The database is indexed for most popular searches. Unfortunately, for technical reasons not all of the many possible searches can be made lightning fast. Retrieval from more than 100 million games can take a while sometimes. If you are looking for very specific data searching and downloading can become (too) slow or even time out. The good news is that you have a few options to speed things up when this happens.
Searching for player names, variants, date ranges, results, and/or ECO codes generally is very fast. Adding more restrictions (ratings, time controls etc) can slow things down. Try to stick with the "fast" search criteria whereever possible. It is very easy to import the result set (which is a file in PGN format with the games matching your search criteria) into a database of your choice. Chessbase Light, Chessbase Reader and Scid are good and free choices for this task. Once you have imported the search results into such a local database program you can easily filter the result set.
If you are interested in longer games, searching by variant for "standard" will be much faster than searching for a time control. Searching only for rated games is often unnecessary because the database contains only very few unrated games.
Help and Contact
Do you encounter problems retrieving exactly the games you want even when applying these hints? Is the current maximum of 5000 games per query download not enough for your needs? Do you want to do large scale research on the database? We will try and get you the data you need, just drop us an email to firstname.lastname@example.org