software.amazon.jdbc.plugin.readwritesplitting

Class AutoReadWriteSplittingPlugin

java.lang.Object

software.amazon.jdbc.plugin.AbstractConnectionPlugin

software.amazon.jdbc.plugin.readwritesplitting.AbstractReadWriteSplittingPlugin

software.amazon.jdbc.plugin.readwritesplitting.ReadWriteSplittingPlugin

software.amazon.jdbc.plugin.readwritesplitting.AutoReadWriteSplittingPlugin

All Implemented Interfaces:

CanReleaseResources, ConnectionPlugin, StateSnapshotProvider

public class AutoReadWriteSplittingPlugin
extends ReadWriteSplittingPlugin

Read/write splitting plugin that automatically routes queries based on SQL analysis. SELECT queries are routed to a reader instance; DML/DDL queries are routed to the writer. SELECT ... FOR UPDATE is detected and routed to the writer.

Routing can be overridden using SQL comment hints:

• /*@reader* / — force query to reader
• /*@writer* / — force query to writer
• /*@keep* / — run on the current connection without re-routing

Requires the sqlParser plugin to be loaded before this plugin. Connection routing is not changed while a transaction is in progress: a transaction keeps running against the connection it started on (so a read-only transaction started on a reader stays on the reader, and a write transaction stays on the writer).

Field Summary

Fields

Modifier and Type	Field and Description
static AwsWrapperProperty	LOAD_BALANCING_INCLUDE_WRITER
static AwsWrapperProperty	QUERY_LEVEL_LOAD_BALANCING

Fields inherited from class software.amazon.jdbc.plugin.readwritesplitting.ReadWriteSplittingPlugin

hosts, READER_HOST_SELECTOR_STRATEGY, readerSelectorStrategy, VERIFY_INITIAL_CONNECTION_ROLE, verifyInitialConnectionRole

Fields inherited from class software.amazon.jdbc.plugin.readwritesplitting.AbstractReadWriteSplittingPlugin

CACHED_READER_KEEP_ALIVE_TIMEOUT, hostListProviderService, inReadWriteSplit, isReaderConnFromInternalPool, isWriterConnFromInternalPool, pluginService, properties, readerCacheItem, readerHostSpec, writerConnection, writerHostSpec

Constructor Summary

Constructors

Constructor and Description
AutoReadWriteSplittingPlugin(PluginService pluginService, @NonNull java.util.Properties properties)

Method Summary

Modifier and Type	Method and Description
<T,E extends java.lang.Exception> T	execute(java.lang.Class<T> resultClass, java.lang.Class<E> exceptionClass, java.lang.Object methodInvokeOn, java.lang.String methodName, JdbcCallable<T,E> jdbcMethodFunc, java.lang.Object[] args)
java.util.Set<java.lang.String>	getSubscribedMethods()
void	releaseResources() An object that implements this interface should release all acquired resources assuming it may be disposed at any time.
protected void	switchToBalancedReader() Selects a balancing target for a read query and switches the current connection to it.

Methods inherited from class software.amazon.jdbc.plugin.readwritesplitting.ReadWriteSplittingPlugin

closeReaderIfNecessary, connect, getReaderHostCandidates, getSnapshotState, initializeReaderConnection, initializeWriterConnection, isReader, isWriter, openNewReaderConnection, refreshAndStoreTopology, shouldUpdateReaderConnection, shouldUpdateWriterConnection

Methods inherited from class software.amazon.jdbc.plugin.readwritesplitting.AbstractReadWriteSplittingPlugin

closeReaderConnectionIfIdle, closeWriterConnectionIfIdle, getKeepAliveTimeout, getReaderConnection, getReaderHostSpec, getWriterConnection, getWriterHostSpec, initHostProvider, isConnectionUsable, logAndThrowException, logAndThrowException, notifyConnectionChanged, setReaderConnection, setWriterConnection, switchConnectionIfRequired, switchCurrentConnectionTo

Methods inherited from class software.amazon.jdbc.plugin.AbstractConnectionPlugin

acceptsStrategy, forceConnect, getHostSpecByStrategy, getHostSpecByStrategy, notifyNodeListChanged

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

QUERY_LEVEL_LOAD_BALANCING

public static final AwsWrapperProperty QUERY_LEVEL_LOAD_BALANCING

LOAD_BALANCING_INCLUDE_WRITER

public static final AwsWrapperProperty LOAD_BALANCING_INCLUDE_WRITER

Constructor Detail

AutoReadWriteSplittingPlugin

public AutoReadWriteSplittingPlugin(PluginService pluginService,
                                    @NonNull java.util.Properties properties)

Method Detail

getSubscribedMethods

public java.util.Set<java.lang.String> getSubscribedMethods()

Specified by:

getSubscribedMethods in interface ConnectionPlugin

Overrides:

getSubscribedMethods in class AbstractReadWriteSplittingPlugin

execute

public <T,E extends java.lang.Exception> T execute(java.lang.Class<T> resultClass,
                                                   java.lang.Class<E> exceptionClass,
                                                   java.lang.Object methodInvokeOn,
                                                   java.lang.String methodName,
                                                   JdbcCallable<T,E> jdbcMethodFunc,
                                                   java.lang.Object[] args)
                                            throws E extends java.lang.Exception

Specified by:

execute in interface ConnectionPlugin

Overrides:

execute in class AbstractReadWriteSplittingPlugin

Throws:

E extends java.lang.Exception

switchToBalancedReader

protected void switchToBalancedReader()
                               throws java.sql.SQLException

Selects a balancing target for a read query and switches the current connection to it.

The target is chosen with the configured readerHostSelectorStrategy. When loadBalancingIncludeWriter is enabled, the writer instance is also eligible. If no eligible target is available, or the selected target is already the current host, the current connection is left in place. On connection failure the current connection is kept as a fallback when it is still usable.

This method is confined to the Automatic Read/Write Splitting Plugin and does not change the behavior of the other read/write splitting plugins.

Throws:

java.sql.SQLException

releaseResources

public void releaseResources()

Description copied from interface: CanReleaseResources

An object that implements this interface should release all acquired resources assuming it may be disposed at any time. This method may be called more than once.

Calling this method does NOT mean that an object is disposing and there won't be any further calls. An object should keep its functional state after calling this method.

Specified by:

releaseResources in interface CanReleaseResources

Overrides:

releaseResources in class AbstractReadWriteSplittingPlugin