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Author Ultralite sd card fragmentation and speed
handheldmaster

2005-08-23, 1:23 pm


ULtralite 8.0.2 (4392), Appforge MobileVB 4 on Windows
Mobile 2003

Users report application becomes sluggish & slower with time
... the only current fix is to delete the udb file and then
everything becomes normal.

Have not seen any *extra* rows between the udb files before
and after.

Was wondering on how ultralite internal database engine
works with the sd card. Is is possible that the file gets
fragmented over time hence access becomes slower ... once we
delete the file and recreate the db is back in contiguous
file fragments ?

Any other suggestions ?
Tom Slee

2005-08-29, 11:23 am

handheldmaster wrote:
> ULtralite 8.0.2 (4392), Appforge MobileVB 4 on Windows
> Mobile 2003
>
> Users report application becomes sluggish & slower with time
> .. the only current fix is to delete the udb file and then
> everything becomes normal.
>
> Have not seen any *extra* rows between the udb files before
> and after.
>
> Was wondering on how ultralite internal database engine
> works with the sd card. Is is possible that the file gets
> fragmented over time hence access becomes slower ... once we
> delete the file and recreate the db is back in contiguous
> file fragments ?
>
> Any other suggestions ?


If a table is growing bigger and there are a lot of indexes on it, it is
possible that index maintenance would cause inserts to be slower as the
table gets bigger.

Tom Slee
Michael Thode

2005-08-29, 11:23 am

Can you quantify "sluggish & slower". How slow does it get?

What about the database filesizes? Does the file grow unexpectedly.

One issue that others have run into is incorrect usage of the stop
syncronization delete feature. This should only be used on tables that are
syncronized.

Mike

<handheldmaster> wrote in message
news:430b5f4d.121e.1681692777@sybase.com...
>
> ULtralite 8.0.2 (4392), Appforge MobileVB 4 on Windows
> Mobile 2003
>
> Users report application becomes sluggish & slower with time
> .. the only current fix is to delete the udb file and then
> everything becomes normal.
>
> Have not seen any *extra* rows between the udb files before
> and after.
>
> Was wondering on how ultralite internal database engine
> works with the sd card. Is is possible that the file gets
> fragmented over time hence access becomes slower ... once we
> delete the file and recreate the db is back in contiguous
> file fragments ?
>
> Any other suggestions ?



handheldmaster

2005-09-01, 11:23 am


> Can you quantify "sluggish & slower". How slow does it
> get?
>

Places where there are MoveFirst and then MoveNext to
navigate through records or user is inserting records, user
is updating records. So basically everything becomes
sluggish .. how slow .. a process that would take 4 secs
takes 7 secs (an example).

> What about the database filesizes? Does the file grow
> unexpectedly.
>

Not unexpectedly as user syncs daily after a few syncs
itself have noticed the database file size grow .. example:
2 MB file grown to 4 MB, 6 MB file grown to 19 MB. Upload
download statistics are inserting about 200-300 records and
updating 500 records per sync.

> One issue that others have run into is incorrect usage of
> the stop syncronization delete feature. This should only
> be used on tables that are syncronized.
>

Yes am using it correctly. Also have confirmed the record
counts are not increasing.
Michael Thode

2005-09-06, 1:23 pm

If the time taken in your example stabilizes at around 7 seconds, then the
code is probably running as it should. You might want to look at ways to
optimize your query to see if you can make it run faster.

Mike

<handheldmaster> wrote in message news:43171bd9.42b.1681692777@sybase.com...
>
> Places where there are MoveFirst and then MoveNext to
> navigate through records or user is inserting records, user
> is updating records. So basically everything becomes
> sluggish .. how slow .. a process that would take 4 secs
> takes 7 secs (an example).
>
> Not unexpectedly as user syncs daily after a few syncs
> itself have noticed the database file size grow .. example:
> 2 MB file grown to 4 MB, 6 MB file grown to 19 MB. Upload
> download statistics are inserting about 200-300 records and
> updating 500 records per sync.
>
> Yes am using it correctly. Also have confirmed the record
> counts are not increasing.



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