org.intermine.sql.precompute
Class BestQueryExplainer

java.lang.Object
  org.intermine.sql.precompute.BestQuery
      org.intermine.sql.precompute.BestQueryExplainer

Direct Known Subclasses:

BestQueryExplainerVerbose

public class BestQueryExplainer
extends BestQuery

Gets the database to explain each Query added and keeps hold of the best one so far.

Nested Class Summary

protected class

BestQueryExplainer.Candidate A class representing a candidate optimised query.

Field Summary

protected static int	ALWAYS_EXPLAIN_TABLES
protected BestQueryExplainer.Candidate	bestCandidate
protected java.util.List<BestQueryExplainer.Candidate>	candidates
protected int	candidateTables
protected java.sql.Connection	con
protected static int	NEVER_EXPLAIN_TABLES
protected java.util.Date	start
protected long	timeLimit

Constructor Summary

BestQueryExplainer()
Constructs an empty BestQueryExplainer for testing purposes

BestQueryExplainer(java.sql.Connection con, long timeLimit)
Constructs a BestQueryExplainer that will use the given Connection to explain Queries.

Method Summary

protected void	add(BestQueryExplainer.Candidate c) Allows a Candidate to be added to this tracker.
void	add(Query q) Allows a Query to be added to this tracker.
void	add(java.lang.String q) Allows a Query to be added to this tracker.
protected void	didNotExplain(BestQueryExplainer.Candidate c) Internal method that records that a query was not explained.
protected BestQueryExplainer.Candidate	getBest() Gets the best Candidate found so far.
ExplainResult	getBestExplainResult() Gets the ExpainResult for the best Query found so far.
Query	getBestQuery() Gets the best Query found so far
java.lang.String	getBestQueryString() Gets the best query String found so far.
protected ExplainResult	getExplainResult(Query q) Internal method that creates an ExplainResult.
protected ExplainResult	getExplainResult(java.lang.String q) Internal method that creates an ExplainResult.
void	throwBestQueryException(java.lang.String message) Throws an exception.

Methods inherited from class java.lang.Object

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

Field Detail

ALWAYS_EXPLAIN_TABLES

protected static final int ALWAYS_EXPLAIN_TABLES

See Also:

Constant Field Values

NEVER_EXPLAIN_TABLES

protected static final int NEVER_EXPLAIN_TABLES

See Also:

Constant Field Values

candidates

protected java.util.List<BestQueryExplainer.Candidate> candidates

candidateTables

protected int candidateTables

bestCandidate

protected BestQueryExplainer.Candidate bestCandidate

con

protected java.sql.Connection con

start

protected java.util.Date start

timeLimit

protected long timeLimit

Constructor Detail

BestQueryExplainer

public BestQueryExplainer()

Constructs an empty BestQueryExplainer for testing purposes

BestQueryExplainer

public BestQueryExplainer(java.sql.Connection con,
                          long timeLimit)

Constructs a BestQueryExplainer that will use the given Connection to explain Queries.

Parameters:

con - the Connection to use

timeLimit - a time limit in milliseconds

Method Detail

add

public void add(Query q)
         throws BestQueryException,
                java.sql.SQLException

Allows a Query to be added to this tracker.

Specified by:

add in class BestQuery

Parameters:

q - a Query to be added to the tracker

Throws:

BestQueryException - if the current best Query is the best we think we are going to get

java.sql.SQLException - if error occurs in the underlying database

add

public void add(java.lang.String q)
         throws BestQueryException,
                java.sql.SQLException

Allows a Query to be added to this tracker.

Specified by:

add in class BestQuery

Parameters:

q - a query String to be added to the tracker

Throws:

BestQueryException - if the current best Query is the best we think we are going to get

java.sql.SQLException - if error occurs in the underlying database

add

protected void add(BestQueryExplainer.Candidate c)
            throws BestQueryException,
                   java.sql.SQLException

Allows a Candidate to be added to this tracker.

Parameters:

c - the Candidate

Throws:

BestQueryException - if the current best Candidate is the best we think we are going to get

java.sql.SQLException - if an error occurs in the underlying database

getExplainResult

protected ExplainResult getExplainResult(Query q)
                                  throws java.sql.SQLException

Internal method that creates an ExplainResult. It can be overridden by subclasses.

Parameters:

q - the Query

Returns:

an ExplainResult

Throws:

java.sql.SQLException - if an error occurs in the underlying database

getExplainResult

protected ExplainResult getExplainResult(java.lang.String q)
                                  throws java.sql.SQLException

Internal method that creates an ExplainResult. It can be overridden by subclasses.

Parameters:

q - the query String

Returns:

an ExplainResult

Throws:

java.sql.SQLException - if an error occurs in the underlying database

didNotExplain

protected void didNotExplain(BestQueryExplainer.Candidate c)

Internal method that records that a query was not explained. It can be overridden by subclasses.

Parameters:

c - the Candidate

getBestQuery

public Query getBestQuery()
                   throws java.sql.SQLException

Gets the best Query found so far

Specified by:

getBestQuery in class BestQuery

Returns:

the best Query, or null if no Queries added to this object

Throws:

java.sql.SQLException - if an error occurs in the underlying database

getBestQueryString

public java.lang.String getBestQueryString()
                                    throws java.sql.SQLException

Gets the best query String found so far.

Specified by:

getBestQueryString in class BestQuery

Returns:

the best Query, or null if no Queries added to this object

Throws:

java.sql.SQLException - if an error occurs in the underlying database

getBestExplainResult

public ExplainResult getBestExplainResult()
                                   throws java.sql.SQLException

Gets the ExpainResult for the best Query found so far.

Returns:

the best ExplainResult, or null if no Queries added to this object

Throws:

java.sql.SQLException - if an error occurs in the underlying database

getBest

protected BestQueryExplainer.Candidate getBest()
                                        throws java.sql.SQLException

Gets the best Candidate found so far.

Returns:

the best Candidate

Throws:

java.sql.SQLException - if an error occurs in the underlying database

throwBestQueryException

public void throwBestQueryException(java.lang.String message)
                             throws BestQueryException

Throws an exception. This gives the subclasses a chance to intercept it.

Parameters:

message - a message

Throws:

BestQueryException - with the message