This is a new Alpha development release, adding new features and fixing recently discovered bugs.
Functionality added or changed:
Incompatible Change:
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.
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).
We've also added server and client
prepareStatement()
methods that cover all of
the variants in the JDBC API.
Connection.serverPrepare(String)
has been
re-named to
Connection.serverPrepareStatement()
for
consistency with
Connection.clientPrepareStatement()
.
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.
Made it possible to retrieve prepared statement parameter
bindings (to be used in
StatementInterceptors
, primarily).
Externalized the descriptions of connection properties.
The data (and how it is 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.
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.
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.
Added experimental support for statement "interceptors" via the
com.mysql.jdbc.StatementInterceptor
interface, examples are in
com/mysql/jdbc/interceptors
.
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
.
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.
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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