MariaDB Connector/J 3.0.3 Release Notes

Note: This page describes features in an unreleased version of MariaDB Connector/J.

Unreleased means there are no official packages or binaries available for download which contain the features. The source code is available on GitHub.

MariaDB Connector/J 3.0.3 is a Stable (GA) release.

NOTE: MariaDB Connector/J 3.0.3 is NOT fully compatible with the latest release of version 2.7.

For an overview of MariaDB Connector/J see the About MariaDB Connector/J page

New version 3.0 is a complete rewrite of the connector, with code simplification, reduced size (15%), more than 90% coverage tested, with performance gain.

Licence is still LGPL-2.1 or later with copyright to MariaDB Corporation AB only (2.x was a fork from Drizzle-JDBC - BSD licensed)

What’s new :

  • Binary prepare statement improvement
  • Support of new 10.6 metadata skip
  • Pipelining PREPARE
  • REDO failover transaction
  • Better java version support
  • New option `tcpKeepIdle`, `tcpKeepCount`, `tcpKeepInterval` for java 11+
  • Provide a full JPMS module descriptor
  • new option `restrictedAuth` to permit authentication plugin restriction
  • metadata queries performance improvement
  • Easy logging
  • Deprecated option removal
  • Support codec registry implementation

Performance

Other than features, connector permit significant performance improvements : Here are real world TPCC benchmarks results, comparing connector version 2.7.4 and 3.0.3



2

Binary prepare statement improvement

When using option `useServerPrepStmts`, the connector uses BINARY protocol, meaning executing PREPARE + EXECUTE commands.

Pipelining

Queries issued from the application are sent one by one to the server, waiting on the results of the first query before sending the next. Communication with the server follows this synchronous request-response messaging pattern.

When using binary protocol, a PREPARE command is issued (if not in cache) before executing an EXECUTE command.

For MariaDB server 10.2+, the connector will send an optimistic PREPARE + EXECUTE, sending queries one after another. EXECUTE command will be executed only if the PREPARE command succeeds. This avoids some network latency reading PREPARE result before sending EXECUTE command.

Support of new 10.6 metadata skip

10.6 Server with MDEV-19237 permit to avoid resending metadata when they haven’t changed. This concerns SQL commands that return a resultset, when using option `useServerPrepStmts`.

Now, the server will send metadata only if they have changed (DDL change for example). This avoids useless information transiting on the network and parsing those metadata.

Connector internal JMH Benchmark results, selecting one row of a 100 int column table :

multicol

REDO failover transaction

After a failover occurs, reconnection will be automatically done according to high-availability configuration. Even if implementation is now smaller and clearer, the result will be the same.

After reconnection, the connector might still throw an exception if the state is unsure. Failover on replica are transparent. This is different when the failover occurs during the execution of a query on a master server.

A new option `transactionReplay` permit to replay transactions : Most of the time, queries occur in transactions so redo transaction implementation will solve most of the failover cases transparently. Option is disabled by default. When enabled, all queries in a transaction are cached until transaction resolution. If a failover occurs, the driver will recreate a new connection and replay cache. There is a few limitations: When the last command was a "commit" sent to the server, an exception will be thrown, the driver cannot know the current state. application must have idempotent queries only (queries can be "replayable") If the transaction is too big (cache size limit set with new option `transactionReplaySize`), the driver won’t cache the transaction anymore, so a failover during that specific transaction will result in throwing an exception.

Better java version support

Driver uses Multi-Release JARs (MRJAR), to simultaneously contain implementations for different versions of java. This permit still supports Java 8, but provides solutions for higher versions of java.

Connector now provides a java 9 full module-info JPMS descriptor

Java 11 socket extended option TCP_KEEPIDLE, TCP_KEEPCOUNT and TCP_KEEPINTERVAL are now configurable with `tcpKeepIdle`, `tcpKeepCount`, `tcpKeepInterval` options respectively. (These options don't have any effect if using a java version lower than 11).

Authentication plugin restriction

A new option `restrictedAuth` permits to restrict authentication plugins. Example connection string `jdbc:mariadb:localhost/db?restrictedAuth=mysql_native_password,client_ed25519` will restrict plugin use of standard mysql_native_password and client_ed25519 only.

Metadata queries performance improvement

Metadata queries use of information_schema improvement for partial or exact matching, permitting faster results.

Easy logging

Logging can now be easily enabled at runtime, using slf4j if present, or fallback to JDK logger / console if not.

  • INFO level log connection error
  • DEBUG/FINE level log commands
  • TRACE/FINEST level log network exchanges

Option changed

Ssl configuration use now a new option `sslMode` to simplify configuration Possible value are :

New options

disableNo ssl (default)
trustEncryption only (no certificate and hostname validation) (DEVELOPMENT ONLY)
verify-caEncryption, certificates validation, BUT no hostname verification
verify-fullStandard SSL use: Encryption, certificate validation and hostname validation

This can still be done by 2.x options (useSsl, disableSslHostnameVerification, trustServerCertificate) for compatibility, but this is the preferred way.

Option removal

Even if connectors aim to be compatible with the 2.x version, there has been very few option removal since connection exists. This is now the time :

allowMasterDownConnectionIn master/replica setup, master must be up
assureReadOnlyconnectors now configure replica connection being read-only
autoReconnectdoesn’t have any sense now, better use high availability mode
cachePrepStmtsalways cache when using binary protocol
callableStmtCacheSizealways cache when using binary protocol
continueBatchOnError
createDatabaseIfNotExistremoved, database has to be created if set
enablePacketDebuglog are now set using standard logger
ensureSocketStateremoved, this was a debugging option
failOnReadOnlyone master must always be present when using master/replica setup
failoverLoopRetriesfailover number of attempts rely now only on retriesAllDown option
jdbcCompliantTruncationThe connector ensures STRICT_TRANS_TABLES is always set to follow JDBC expected truncation.
keyPassword
loadBalanceBlacklistTimeoutdenied lists are handled automatically, and if all servers are denied, the connector will reconnect using the denied servers. No need for these options anymore.
loglog are now set using standard logger
maximizeMysqlCompatibilityvery old option for old mysql connector compatibility
nullCatalogMeansCurrentwas to permit non JDBC behavior for compatibility with old version correction
passwordCharacterEncoding
pinGlobalTxToPhysicalConnection
prepStmtCacheSqlLimitforced to 8K value
profileSqllog are now set using standard logger
retriesAllDownnot compatible with new failover implementation
rewriteBatchedStatementsreplaced by use of faster batching implementation ( COM_STMT_BULK)
serverTimezone
sharedMemoryplugin removed
slowQueryThresholdNanos
staticGlobal
tcpNoDelayWho would want to disable NAGLE to have a slow connector
tcpRcvBuf
tcpSndBuf
trackSchemaAutomatically set
trustStoreUse java standard truststore or option serverSslCert to provide certificates.
trustStorePasswordSame than trustStore
trustStoreTypeSame than trustStore
useBatchMultiSendreplaced by use of faster batching implementation ( COM_STMT_BULK)
useBatchMultiSendNumberSee useBatchMultiSend
useFractionalSecondsserver are expected to support fractional seconds (all mariadb server support it, mysql since 5.6)
useLegacyDatetimeCode
useOldAliasMetadataBehaviorwas to permit non JDBC behavior for compatibility with old version correction
validConnectionTimeoutNo automatic validation done by connector, pool must validate connection, not connector having a thread for that

Specific support for aurora has been removed, since Issues were piling up without the community proposing any PR for them and without access for us to test those modifications.

Changelog

For a complete list of changes made in MariaDB Connector/J 3.0.2, with links to detailed information on each push, see the changelog.

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