Hi, Yes, a larger page size should help.
The header of the freed pages is zeroed out so that in case of a crash, the free pages can be easily re-used. It's unlikely the checkpoint can be easily improved I'm afraid. I'm working on a new storage engine, but it will take a while until this is available. Regards, Thomas On Tuesday, April 3, 2012, Noel Grandin wrote: > I can't be sure, but it looks like it's zero-ing out the header of a page, > so I would assume that it's a little necessary. > > you could try increasing the page size of your database, that might speed > up this operation. > > > On 2012-04-02 17:15, Steve McLeod wrote: > >> Hi Thomas, >> >> When running TRUNCATE TABLE on a large table, it is time-consuming. I've >> done some profiling of the H2 source, and found that a step in >> PageStore.checkpoint() that consumes one-third of the time needed for >> TRUNCATE TABLE. In my specific case it uses 69 seconds out of seconds for >> the whole TRUNCATE execution. >> >> This line is the one consuming the time: >> >> file.readFully(test, 0, 16); >> >> which is org.h2.store.PageStore.java: line 451 in the current SVN trunk. >> >> It is part of a process of zeroing freed pages on disk. I'm wondering if >> zeroing is an important part of the workings of the PageStore. Or is it for >> security reasons? If so, is this step something I could potentially make >> optional by introducing a "INSECURE_FREE" database option? >> >> I'm running on Mac OS X Lion, using an SSD drive. >> >> Regards, >> >> Steve McLeod >> >> >> >> -- >> You received this message because you are subscribed to the Google Groups >> "H2 Database" group. >> To view this discussion on the web visit https://groups.google.com/d/** >> msg/h2-database/-/KpuvExBPO2sJ<https://groups.google.com/d/msg/h2-database/-/KpuvExBPO2sJ> >> **. >> To post to this group, send email to [email protected]. >> To unsubscribe from this group, send email to >> [email protected]. >> For more options, visit this group at http://groups.google.com/** >> group/h2-database?hl=en<http://groups.google.com/group/h2-database?hl=en> >> . >> > > -- > You received this message because you are subscribed to the Google Groups > "H2 Database" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at http://groups.google.com/** > group/h2-database?hl=en <http://groups.google.com/group/h2-database?hl=en> > . > > -- You received this message because you are subscribed to the Google Groups "H2 Database" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/h2-database?hl=en.
