Re: [h2] SHUTDOWN COMPACT does not recover space SHUTDOWN DEFRAG take insanely long Opening DB takes 500Mb of space

[Petr Holík | EgoPanda]

Hello Thomas,

it makes a sense we are using CLOBs in our database extensively. And it
often ends with Missing LOB entry(which i've reported on github) or
database with wasted space (after deleting data mostly from table which
contains CLOBs). Propably is something broken in H2 in handling (C)LOB. We
have customers the that ends up with databases which contains multiple rows
with same unique constraint we have even databases with same(duplicate)
primary key(maybe it is fixed now, I don't know) but we can hardly make a
test case if customer is using this database daily for 3 years.
But missing LOB appears even in 1.4.192. Last month we have 3 issue on this.

I am sorry to say that, but we are now migrating to alternative embedded
java database. We are going to create some stress test and we will run it
against H2 too. If it ends with missing or non referenced LOB i'll let you
know.

Sincerely Petr Holik



2016-11-24 18:01 GMT+01:00 Thomas Mueller Graf :

> Hi,
>
> It could be due to LOG data (BLOB, CLOB) that are not referenced, and not
> correctly garbage collected. To analyze that, we would need a reproducible
> test case.
>
> To find out, you could use the Recover tool on the large database.
>
> Regards,
> Thomas
>
>
>
> On Tuesday, November 22, 2016, Petr Holík  wrote:
>
>> Hello,
>>
>>  1.4.192 db, Page Store  1.7GB -> SHUTDOWN COMPACT -> 1.4GB -> open ->
>> 1.9GB -> SHUTDOWN DEFRAG -> takes on cpu thread(3.5Ghz for maybe two three
>> minutes) -> SHUTDOWN COMPACT -> 1.4GB
>>
>> -> export to SQL ~60MB sql -> import -> ~60MB DB file
>>
>> Why compact does almost not compact and why opening db takes 500Mb of
>> space? I have not investigated ho much data process realy writes to db when
>> opening it.(on SSD it looks fast but on rotation disk it takes ages to open
>> DB)
>>
>> Sincerely Petr Holik
>>
>>
>>
>>
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>>
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-- 
S pozdravem Petr Holik
tel. 774 22 90 90

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Re: [h2] SHUTDOWN COMPACT does not recover space SHUTDOWN DEFRAG take insanely long Opening DB takes 500Mb of space

[Thomas Mueller Graf]

Hi,

It could be due to LOG data (BLOB, CLOB) that are not referenced, and not
correctly garbage collected. To analyze that, we would need a reproducible
test case.

To find out, you could use the Recover tool on the large database.

Regards,
Thomas



On Tuesday, November 22, 2016, Petr Holík  wrote:

> Hello,
>
>  1.4.192 db, Page Store  1.7GB -> SHUTDOWN COMPACT -> 1.4GB -> open ->
> 1.9GB -> SHUTDOWN DEFRAG -> takes on cpu thread(3.5Ghz for maybe two three
> minutes) -> SHUTDOWN COMPACT -> 1.4GB
>
> -> export to SQL ~60MB sql -> import -> ~60MB DB file
>
> Why compact does almost not compact and why opening db takes 500Mb of
> space? I have not investigated ho much data process realy writes to db when
> opening it.(on SSD it looks fast but on rotation disk it takes ages to open
> DB)
>
> Sincerely Petr Holik
>
>
>
>
> --
> You received this message because you are subscribed to the Google Groups
> "H2 Database" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to h2-database+unsubscr...@googlegroups.com
> 
> .
> To post to this group, send email to h2-database@googlegroups.com
> .
> Visit this group at https://groups.google.com/group/h2-database.
> For more options, visit https://groups.google.com/d/optout.
>

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Re: [h2] SHUTDOWN COMPACT does not recover space SHUTDOWN DEFRAG take insanely long Opening DB takes 500Mb of space

[Thomas Mueller Graf]

Hi,

It could be due to LOG data (BLOB, CLOB) that are not referenced, and not
correctly garbage collected. To analyze that, we would need a reproducible
test case.

To find out, you could use the Recover tool on the large database.

Regards,
Thomas



On Tuesday, November 22, 2016, Petr Holík  wrote:

> Hello,
>
>  1.4.192 db, Page Store  1.7GB -> SHUTDOWN COMPACT -> 1.4GB -> open ->
> 1.9GB -> SHUTDOWN DEFRAG -> takes on cpu thread(3.5Ghz for maybe two three
> minutes) -> SHUTDOWN COMPACT -> 1.4GB
>
> -> export to SQL ~60MB sql -> import -> ~60MB DB file
>
> Why compact does almost not compact and why opening db takes 500Mb of
> space? I have not investigated ho much data process realy writes to db when
> opening it.(on SSD it looks fast but on rotation disk it takes ages to open
> DB)
>
> Sincerely Petr Holik
>
>
>
>
> --
> You received this message because you are subscribed to the Google Groups
> "H2 Database" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to h2-database+unsubscr...@googlegroups.com
> 
> .
> To post to this group, send email to h2-database@googlegroups.com
> .
> Visit this group at https://groups.google.com/group/h2-database.
> For more options, visit https://groups.google.com/d/optout.
>

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