ActiveMQ -- JDBC Journal of persistent mechanism

about activemq Long term persistence , In the use of JDBC It is also recommended to use high-performance journal

Activemq Journal, Cache write technology is used , Greatly improved performance , because JDBC It takes time to write and read messages every time , If there is a large amount of message data , It will cause frequent library writing .

journal It will save the information produced by the producer to journal In file , When consumers consume quickly ,journal Messages in the file are not synchronized to DB Before , Consumers have already consumed 90% The news of , At this time , Just synchronize the rest 10% The news came to DB. If consumers spend slowly ,journal Files can be written in batches DB.

journal To configure

stay activemq.xml Modify configuration

Before jdbc Configuration of ：

 <persistenceAdapter>
     <jdbcPersistenceAdapter dataDirectory="activemq-data" useDatabaseLock="false" dataSource="#mysql-ds" createTablesOnStartup="true" />
</persistenceAdapter>

Change to ： add to journal To configure

 <persistenceFactory>
     <journalPersistenceAdapterFactory journalLogFiles="4" journalLogFileSize="32768" useJournal="true" useQuickJournal="true" dataDirectory="activemq-data" useDatabaseLock="false" dataSource="#mysql-ds" createTablesOnStartup="true" />
</persistenceFactory>

test

Start producer production message , Check the database again ,ACTIVEMMQ_MSGS No message will be written immediately , because journal The existence of , Need to wait for a while