my efforts are in C++-land using the default OS allocator (new/delete). I'm not using a garbage collector of any kind.
I has been my suspicion that the reason H2 isn't using a memory pool for Value is because Java is likely doing its own memory pool in its runtime and optimizing memory use dynamically based on usage patterns. -James On Apr 29, 2010, at 1:30 PM, Todd Stout wrote: > Sun's garbage collector has evolved such that an object cache can be harmful. > This was not true a long time ago, thus you can find dated articles talking > about the merits of using a cache. You probably should not assume that for > Sun's GC, a large number of small allocations will necessarily harm > performance. > > On Thu, Apr 29, 2010 at 1:56 PM, James Gregurich <[email protected]> wrote: > I've been putting a lot of thought into the value system since it would be > creating a lot of relatively small objects. I can see malloc/free being hit > hard by this mechanism in C++. > > Question: > > in the case of multiple, in-memory db's with multiple threads accessing them, > would it be useful to give each 'Session' or 'Database' its own Value object > cache? > > > Also, it seems to me (atleast in C++-land) that the 'Value' system to be a > good candidate to put on a memory pool rather than going through new/delete. > Any thoughts on that? > > -James > > On Apr 29, 2010, at 11:24 AM, Thomas Mueller wrote: > > > Hi, > > > >> I'm studying the Value object cache mechanism. I would appear to me that > >> multiple databases in one process would be sharing the static Value object > >> cache on multiple threads. What keeps access to this cache serialized? > > > > Nothing keeps it synchronized currently. A different thread will > > either see the old value, null, or the new value. This shouldn't be a > > problem. Updating references (pointers) in Java is not necessarily > > done in order, but it is atomic (otherwise it would be a security > > problem). > > > > Regards, > > Thomas > > > > -- > > 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. > > > > -- > 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. > > > > -- > 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. -- 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.
