Connector/J 5.1.1 Alpha Released

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Hi,=20

MySQL Connector/J 5.1.1 a new alpha version of the Type-IV pure-Java =
JDBC driver for MySQL has been released.=20

Version 5.1.1 is suitable for use with any MySQL version including =
MySQL-4.1, MySQL-5.0, MySQL-5.1 beta or the MySQL-5.2 Falcon "Preview".

It is now available in source and binary form from the Connector/J =
download pages at=20

http://dev.mysql.com/downloads/connector/j/5.1.html

and mirror sites (note that not all mirror sites may be up to date at =
this point of time - if you can't find this version on some mirror, =
please try again later or choose another download site.)

As always, we recommend that you check the change log

http://dev.mysql.com/doc/refman/5.0/en/cj-news.html=20

and "Upgrading" sections=20

http://dev.mysql.com/doc/refman/5.0/en/cj-upgrading.html=20

in the manual before upgrading as well as the "CHANGES" file in the =
download archive to be aware of changes in behavior that might affect =
your application.=20

We welcome and appreciate your feedback, bug reports, bug fixes, patches =
etc.:

http://forge.mysql.com/wiki/Contributing

This is the last alpha release of our implementation of the new JDBC-4.0 =
API, with a beta release planned to follow shortly based on feedback =
from this release.

This alpha release, as any other pre-production release, should not be =
installed on production level systems or systems with critical data. It =
is good practice to back up your data before installing any new version =
of software. Although MySQL has worked very hard to ensure a high level =
of quality, protect your data by making a backup as you would for any =
other software pre-production release.

MySQL Connector/J 5.1.1 includes the following new features compared to =
5.1.0:

* Pulled vendor-extension methods of Connection implementation out =
into an interface to support java.sql.Wrapper functionality from =
ConnectionPoolDataSource. The vendor extensions are javadoc'd in the =
com.mysql.jdbc.Connection interface.
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For those looking further into the driver implementation, it is not =
an API that is used for plugability of implementations inside our driver =
(which is why there are still references to ConnectionImpl throughout =
the code).
=20
Incompatible change: Connection.serverPrepare(String) has been =
re-named
to Connection.serverPrepareStatement() for consistency with=20
Connection.clientPrepareStatement().
=20
We've also added server and client prepareStatement() methods that =
cover all of the variants in the JDBC API.
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* Similar to Connection, we pulled out vendor extensions to Statement =
into an interface named "com.mysql.Statement", and moved the Statement =
class into com.mysql.StatementImpl. The two methods (javadoc'd in =
"com.mysql.Statement" are enableStreamingResults(), which already =
existed, and disableStreamingResults() which sets the statement =
instance back to the fetch size and result set type it had before =
enableStreamingResults() was called.
=20
* Added experimental support for statement "interceptors" via the =
com.mysql.jdbc.StatementInterceptor interface, examples are in =
com/mysql/jdbc/interceptors.
=20
Implement this interface to be placed "in between" query execution, =
so that you can influence it. (currently experimental).

StatementInterceptors are "chainable" when configured by the user, =
the results returned by the "current" interceptor will be passed on to =
the next on in the chain, from left-to-right order, as specified by the =
user in the JDBC configuration property "statementInterceptors".
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See the sources (fully javadoc'd) for =
com.mysql.jdbc.StatementInterceptor for more details until we iron out =
the API and get it documented in the manual.=20
=20
* Externalized the descriptions of connection properties.
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* The data (and how it's stored) for ResultSet rows are now behind an =
interface which allows us (in some cases) to allocate less memory per =
row, in that for "streaming" result sets, we re-use the packet used to =
read rows, since only one row at a time is ever active.
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* Made it possible to retrieve prepared statement parameter bindings =
(to be used in StatementInterceptors, primarily).=20
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* Row navigation now causes any streams/readers open on the result set =
to be closed, as in some cases we're reading directly from a shared =
network packet and it will be overwritten by the "next" row.
=20
* Setting "rewriteBatchedStatements" to "true" now causes =
CallableStatements with batched arguments to be re-written in the form =
"CALL (...); CALL (...); ..." to send the batch in as few client-server =
round trips as possible.
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* Driver now picks appropriate internal row representation (whole row =
in one buffer, or individual byte[]s for each column value) depending on =
heuristics, including whether or not the row has BLOB or TEXT types and =
the overall row-size. The threshold for row size that will cause the =
driver to use a buffer rather than individual byte[]s is configured by =
the configuration property "largeRowSizeThreshold", which has a default =
value of 2KB.

* When unpacking result set rows from result sets without TEXT or BLOB =
columns, the driver now avoids one copy and reads from the network =
directly, resulting in an approximate 3% performance increase for most =
workloads.

The following features are new, compared to the 5.0 series of =
Connector/J:

* JDBC-4.0 ease-of-development features including auto-registration =
with the DriverManager via the service provider mechanism, standardized =
Connection validity checks and categorized SQLExceptions based on =
recoverability/retry-ability and class of the underlying error.=20

* JDBC-4.0 standardized unwrapping to interfaces that include vendor =
extensions=20

* Support for JDBC-4.0 XML processing via JAXP interfaces to DOM, SAX =
and StAX=20

* JDBC-4.0 support for setting per-connection client information =
(which can be viewed in the comments section of a query via "SHOW =
PROCESSLIST" on a MySQL server, or can be extended to support custom =
persistence of the information via a public interface)=20

* Support for JDBC-4.0 NCHAR, NVARCHAR and NCLOB types=20

* The driver will automatically adjust the server session variable =
"net_write_timeout" when it determines its been asked for a "streaming" =
result, and resets it to the previous value when the result set has been =
consumed. (The configuration property is named =
"netTimeoutForStreamingResults", with a unit of seconds, the value '0' =
means the driver will not try and adjust this value).

This release also includes the following cahnges that are also present =
in Connector/J 5.0.7 (not yet released):

* Setting the configuration parameter "useCursorFetch" to "true" for =
MySQL-5.0+ enables the use of cursors that allow Connector/J to save =
memory by fetching result set rows in chunks (where the chunk size is =
set by calling setFetchSize() on a Statement or ResultSet) by using =
fully-materialized cursors on the server.=20
=20
The driver will will now automatically set "useServerPrepStmts" to =

"true" when "useCursorFetch" has been set to "true", since the =
feature=20
requires server-side prepared statements in order to function.
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* Fixed BUG#28469 - PreparedStatement.getMetaData() for statements =
containing leading one-line comments is not returned correctly.

As part of this fix, we also overhauled detection of DML for =
executeQuery() and SELECTs for executeUpdate() in plain and prepared =
statements to be aware of the same types of comments.

* Added configuration property "useNanosForElapsedTime" - for =
profiling/debugging functionality that measures elapsed time, should the =
driver try to use nanoseconds resolution if available (requires JDK =
>=3D 1.5)?
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* Added configuration property "slowQueryThresholdNanos" - if =
"useNanosForElapsedTime" is set to "true", and this property is set to a =
non-zero value the driver will use this threshold (in nanosecond =
units) to determine if a query was slow, instead of using millisecond =
units.
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Note, that if "useNanosForElapsedTime" is set to "true", and this =
property is set to "0" (or left default), then elapsed times will still =
be measured in nanoseconds (if possible), but the slow query threshold =
will be converted from milliseconds to nanoseconds, and thus have an =
upper bound of approximately 2000 millesconds (as that threshold is =
represented as an integer, not a long).
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* Added configuration properties to allow tuning of TCP/IP socket =
parameters:
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"tcpNoDelay" - Should the driver set SO_TCP_NODELAY (disabling the=20
Nagle Algorithm, default "true")?
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"tcpKeepAlive" - Should the driver set SO_KEEPALIVE (default "true")?
=09
"tcpRcvBuf" - Should the driver set SO_RCV_BUF to the given value?
The default value of '0', means use the platform default =

value for this property.
=09
"tcpSndBuf" - Should the driver set SO_SND_BUF to the given value?
The default value of '0', means use the platform default =

value for this property.
=09
"tcpTrafficClass" - Should the driver set traffic class or=20
type-of-service fields? See the documentation=20
for java.net.Socket.setTrafficClass() for more=20
information. =20

* Give more information in EOFExceptions thrown out of MysqlIO (how =
many bytes the driver expected to read, how many it actually read, say =
that communications with the server were unexpectedly lost).
=20
* Setting "useDynamicCharsetInfo" to "false" now causes driver to use =
static lookups for collations as well (makes =
ResultSetMetadata.isCaseSensitive() much more efficient, which leads to =
performance increase for ColdFusion, which calls this method for every =
column on every table it sees, it appears).
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* Driver detects when it is running in a ColdFusion MX server (tested =
with version 7), and uses the configuration bundle "coldFusion", which =
sets useDynamicCharsetInfo to "false" (see previous entry), and sets =
useLocalSessionState and autoReconnect to "true".Enjoy!

-Mark

- --=20
Mark Matthews, Architect (Client Connectivity)
MySQL, Inc. Chicago, USA - www.mysql.com
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