At 09:20 PM 27/03/2009, you wrote:

>I m sorry to have missed out on the complete information about the error, actually the error said
>' "I/O error for file "/full/path/ to/database. fdb" reached the End of file'

It means that you have run out of disk space...

>this error gets corrected if i do a back up and restore,

If the restore completed successfully then you were lucky...this time. You are now living on borrowed time. You should stop using the database immediately and make the necessary hardware changes to make more space available. You will run out of disk space again as garbage builds up.

>but i still couldn't find the reason for this error.

Now we know. But check also the file system of the partition where the database is. On FAT32 partitions you cannot grow a file larger than 2 GB. On older NTFS partitions the limit is 4GB. So if you think you have plenty of disk space available, then you can address the filesystem limits by adding secondary files to the database. DO THIS WHEN NOBODY IS ONLINE.

>the query that gives this error is of this form 'Select Column1,Column2 from Table1,Table2 where Condition order by orderedcol'

This will suffer from insufficient disk space too. The engine must have plenty of space to store its sort tables when there is insufficient RAM for it to create them in memory.

./heLen