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 --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
