Database open slow? [WORKAROUND] (Ruslan Zasukhin)

[Leo Van den Brande]

>>>

Hi Tom and Ruslan,

>>> I realized, that it takes sometimes minutes just for a simple
>>> vdatabase.open(fileame).
>>> Sometimes it takes minutes for a vdatabse.close.
>>> Specially after a restart of the pc.
>>
>> After restart, on WINDOWS -- this is known issue
>> Present in Mantis.
>>
>> On MAC and Linux there is no such behavior.
>> On this list was a couple threads about this.
>>
>>
>>> The files are big, 500mb. I also have a big cache, 100MB. Can this  
>>> be a
>>> reason?
>>
>> Yes, both.
>>
>>> The databases are ok, (utf16 :-), no problems in diagnose, and  
>>> once they are
>>> open, speed is normal.
>>
>> We do not know yet exactly how resolve this.
>>
>> May be to use lazy memory allocation.
>> I am not sure it present on windows.
>>
>> May be Defragmenttion of db will help somehow..
>
> You are writing into the files, even the timestamp is modified.
>
> So what helps as a workaround is setting the readonly-flag on the  
> database files.
> Then the dbs are opened immediately.
> For me its ok, since I'm anyway only reading from the dbs.

This is great, Tom. I checked and even a large DB (1.6 Gb) opens  
within 2-3 seconds. With the help of Ruslan I already had reduced  
opening times after restart of Windows to an acceptable level by  
moving from v3 to v4 and reducing the number of tables in the version  
for students, So, for the students version of my DB,  your workaround  
is perfect and I will use it for the distribution of my present  
project (an interactive and multimedial clinical textbook on  
pediatrics).

In my case there also is an authors version which obviously must be  
read-write and for which a reduction of tables is not in order. For my  
present project I can accept the slowness since entering data in the  
DB is done by myself and one other person, both having sufficient  
patience. However, before making my program and DB available to  
authors and editors of new projects I'm waiting for a solution by  
Ruslan and his crew. At present, DB-opening times on Windows for these  
large DBs are just too long.

Leo






>
>
>
> On 6/9/09 11:07 PM, "Thomas Flemming" <tf at ttqv.com> wrote:
>
>>> May be Defragmenttion of db will help somehow..
>>
>> You are writing into the files, even the timestamp is modified.
>
> Well, at least we write one flag that db file is open now..
> If I remember right.
>
>> So what helps as a workaround is setting the readonly-flag on the  
>> database
>> files.
>> Then the dbs are opened immediately.
>> For me its ok, since I'm anyway only reading from the dbs.
>
> Very interesting ...
> Thank you for this observation.
>


Leo Van den Brande
J. Buziaulaan 61, Utrecht
(+31) (0)30 2511767
leo_van_den_brande at wxs.nl