Geoff Howard wrote: > > > > To come to a conlusion I did a simple performance test: > > - Creating 10000 random keys (strings) where each character is a value > > between 0 and 9 > > - Hashing the 10000 values > > - Putting the strings into the cache (a HashMap) > > - Putting the Hashed values into another cache (a HashMap) > > - Searching for all values in the string cache > I guess you mean for each value (in a loop)?
Exactly. > > > - Searching for all values in the hashed cache (this requires > > of course > > rehashing the values) > > > > And this is the result: > > Start key generation > > Created 10000 strings with average length 169 > OK, > > Start hashing > > Hashed: 120 ms > 120 for all 10,000 -> The hashing function takes .012 ms per call > on average Yes. > > > Creating cache with Strings > > Created: 60 ms > 60 ms for all 10,000 -> .006 ms on average Yes, this means all 10,000 strings are put into the hash map > > Creating cache with longs > > Created: 30 ms > same, .003 ms for longs (faster) Yes. > > Testing strings > > Strings: 10 ms > Object = mapWithStrings.get(KeyString) -> 10 ms for all 10000? -> .001 ms > per lookup average? (wow) Yupp. > > Testing hashed strings > > Hashed strings: 131 ms > Object = mapWithHashes.get(hashCreate(KeyString)) -> 131 ms for > all -> .0131 > ms per lookup average. Yes. > > > > > So, looking up the hashed information is slower as the values > > have to be > > rehashed. But > > putting strings into the cache is slower. > But putting strings in only takes twice the time -- taking them out is ten > times faster and happens more often (right?) Should be, yes. > > > From the test above it seems that using strings is still a > > little bit faster > > than > > using hashed values. > > Or did I oversee something? > I had been assuming that if the keys were not objects (strings) > but integers > that there could be a better datastructure than HashMap. I > haven't had much > time to think about it today but will tonight. Any ideas? In general this is right, but not for the cocoon caching. The tests I did are for one part of the compound key. I wanted to know if it is faster to use a string or a hashed value for this one part. The complete cache key is constructed from several parts, so this can never be a simple number. Carsten --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, email: [EMAIL PROTECTED]
