>> Recently we have started noticing problems at many of our customers
>> where the index on certain tables are either corrupted or inactive.
>> These are three different scenarios that we have and I hope you can give
>> me some info on what is causing this.
>> 1. Index's are in the inactive state.2. Index whose definition was
>> changed and also in inactive state.3. Indexes are active but the select
>> using that index was not returning any results but once we inactivate
>> and reactivate the indexes it starts to work properly.
>> We are using Firebird 1.5.5.4926 and IBO components. We do a background
>> process at night to inactivate and reactivate all indexes but this
>> hasn't really helped the cause. We have checked to make sure that no
>> person is playing with the database and causing this issue and its
>> something in the program or some other factor which is causing this
>> issue. We have checked the code around the tables where these problems
>> exist and couldn't find anything that could cause the problem.
>> I hope that some of you can let me know what to look for to fix this
>> issue.
>
> AFAIR, quite some index corruption issues have been fixed in the 2.x series.

If you need to stay at 1.5 as a short-term plan, you should at least
update to 1.5.6, because it has the following fixed:

http://tracker.firebirdsql.org/browse/CORE-1830

--
With regards,
Thomas Steinmaurer
http://www.upscene.com/