ACTIVEMQ Persistence mode

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ACTIVEMQ Persistence

Message persistence should be a good way for reliable messaging, with message persistence, even if the sender and recipient are not at the same time online or the message center is down after the sender has sent the message and can still send the message after the message center restarts. If this persistence and reliablemessaging combination should be good to ensure the reliable transmission of the message.

The principle of message persistence is simple, that is, after the sender sends the message, the message center first stores the message to a local data file, a memory database, or a remote database, and then attempts to send the message to the receiver, the message is deleted from the store, and the failure continues to attempt. After the message center is started, first check the established storage location, if you have not sent a successful message, you need to send the message.

ACTIVEMQ Persistence mode: AMQ, kahadb, JDBC, LevelDB.

1, AMQ

AMQ is a form of file storage that has the characteristics of fast writing and easy recovery. The message is stored in a file, the default size of the file is 32M, and if the size of a message exceeds 32M, the value must be set larger. When a message in a stored file has all been consumed, then the file is identified as removable and the file is deleted during the next purge phase. AMQ applies to versions prior to ActiveMQ5.3 . The default configuration is as follows: [HTML] view plain copy print? <persistenceAdapter> <amqpersistenceadapter directory= "Activemq-data" maxfilelength= "32MB"/> </ Persistenceadapter>

The properties are as follows:

Property name	Default Value	Description
Directory	Activemq-data	Storage directory for message files and logs
Usenio	True	Storing messages using the NIO protocol
Synconwrite	False	Write to disk synchronously, this option has a very big impact on performance
Maxfilelength	32Mb	The size of a message file
Persistentindex	True	Persistence of the message index, if False, the index is saved in memory
Maxcheckpointmessageaddsize	4kb	Maximum number of messages allowed for a transaction
CleanupInterval	30000	Clear operation period, Unit MS
Indexbinsize	1024	Index file Cache page number, the default is 1024, when the AMQ expansion or reduction of storage, will lock the entire broker, resulting in a certain amount of time blocking, so this value should be adjusted to larger, but the code implementation will dynamically scale, the adjustment effect is not ideal.
Indexkeysize	96	Index key size, key is the message ID
Indexpagesize	16kb	Page size of the index
Directoryarchive	Archive	Store the archived message file directory
Archivedatalogs	False	When true, archived message files are moved to directoryarchive instead of being deleted directly

2, Kahadb

KAHADB is a file-based local database storage format, although not amq fast, but it has strong extensibility, recovery time is shorter than AMQ, since the 5.4 version of KAHADB as the default persistence mode. The default configuration is as follows: [HTML] view plain copy print? <persistenceAdapter> <kahadb directory= "Activemq-data" journalmaxfilelength= "32MB"/> </ Persistenceadapter>

The properties of the kahadb are as follows:

Property name	Default Value	Description
Directory	Activemq-data	Storage directory for message files and logs
Indexwritebatchsize	1000	The size of a batch of indexes that are updated to the message file when the index amount to be updated reaches this value
Indexcachesize	10000	In-memory, indexed page size
Enableindexwriteasync	False	Whether the index is asynchronously written to the message file
Journalmaxfilelength	32mb	The size of a message file
Enablejournaldisksyncs	True	Whether non-transactional messages are written to disk synchronously
CleanupInterval	30000	Clear operation period, Unit MS
Checkpointinterval	5000	The period in which the index is written to the message file, in units of MS
Ignoremissingjournalfiles	False	Ignore missing message file, False, start exception when message file is lost
Checkforcorruptjournalfiles	False	Check that the message file is corrupt, true, check for corruption and try to fix
Checksumjournalfiles	False	Generates a checksum to be able to detect if the journal file is corrupted.
Properties that are valid after version 5.4:
Archivedatalogs	False	When true, archived message files are moved to directoryarchive instead of being deleted directly
Directoryarchive	Null	Store the archived message file directory
Databaselockedwaitdelay	10000	Delay in waiting for file lock when using load, unit ms
Maxasyncjobs	10000	The same producer produces the largest number of asynchronous messages waiting to be written
Concurrentstoreanddispatchtopics	False	Whether to forward a topic message when writing a message
Concurrentstoreanddispatchqueues	True	Whether the queue message is forwarded when the message is written
Properties that are valid after version 5.6:
Archivecorruptedindex	False	Whether to archive the wrong index

Each instance of KAHADB can be configured with a separate adapter, and if no destination queue is submitted to filteredkahadb, it means that all queues are valid. If a queue does not have a corresponding adapter, an exception will be thrown. The configuration is as follows:[HTML] View Plain copy print? <persistenceAdapter>     <mkahadbdirectorymkahadbdirectory= "${activemq.base}/data/ Kahadb ">       <filteredPersistenceAdapters>          <!-- match all queues -->          <filteredkahadbqueuefilteredkahadbqueue= ">" >            <persistenceAdapter>              <kahadbjournalmaxfilelengthkahadbjournalmaxfilelength= "32MB"/>            </persistenceAdapter>         </ filteredkahadb>                  <!-- match all destinations -->         <filteredkahadb>           < persistenceadapter>             < Kahadbenablejournaldisksyncskahadbenablejournaldisksyncs= "false"/>            </persistenceAdapter>         </ filteredkahadb>       </filteredPersistenceAdapters>      </mKahaDB>   </persistenceAdapter>  

If the Perdestination property of FILTEREDKAHADB is set to true, then the matching target queue will get its own corresponding KAHADB instance. The configuration is as follows:[HTML] View Plain copy print? <persistenceAdapter>     <mkahadbdirectorymkahadbdirectory= "${activemq.base}/data/ Kahadb ">       <filteredPersistenceAdapters>          <!-- kahaDB per destinations -->          <filteredkahadb perdestination= "true" >            <persistenceAdapter>              <kahadbjournalmaxfilelengthkahadbjournalmaxfilelength= "32MB"  />            </persistenceAdapter>          </filteredKahaDB>       </filteredPersistenceAdapters>      </mKahaDB>   </persistenceAdapter>  

3. JDBC

Messages can be stored in a database, such as Mysql, SQL Server, Oracle, DB2.

Configure the JDBC adapter: [HTML] view plain copy print? <persistenceAdapter> <jdbcpersistenceadapterdatasourcejdbcpersistenceadapterdatasource= "#mysql-ds" Createtablesonstartup= "false"/> </persistenceAdapter>

DataSource Specifies whether the bean,createtablesonstartup of the persisted database creates a data table at startup, and the default value is true, so that every boot will create a data table, typically set to true the first time it is started, It is then changed to false.[HTML] View Plain copy print? MySQL persistence bean:   <bean id= "Mysql-ds"  class= "Org.apache.commons.dbcp.BasicDataSource"  destroy-method= "Close" >       <property name= "Driverclassname"  value= "Com.mysql.jdbc.Driver"/>       <property name= "url"   Value= "Jdbc:mysql://localhost/activemq?relaxautocommit=true"/>       < Property name= "username"  value= "activemq"/>       <property  Name= "Password"  value= "activemq"/>       <property name= " Poolpreparedstatements " value=" true "/>   </bean>   Sql server persisted bean:    <bean id= "Mssql-ds"  class= "Net.sourceforge.jtds.jdbcx.JtdsDataSource"   Destroy-method= "Close" >      <property name= "ServerName"  value= " SERVERNAME "/>      <property name= "PortNumber"  value= "PortNumber"/>      <property name= "DatabaseName"  value= "DatabaseName"/>       <property name= "User"  value= "user"/>      <property name = "Password"  value= "password"/>   </bean>   Oracle Persistence bean:   <bean  id= "Oracle-ds"  class= "Org.apache.commons.dbcp.BasicDataSource"  destroy-method= "Close" >        <property name= "Driverclassname"  value= " Oracle.jdbc.driver.OracleDriver "/>       <property name=" url "  Value= "Jdbc:oracle:thin:@10.53.132.47:1521:activemq"/>       <property  name= "username"  value= "activemq"/>       <property name= " Password " value=" ACTIVEMQ "/>       <property name= "maxactive"  value= "/>  "      <property name= "Poolpreparedstatements"  value= "true"/>   </bean >   DB2 Persistent bean:   <bean id= "Db2-ds"  class= " Org.apache.commons.dbcp.BasicDataSource "  destroy-method=" Close ">          <property name= "Driverclassname"  value= "Com.ibm.db2.jcc.DB2Driver"/>          <property name= "url"  value= "jdbc:db2:// Hndb02.bf.ctc.com:50002/activemq "/>         <property name=" Username " value=" activemq "/>         <property name=" Password " value=" Activemq "/>         <property name=