Re: [sqlite] Is it possible to change "synchronous" flag of ZIPVFS pager?

2017-03-17 Thread Tomasz Maj 
Thank you very much. You're super quick guys :)


Cheers,

Tomasz M


From: sqlite-users  on behalf of 
Dan Kennedy 
Sent: Thursday, March 16, 2017 8:34:30 PM
To: sqlite-users@mailinglists.sqlite.org
Subject: Re: [sqlite] Is it possible to change "synchronous" flag of ZIPVFS 
pager?

On 03/16/2017 05:00 PM, Tomasz Maj wrote:
> I have an application which work with many zipped databases in WAL journal 
> mode and the databases are stored on a media of low write bandwidth. There is 
> a problem that that fsync operations invoked from one thread are blocking 
> other fsync operations invoked from another thread. I think that changing the 
> synchronous mode to NORMAL on some connections may make the blocking issue 
> less painful. May the possibility of changing ZIPVFS synchronous mode be 
> implemented in sqlite?

Latest commit in the zipvfs project fixes things so that "PRAGMA
synchronous" works with zipvfs databases.

Dan.



>
>
> Cheers,
>
> Tomasz M
>
> 
> From: sqlite-users  on behalf 
> of Tomek Maj 
> Sent: Thursday, March 16, 2017 10:50:37 AM
> To: SQLite mailing list
> Subject: Re: [sqlite] Is it possible to change "synchronous" flag of ZIPVFS 
> pager?
>
> 2017-03-16 9:51 GMT+01:00 Dan Kennedy :
>
>> On 03/16/2017 01:40 PM, Tomasz Maj wrote:
>>
>>> Hi,
>>>
>>>
>>> According to my observations, "PRAGMA synchronous=...;" query affects
>>> only the standard sqlite pager. But for zipped databases sqlite uses
>>> additional ZIPVFS pager layer which actually decide whether and when to
>>> sync content of files associated with a database. It looks like "PRAGMA
>>> synchronous=...;" query doesn't have any effect on zipped databases. Are my
>>> observations right? If so, is it possible to manipulate "synchronous" flag
>>> of ZIPVFS pager?
>>>
>> It looks like there is not. Is it something you need to do?
>>
>> Dan.
>>
>>
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Re: [sqlite] Is it possible to change "synchronous" flag of ZIPVFS pager?

2017-03-16 Thread Dan Kennedy 

On 03/16/2017 05:00 PM, Tomasz Maj wrote:

I have an application which work with many zipped databases in WAL journal mode 
and the databases are stored on a media of low write bandwidth. There is a 
problem that that fsync operations invoked from one thread are blocking other 
fsync operations invoked from another thread. I think that changing the 
synchronous mode to NORMAL on some connections may make the blocking issue less 
painful. May the possibility of changing ZIPVFS synchronous mode be implemented 
in sqlite?


Latest commit in the zipvfs project fixes things so that "PRAGMA 
synchronous" works with zipvfs databases.


Dan.






Cheers,

Tomasz M


From: sqlite-users  on behalf of Tomek 
Maj 
Sent: Thursday, March 16, 2017 10:50:37 AM
To: SQLite mailing list
Subject: Re: [sqlite] Is it possible to change "synchronous" flag of ZIPVFS 
pager?

2017-03-16 9:51 GMT+01:00 Dan Kennedy :


On 03/16/2017 01:40 PM, Tomasz Maj wrote:


Hi,


According to my observations, "PRAGMA synchronous=...;" query affects
only the standard sqlite pager. But for zipped databases sqlite uses
additional ZIPVFS pager layer which actually decide whether and when to
sync content of files associated with a database. It looks like "PRAGMA
synchronous=...;" query doesn't have any effect on zipped databases. Are my
observations right? If so, is it possible to manipulate "synchronous" flag
of ZIPVFS pager?


It looks like there is not. Is it something you need to do?

Dan.


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Re: [sqlite] Is it possible to change "synchronous" flag of ZIPVFS pager?

2017-03-16 Thread Tomasz Maj 
I have an application which work with many zipped databases in WAL journal mode 
and the databases are stored on a media of low write bandwidth. There is a 
problem that that fsync operations invoked from one thread are blocking other 
fsync operations invoked from another thread. I think that changing the 
synchronous mode to NORMAL on some connections may make the blocking issue less 
painful. May the possibility of changing ZIPVFS synchronous mode be implemented 
in sqlite?


Cheers,

Tomasz M


From: sqlite-users  on behalf of 
Tomek Maj 
Sent: Thursday, March 16, 2017 10:50:37 AM
To: SQLite mailing list
Subject: Re: [sqlite] Is it possible to change "synchronous" flag of ZIPVFS 
pager?

2017-03-16 9:51 GMT+01:00 Dan Kennedy :

> On 03/16/2017 01:40 PM, Tomasz Maj wrote:
>
>> Hi,
>>
>>
>> According to my observations, "PRAGMA synchronous=...;" query affects
>> only the standard sqlite pager. But for zipped databases sqlite uses
>> additional ZIPVFS pager layer which actually decide whether and when to
>> sync content of files associated with a database. It looks like "PRAGMA
>> synchronous=...;" query doesn't have any effect on zipped databases. Are my
>> observations right? If so, is it possible to manipulate "synchronous" flag
>> of ZIPVFS pager?
>>
>
> It looks like there is not. Is it something you need to do?
>
> Dan.
>
>
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>
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Re: [sqlite] Is it possible to change "synchronous" flag of ZIPVFS pager?

2017-03-16 Thread Tomek Maj 
2017-03-16 9:51 GMT+01:00 Dan Kennedy :

> On 03/16/2017 01:40 PM, Tomasz Maj wrote:
>
>> Hi,
>>
>>
>> According to my observations, "PRAGMA synchronous=...;" query affects
>> only the standard sqlite pager. But for zipped databases sqlite uses
>> additional ZIPVFS pager layer which actually decide whether and when to
>> sync content of files associated with a database. It looks like "PRAGMA
>> synchronous=...;" query doesn't have any effect on zipped databases. Are my
>> observations right? If so, is it possible to manipulate "synchronous" flag
>> of ZIPVFS pager?
>>
>
> It looks like there is not. Is it something you need to do?
>
> Dan.
>
>
> ___
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> sqlite-users@mailinglists.sqlite.org
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Re: [sqlite] Is it possible to change "synchronous" flag of ZIPVFS pager?

2017-03-16 Thread Dan Kennedy 

On 03/16/2017 01:40 PM, Tomasz Maj wrote:

Hi,


According to my observations, "PRAGMA synchronous=...;" query affects only the standard sqlite 
pager. But for zipped databases sqlite uses additional ZIPVFS pager layer which actually decide whether and 
when to sync content of files associated with a database. It looks like "PRAGMA synchronous=...;" 
query doesn't have any effect on zipped databases. Are my observations right? If so, is it possible to 
manipulate "synchronous" flag of ZIPVFS pager?


It looks like there is not. Is it something you need to do?

Dan.

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[sqlite] Is it possible to change "synchronous" flag of ZIPVFS pager?

2017-03-16 Thread Tomasz Maj 
Hi,


According to my observations, "PRAGMA synchronous=...;" query affects only the 
standard sqlite pager. But for zipped databases sqlite uses additional ZIPVFS 
pager layer which actually decide whether and when to sync content of files 
associated with a database. It looks like "PRAGMA synchronous=...;" query 
doesn't have any effect on zipped databases. Are my observations right? If so, 
is it possible to manipulate "synchronous" flag of ZIPVFS pager?


Cheers,

Tomasz M

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