TIP, how to fight with corrupted indexing

[Ruslan Zasukhin]

on 2/4/03 12:23 PM, Robert Brenstein at rjb at rz.uni-potsdam.de wrote:

>> But how index can affect BLOB data?
>> I see only one way why it crashes. Record was deleted before crash. Yes?
>> 
>> Totte, may be you need add more Flushes after Updates()?
>> 
>>> PS, I have the database for you if you like.
>> 
> 
> Ruslan, I Flush after each database change but I definitely had data
> loss on a few ocassions (yes, data was entered into db but was not
> there after crash). I recon that Flush cleans the caches of Valentina
> but the operating system has its own write cache that may prevent the
> data to be actually written to disk before the crash.

No, Flush() at first write from Valentina cache,
Then calls system flush() to force data be written on disk.

> I have reduced 
> the system cache by an order of magnitude but (fortunately) I had no
> crashes lately to test the effect. But I wonder whether this might be
> a factor in at least some cases of problems with index files. There
> is clearly a need for a mechanism that ensures that indexes are in
> sync with data.

Yes, such mechanism will be so called TIMESTAMP -- internal time of
database. Each time is changed at least one field, value of tine is
incremented.

In 2.0 TIMESTAMP will present in each table in any case, for each record.
Because this is needed for our transaction model.

-- 
Best regards,
Ruslan Zasukhin      [ I feel the need...the need for speed ]
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e-mail: ruslan at paradigmasoft.com
web: http://www.paradigmasoft.com

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