It is hard to predict the cache size based on raw data size since there are a number of factors affecting it. The best practice is to use the sizing tool, ttSize, that ships as part of TimesTen. You need an installed copy of TimesTen to run the tool and it should be the same bittedness (32 or 64) as the system that you are sizing for in order to give accurate results.
You create an empty table (and associated indexes) in TimesTen with the same structure as the table to be cached. Then run the ttSize tool against this table and specify the expected number of rows for the table. The tool then calculates, based on the way in which TimesTen stores data/indexes and taking into account overheads etc., the amount of memory needed for the table and each index and reports these. Repeat for each table you want to cache and sum the results. This is really the only way to predict how much memory will be needed to cache a table in TimesTen.
No comments:
Post a Comment