On 2015-09-30 11:46 AM, Deepak Hegde wrote: > Hi All, > > I have a to copy entry from on database to another which have the > similar structure. > > So I am using the method of ATTACH the DB and INSERT statement to insert > the 200 entries at a time. > I have observed that as the entries in the copied database increases > event though I am inserting 200 entry only, time for insertion keeps on > increasing.//...
Hi Deepak - (Not related to Mr. Chopra I trust?) The time taken to insert rows into a database is a function of the database size with several factors adding to it. Firstly, you need to use transactions to make the inserts faster if you are going to do multiple inserts. Secondly, it will be much faster if you insert using a SELECT query (as you do), but it can be the actual SELECT that takes longer to execute since I assume the original/source DB would have grown too. See taht you have good index for fast querying on the source DB. The time taken to insert items into a database (with already many items in it) is mostly due to needing to expand the indices of the target DB. If you have no Index at all (though you will still likely have the hidden rowid index) then theoretically the database can grow without using much time. For every Index you add, the time taken to insert will go up because the DB has to add and re-organize the B-Tree used for every index (In the standard case). Some bit of time gets lost on the file-handling of large files once they grow significantly, but that is usually rather negligible compared to the Indexing factors. HTH, Ryan
