Hi, > I will try to use the new feature "OPEN_NEW" option and H2 on memory > mode. If there are other options to boost H2 performance (LinkedTable > access)
Let me correct, I will use "embedded mode" not memory mode. Sincerely, On Oct 7, 2:00 pm, Toshiaki Takashima <[EMAIL PROTECTED]> wrote: > Hi, > > > So you have 3 databases? In what database(s) do you use the multi-threaded > > flag? > > Yes, I have 3 databases. > > > > 1. prepared 2 tables in two separated RDBMS. > > Those RDBMS's are commercial products (Oracle and other vendor's). > > > > 2. created Linked Table for the 2 tables above. > > And I prepared H2 database which have LinkedTable objects for the each > above. > > > No. The same linked table (actually the same connection) is never used > > concurrently. > > For your information, My stress test showed that the result of a > query to the LinkedTable on multiple access was sometimes wrong when > MULTI_THREADED was enabled. > > Anyway, Because the response time was shorten, I thought that Low > performance > on over 20 concurrent multiple queries to LinkedTable was caused by > multi thread handling of H2. Why does H2 slow suddenly over 20? > > Please give me your advice : > > As I have said, I want to use H2 as multi-RDBMS view system. So, > I will only execute "SELECT" query to H2 LinkedTable, not UPDATE > statement. > > In that context, I want to boost H2 performance under multiple access > environment. > > I will try to use the new feature "OPEN_NEW" option and H2 on memory > mode. If there are other options to boost H2 performance (LinkedTable > access) > on that premise, please let me know. > > Sincerely, > > On Oct 7, 2:51 am, "Thomas Mueller" <[EMAIL PROTECTED]> > wrote: > > > > > Hi, > > > > I tested as follows : > > > 1. prepared 2 tables in two separated RDBMS. > > > 2. created Linked Table for the 2 tables above. > > > So you have 3 databases? In what database(s) do you use the multi-threaded > > flag? > > > > 1. I think MULTI_THREADED mode enables multiple concurrent > > > DB connections to RDBMS which is referenced from LinkedTable. > > > Am I right? > > > No. The same linked table (actually the same connection) is never used > > concurrently. > > > > 2. According to the Manual, OPTIMIZED_REUSE_RESULTS option > > > is enabled by default. Does the OPTIMIZED_REUSE_RESULTS option > > > decrease the number of queries which are executed from LinkedTable? > > > This option is not related to linked > > table.http://www.h2database.com/html/grammar.html#setoptimizereuseresults > > The database can't know if the data in the linked database was > > changed, so it always have to re-run the query. > > > Regards, > > Thomas- Hide quoted text - > > - Show quoted text - --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
