83u sec elapsed 97.86 sec.
>> INFO: vacuuming "pg_toast.pg_toast_2169880"
>> INFO: index "pg_toast_2169880_index" now contains 0 row versions in
>> 1 pages
>> DETAIL: 0 index pages have been deleted, 0 are currently reusable.
>> CPU 0.00s/0.00u sec elapsed 0.00 sec.
>> INFO: "pg_toast_2169880": found 0 removable, 0 nonremovable row
>> versions in 0 pages
>> DETAIL: 0 dead row versions cannot be removed yet.
>> There were 0 unused item pointers.
>> 0 pages are entirely empty.
>> CPU 0.00s/0.00u sec elapsed 0.00 sec.
>> VACUUM
>> rvponp=#
>>
>>
>>
>> On 13 Jun 2005, at 10:54, Mark Kirkwood wrote:
>>
>>> Apologies - I should have said output of 'VACUUM VERBOSE mytable'.
>>>
>>> (been using 8.1, which displays dead tuple info in ANALYZE...).
>>>
>>> Mark
>>>
>>> Yves Vindevogel wrote:
>>>> rvponp=# analyze verbose tblPrintjobs ;
>>>> INFO: analyzing "public.tblprintjobs"
>>>> INFO: "tblprintjobs": 19076 pages, 3000 rows sampled, 588209
>>>> estimated total rows
>>>> ANALYZE
>>>> On 13 Jun 2005, at 04:43, Mark Kirkwood wrote:
>>>> Yves Vindevogel wrote:
>>>> I'm trying to update a table that has about 600.000 records.
>>>> The update query is very simple : update mytable set
>>>> pagesdesc =
>>>> - pages ;
>>>> The query takes about half an hour to an hour to execute. I
>>>> have
>>>> tried a lot of things.
>>>> Half an hour seem a bit long - I would expect less than 5
>>>> minutes on
>>>> reasonable hardware.
>>>> You may have dead tuple bloat - can you post the output of
>>>> 'ANALYZE
>>>> VERBOSE mytable' ?
>>>
>>>
>> Met vriendelijke groeten,
>> Bien à vous,
>> Kind regards,
>>
>> Yves Vindevogel
>> Implements
>>
>> <Pasted Graphic 2.tiff>
>>
>> Mail: yves(dot)vindevogel(at)implements(dot)be - Mobile: +32 (478) 80 82 91
>>
>> Kempische Steenweg 206 - 3500 Hasselt - Tel-Fax: +32 (11) 43 55 76
>>
>> Web: http://www.implements.be
>>
>> First they ignore you. Then they laugh at you. Then they fight you.
>> Then you win.
>> Mahatma Ghandi.
>>
>>
>> ---------------------------(end of
>> broadcast)---------------------------
>> TIP 7: don't forget to increase your free space map settings
>>
> Met vriendelijke groeten,
> Bien à vous,
> Kind regards,
>
> Yves Vindevogel
> Implements
>

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