Getting Startedwith pureQuery

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Getting Started with pureQuery
reducing the cache-hit rate. Having a large number of distinct statements that are
generated during runtime might also prevent you from being able to have your application
run all SQL statements statically, since it might not be feasible to capture every statement
that could execute.
6.10.2 How to use pureQuery SQL literal substitution
You can use the Client Optimizer to replace the literal values in SQL statements with
parameter markers, thereby potentially improving the security and performance of your
application. This is easy to do by setting a property, and it does not require changes to
your application.
To use the literal substitution feature for static or captured-only execution, you must set the
pureQuery property pdq.sqlLiteralSubstitution. This property can have one of
three values: ENABLE, DISABLE, and NOT_SET. NOT_SET is the default value. The
effects of the property depend on whether you are capturing to create a pureQueryXml file
or executing while specifying a pureQueryXml file. In general, use the value ENABLE if you
want to use literal substitution and the value DISABLE if you do not. The lists below
describe the specific meanings of the different values.
These are the effects of the different values during capture:
• ENABLE: pureQuery substitutes literal values with parameter markers in
as many of the statements that it captures as possible. pureQuery then
executes the parameterized versions of these statements instead of the
original versions. Consequently, the database and the JDBC driver are
only aware of their parameterized forms.
• DISABLE: pureQuery does not replace literal values; it captures SQL
statements how they are executed by the application. The maximum
number of SQL statements containing literals that pureQuery captures
can be limited by the value of the pureQuery property
pdq.maxNonParmSQL, if that property is set.
• NOT_SET: If the pureQueryXml file does not already exist, pureQuery
does not replace literal values. If the pureQueryXml already exists (which
means this is an incremental capture), pureQuery uses the value that was
set during the previous capture.
These are the effects of the different values when you specify a pureQueryXml file during
static or dynamic execution:
• ENABLE: pureQuery substitutes literal values with parameter markers in
the SQL statements that execute, and tries to match the statements to the
parameterized statements in the file. If pureQuery cannot find a matching
parameterized statement, pureQuery tries to match the original statement