About Cache


Replication error on slave restart

I'm trying to enable replication on master server that was running with "recovery" enabled previously. I have copied database file to slave... and so on by manual. It worked fine. But if I restart slave server: ... = "true" /> <processing cache = "64mb" max-threads = "8" /> <query-cache results = "32mb" programs = "500" /> ... "false" reflection = "warning" /> <cache ref = "weak" level2 = "0" /> <persist ...



... Fixed the behavior of CacheStoreMode setting in L2 shared cache. Fixed  TreeSet and TreeMap  element ... in a new ancestor class. Fixed a query cache bug. Fixed several bugs in query processing and running. ...


Threaded Test - Failed to commit transaction: Unexpected internal exception

Hi I'm trying to create a simple producer-consumer queue scenario but am getting the followin exception: ... to fixed size of 100 bytes, keeping much more results in cache than allowed by the defined cache size. Please try build 2.2.7_02 that should fix it. About the ...


Performance tuning, best practices

we have a system where we serve from a host process around 200 clients connected via webSockets (Jetty). The core process is running on a dedicated Windows 2012 server with 16 GByte RAM and 8 processor cores.  What is strange for us is that max 20% of the cpu resources are used and the IO subsystem is at maximum 30% of activity under heavy load but database queries are let's say not at the speed we would expect. We have currently 20.000.000 objects in the database, our configuration settings are: ... version-check="true" />   <processing cache="2048mb" max-threads="48" /> ... enabled="true" priority="40" />   <query-cache results="1024mb" programs="500" />   <extensions ... agent="false" reflection="warning" />   <cache ref="weak" level2="2048mb" /> ...


Setting and Tuning of JPA Queries

Explains various JPA query settings - result range, flush and lock.... no content). This could be useful when the shared L2 cache is enabled and entity objects may already be available in the cache. Setting Query Hint (Scopes) Query hints can be set ...


Internal exception when quering

Hello, following exception occurs when quering objectdb: ... JpaQuery. java : 686 ) at com. ysoft . cache . objectdb . ObjectCacheDB . search ( ObjectCacheDB. java : 522 ) at com. ysoft . cache . objectdb . ObjectCacheDB . search ( ObjectCacheDB. java ...


Performance Questions...

Greetings ObjectDB team, All below questions assume a very large database (~1,000,000,000 objects) Q1: Two queries with a big overlap between their result sets. If I query the first and hold them in memory somehow, would that speed up the execution of the second query since many of its result objects already created and reside in memory ? Q2: Do I need to manually use strong references to such cached result objects ? or do ObjectDB exploits frequency of querying such objects and keep them in memory longer automatically somehow before GC takes place ?... of the EntityManager's persistence context (L1) cache. But otherwise read only databases are not faster. Future versions of ObjectDB might share an L1 cache of read only entity managers automatically. Even though ObjectDB ...


Monitoring and Performance counters

After checking last patch from build 2.1.1_01, I started to think about some kind o monitoring tools in ODB. Those tools could look similar to MySQL 'show innodb status', where you can get some informations about how DB is doing. It would be nice to monitor: - inserts/s, updates/s, deletes/s, reads/s - total inserts, update, deletes, reads - I/O operations/s - caches current usage - uptime from last start - caches hit rate - total sessions from clients Feature Request Version: 2.5.2 Priority: Normal Status: Active Replies: 2 Type:  Feature Request ...



The JDO Transaction interface provides for initiation and completion of transactions under user control.(Interface of JDO)



Annotation for defining the persistence of a member.(Annotation of JDO)