>On 22/07/2025 07:53, Mark Thomas wrote: >>On 21/07/2025 17:48, Daniel Sheridan wrote: >>> On 18/07/2025 16:04, Daniel Sheridan wrote: >>> >>>> I definitely think there is something happening on the Tomcat side here >>>> around caching, I've played with some resource caching settings but it >>>> didn't make any difference unfortunately. >>> >>> The flame graph is showing that Tomcat is having to reload the JAR indexes >>> that it uses to find files in JARs (so Tomcat doesn't have to search >>> through every JAR every time it needs to load a new class). >>> >>> That index gets removed (to reduce memory footprint) periodically if it >>> isn't being used. By default this check happens every 10 seconds. >>> >>> To speed things up try experimenting with the archiveIndexStrategy of the >>> Resources element. I suspect you'll want to use "bloom". You will likely >>> see a larger memory footprint but you should also see less (no?) delays. >>> >>> Mark >>> >>> >>> --------------------------------------------------------------------- >>> To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org >>> For additional commands, e-mail: users-h...@tomcat.apache.org >>> >>> >> >> Hi Mark, >> >> I've tried this out and after some initial testing I am seeing improvements! >> I'll be doing some more extensive testing this week, but I'm not seeing the >> delay so far. >> >> On monitoring I don't see any noticeable increase in memory usage so far, >> but that would be somewhat of a concern if increased memory usage is >> possible. Would you have any idea of how much of a potential memory increase >> moving from the default setting to bloom could cause, and if it would be >> just in the short term until the indexes are eventually removed? > >Memory usage will be <1kB per JAR file. So for most web applications that will >be in the noise. In your case, you'd be looking at less than 200kB. > >With "bloom" the indexes are never removed so the memory is used until the web >application stops. > >> I assume that the bloom filter has a longer interval between the index >> checking like you described, so the indexes aren't removed as often? > >There is the option to use "purged" which will clear out the bloom filters >regularly. The check is every 10s by default and if a JAR is not being used, >the corresponding bloom filter is cleared. > >Given the low memory usage and associated performance benefits, I think there >is a case for making "bloom" the default for Tomcat 12 onwards. > >Mark > >--------------------------------------------------------------------- >To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org >For additional commands, e-mail: users-h...@tomcat.apache.org
Hi Mark, Alright, it sounds like the 'bloom' option is the way to go so. I'll keep testing it out, but it's looking good for us so far. Really appreciate your input on this! - Dan
