net.sf.farrago.db
Class FarragoDbStmtContextBase

java.lang.Object
  net.sf.farrago.db.FarragoDbStmtContextBase

All Implemented Interfaces:

FarragoSessionStmtContext, FarragoAllocation, ClosableAllocation

Direct Known Subclasses:

FarragoDbStmtContext

public abstract class FarragoDbStmtContextBase
extends Object
implements FarragoSessionStmtContext

FarragoDbStmtContextBase provides a partial implementation of FarragoSessionStmtContext in terms of FarragoDbSession.

The basic funtionality provided here may be extended to implement statements in a way specific to extension projects.

See individual methods for assistance in determining when they may be called.

Most non-trivial public methods on this class must be synchronized on the parent session, since closeAllocation may be called from a thread shutting down the database. The exception is cancel, which must NOT be synchronized, since it needs to return immediately. (We synchronize on the parent session to avoid deadlocks from session/stmt vs. stmt/session lock order; see http://issues.eigenbase.org/browse/LDB-150 for an example.)

Author:

Stephan Zuercher

Field Summary

protected CancelFlag	cancelFlag
protected List<FarragoSessionStmtContext>	childrenStmtContexts The children statement contexts associated with a root statement context.
protected boolean	daemon
private FarragoDdlLockManager	ddlLockManager
protected FarragoSessionStmtParamDef[]	dynamicParamDefs Definitions of dynamic parameters.
protected Object[]	dynamicParamValues Current dynamic parameter bindings.
protected boolean[]	dynamicParamValuesSet Indicates if dynamic parameter is set Used to validate that all dynamic parameters have been set
private FarragoSessionExecutingStmtInfo	info
protected FarragoSessionStmtParamDefFactory	paramDefFactory
protected FarragoSessionStmtContext	rootStmtContext
protected boolean	saveFirstCsn Indicates whether the csn associated with the first txn initiated from a root context or one of its children contexts needs to be saved.
protected FarragoDbSession	session
protected Long	snapshotCsn If non-null, the commit sequence number to be used for all transactions associated with a root context as well as children contexts associated with that root context.
protected String	sql
private long	stmtCurrentTime
protected static Logger	tracer

Constructor Summary

protected	FarragoDbStmtContextBase(FarragoDbSession session, FarragoSessionStmtParamDefFactory paramDefFactory, FarragoDdlLockManager ddlLockManager) Creates a new FarragoDbStmtContextBase object.
protected	FarragoDbStmtContextBase(FarragoDbSession session, FarragoSessionStmtParamDefFactory paramDefFactory, FarragoDdlLockManager ddlLockManager, FarragoSessionStmtContext rootStmtContext) Creates a new FarragoDbStmtContextBase object.

Method Summary

protected void	accessTable(List<String> table, TableAccessMap.Mode mode) Acquires locks (or whatever transaction manager wants) on a single table.
protected void	accessTables(FarragoSessionExecutableStmt executableStmt) Acquires locks (or whatever transaction manager wants) on all tables accessed by this statement.
void	addChildStmtContext(FarragoSessionStmtContext childStmtContext) Adds a child statement context to the list of children context for a statement.
protected void	checkDynamicParamsSet() Checks that all dynamic parameters have been set.
protected void	clearExecutingStmtInfo() Clears session's FarragoSessionExecutingStmtInfo.
void	clearParameters() Clears any settings for all dynamic parameters.
void	closeAllocation() Closes this object.
void	daemonize() Turns this context into a daemon so that it will be deallocated as soon as its current result set is closed.
CancelFlag	getCancelFlag() Gets the cancellation flag for this context.
FarragoSessionExecutingStmtInfo	getExecutingStmtInfo() Returns an object which contains information about this executing statement.
FarragoSession	getSession()
private FarragoDbSessionInfo	getSessionInfo()
String	getSql()
long	getStmtCurrentTime()
protected void	initDynamicParams(RelDataType dynamicParamRowType) Initializes the dynamicParamDefs and dynamicParamValues arrays based on the dynamic param row type,
protected void	initExecutingStmtInfo(FarragoSessionExecutableStmt executableStmt) Initializes the session's FarragoSessionExecutingStmtInfo.
protected void	lockObjectInUse(String mofId) Marks a single object, represented by its mofId, as in-use.
protected void	lockObjectsInUse(FarragoSessionExecutableStmt newExecutableStmt) See FarragoDbSession.
private void	lockTables(TableAccessMap accessMap) Calls the transaction manager to access a set of tables.
boolean	needToSaveFirstTxnCsn()
void	saveFirstTxnCsn(long csn) Saves the commit sequence number associated with the first transaction initiated by a stmt associated with a root context.
void	setDynamicParam(int parameterIndex, Object x) Sets an input parameter.
void	setDynamicParam(int parameterIndex, Object x, Calendar cal) Sets an input parameter.
void	setSaveFirstTxnCsn() Indicates that the context needs to retrieve and save the commit sequence number for the very first transaction initiated by a stmt context associated with a root context.
protected void	startAutocommitTxn(boolean readOnly) Starts an auto commit transaction.
protected void	traceExecute() Traces execution.
void	unprepare() Releases any resources (including result sets) associated with this statement context.

Methods inherited from class java.lang.Object

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

Methods inherited from interface net.sf.farrago.session.FarragoSessionStmtContext

cancel, closeResultSet, execute, getPreparedParamType, getPreparedRowType, getQueryTimeout, getResultSet, getUpdateCount, getWarningQueue, isPrepared, isPreparedDml, kill, prepare, prepare, setQueryTimeout

Field Detail

tracer

protected static final Logger tracer

session

protected final FarragoDbSession session

paramDefFactory

protected final FarragoSessionStmtParamDefFactory paramDefFactory

dynamicParamDefs

protected FarragoSessionStmtParamDef[] dynamicParamDefs

Definitions of dynamic parameters.

dynamicParamValues

protected Object[] dynamicParamValues

Current dynamic parameter bindings.

dynamicParamValuesSet

protected boolean[] dynamicParamValuesSet

Indicates if dynamic parameter is set Used to validate that all dynamic parameters have been set

daemon

protected boolean daemon

sql

protected String sql

ddlLockManager

private FarragoDdlLockManager ddlLockManager

info

private FarragoSessionExecutingStmtInfo info

stmtCurrentTime

private final long stmtCurrentTime

rootStmtContext

protected final FarragoSessionStmtContext rootStmtContext

childrenStmtContexts

protected List<FarragoSessionStmtContext> childrenStmtContexts

The children statement contexts associated with a root statement context.

snapshotCsn

protected Long snapshotCsn

If non-null, the commit sequence number to be used for all transactions associated with a root context as well as children contexts associated with that root context. Only used if the personality supports snapshots.

saveFirstCsn

protected boolean saveFirstCsn

Indicates whether the csn associated with the first txn initiated from a root context or one of its children contexts needs to be saved. Only used if the personality supports snapshots.

cancelFlag

protected final CancelFlag cancelFlag

Constructor Detail

FarragoDbStmtContextBase

protected FarragoDbStmtContextBase(FarragoDbSession session,
                                   FarragoSessionStmtParamDefFactory paramDefFactory,
                                   FarragoDdlLockManager ddlLockManager)

Creates a new FarragoDbStmtContextBase object.

Parameters:

session - the session creating this statement

paramDefFactory - dynamic parameter definition factory

ddlLockManager - ddl object lock manager

FarragoDbStmtContextBase

protected FarragoDbStmtContextBase(FarragoDbSession session,
                                   FarragoSessionStmtParamDefFactory paramDefFactory,
                                   FarragoDdlLockManager ddlLockManager,
                                   FarragoSessionStmtContext rootStmtContext)

Creates a new FarragoDbStmtContextBase object.

Parameters:

session - the session creating this statement

paramDefFactory - dynamic parameter definition factory

ddlLockManager - ddl object lock manager

rootStmtContext - the root statement context for an internally prepared statement; for an externally prepared statement, this will be null

Method Detail

closeAllocation

public void closeAllocation()

Description copied from interface: ClosableAllocation

Closes this object.

Specified by:

closeAllocation in interface ClosableAllocation

getSession

public FarragoSession getSession()

Specified by:

getSession in interface FarragoSessionStmtContext

Returns:

the session from which this statement context was created

getExecutingStmtInfo

public FarragoSessionExecutingStmtInfo getExecutingStmtInfo()

Description copied from interface: FarragoSessionStmtContext

Returns an object which contains information about this executing statement.

Specified by:

getExecutingStmtInfo in interface FarragoSessionStmtContext

Returns:

FarragoSessionExecutingStmtInfo

daemonize

public void daemonize()

Description copied from interface: FarragoSessionStmtContext

Turns this context into a daemon so that it will be deallocated as soon as its current result set is closed.

Specified by:

daemonize in interface FarragoSessionStmtContext

unprepare

public void unprepare()

Description copied from interface: FarragoSessionStmtContext

Releases any resources (including result sets) associated with this statement context.

Specified by:

unprepare in interface FarragoSessionStmtContext

setDynamicParam

public void setDynamicParam(int parameterIndex,
                            Object x)

Description copied from interface: FarragoSessionStmtContext

Sets an input parameter.

Specified by:

setDynamicParam in interface FarragoSessionStmtContext

Parameters:

parameterIndex - 0-based index of parameter to set

x - value to set

setDynamicParam

public void setDynamicParam(int parameterIndex,
                            Object x,
                            Calendar cal)

Description copied from interface: FarragoSessionStmtContext

Sets an input parameter.

Specified by:

setDynamicParam in interface FarragoSessionStmtContext

Parameters:

parameterIndex - 0-based index of parameter to set

x - value to set

clearParameters

public void clearParameters()

Description copied from interface: FarragoSessionStmtContext

Clears any settings for all dynamic parameters.

Specified by:

clearParameters in interface FarragoSessionStmtContext

getSql

public String getSql()

Specified by:

getSql in interface FarragoSessionStmtContext

getStmtCurrentTime

public long getStmtCurrentTime()

Specified by:

getStmtCurrentTime in interface FarragoSessionStmtContext

Returns:

the current time for this statement

setSaveFirstTxnCsn

public void setSaveFirstTxnCsn()

Description copied from interface: FarragoSessionStmtContext

Indicates that the context needs to retrieve and save the commit sequence number for the very first transaction initiated by a stmt context associated with a root context. Can only be called on the root context.

Specified by:

setSaveFirstTxnCsn in interface FarragoSessionStmtContext

needToSaveFirstTxnCsn

public boolean needToSaveFirstTxnCsn()

Specified by:

needToSaveFirstTxnCsn in interface FarragoSessionStmtContext

Returns:

whether the context needs to retrieve and save the commit sequence number for the very first transaction initiated by a stmt context associated with a root context; can only be called on the root context

saveFirstTxnCsn

public void saveFirstTxnCsn(long csn)

Description copied from interface: FarragoSessionStmtContext

Saves the commit sequence number associated with the first transaction initiated by a stmt associated with a root context. Can only be called on the root context.

Specified by:

saveFirstTxnCsn in interface FarragoSessionStmtContext

Parameters:

csn - the commit sequence number

addChildStmtContext

public void addChildStmtContext(FarragoSessionStmtContext childStmtContext)

Description copied from interface: FarragoSessionStmtContext

Adds a child statement context to the list of children context for a statement. Can only be called on the root context.

Specified by:

addChildStmtContext in interface FarragoSessionStmtContext

startAutocommitTxn

protected void startAutocommitTxn(boolean readOnly)

Starts an auto commit transaction.

Call near the beginning of FarragoSessionStmtContext.execute().

Parameters:

readOnly - true if statement is read only (e.g. not DML)

initDynamicParams

protected void initDynamicParams(RelDataType dynamicParamRowType)

Initializes the dynamicParamDefs and dynamicParamValues arrays based on the dynamic param row type,

Call after statement preparation, when the dynamic param row type is known, but before FarragoSessionStmtContext.setDynamicParam(int, Object) or FarragoSessionStmtContext.clearParameters().

Parameters:

dynamicParamRowType - dynamic param row type (e.g., FarragoSessionExecutableStmt.getDynamicParamRowType()

checkDynamicParamsSet

protected void checkDynamicParamsSet()

Checks that all dynamic parameters have been set.

accessTables

protected void accessTables(FarragoSessionExecutableStmt executableStmt)

Acquires locks (or whatever transaction manager wants) on all tables accessed by this statement.

Call during FarragoSessionStmtContext.execute() to lock tables used by your FarragoSessionExecutableStmt.

Parameters:

executableStmt - executable statement

accessTable

protected void accessTable(List<String> table,
                           TableAccessMap.Mode mode)

Acquires locks (or whatever transaction manager wants) on a single table.

Parameters:

table - fully qualified table name, represented as a list

mode - access mode for the table

lockTables

private void lockTables(TableAccessMap accessMap)

Calls the transaction manager to access a set of tables.

Parameters:

accessMap - map containing the tables being accessed and their access modes

lockObjectsInUse

protected void lockObjectsInUse(FarragoSessionExecutableStmt newExecutableStmt)

See FarragoDbSession.

Call from FarragoSessionStmtContext.prepare(RelNode, SqlKind, boolean, FarragoSessionPreparingStmt) after preparation is complete.

Parameters:

newExecutableStmt -

lockObjectInUse

protected void lockObjectInUse(String mofId)

Marks a single object, represented by its mofId, as in-use.

Parameters:

mofId - mofId of the object being marked as in-use

initExecutingStmtInfo

protected void initExecutingStmtInfo(FarragoSessionExecutableStmt executableStmt)

Initializes the session's FarragoSessionExecutingStmtInfo.

Call before FarragoSessionExecutableStmt.execute( FarragoSessionRuntimeContext).

Parameters:

executableStmt - executable statement

clearExecutingStmtInfo

protected void clearExecutingStmtInfo()

Clears session's FarragoSessionExecutingStmtInfo.

Call on FarragoSessionStmtContext.cancel(), FarragoSessionStmtContext.closeResultSet(), or whenever the statement is known to have stopped executing.

getCancelFlag

public CancelFlag getCancelFlag()

Description copied from interface: FarragoSessionStmtContext

Gets the cancellation flag for this context. This is part of the implementation of cancel-checking; callers who actually want to request cancellation should use the FarragoSessionStmtContext.cancel() method instead.

Specified by:

getCancelFlag in interface FarragoSessionStmtContext

Returns:

the cancellation flag for this context

traceExecute

protected void traceExecute()

Traces execution.

Optionally, call from FarragoSessionStmtContext.execute().

getSessionInfo

private FarragoDbSessionInfo getSessionInfo()