core/sql/refresh/RuTableSyncTask.h

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#ifndef _RU_TABLE_SYNC_TASK_H_
#define _RU_TABLE_SYNC_TASK_H_

/* -*-C++-*-
******************************************************************************
*
* File:         RuTableSyncTask.h
* Description:  Definition of class CRUTableSyncTask.
*
* Created:      12/06/2000
* Language:     C++
*
*
******************************************************************************
*/

#include "refresh.h"

#include "RuLogProcessingTask.h"

class CRURefreshTask;

//--------------------------------------------------------------------------//
//	CRUTableSyncTask
//	
//  The task will be responsible for the following actions
//	1.	Increment the epoch of a table that needs it (when ever the log may 
//      be consumed in this refresh invocation),this stage may be executed in 
//		the remote process
//	2.  Lock the table in case a long lock is needed (long lock is a lock 
//      that remains until the last mv that required that lock has been 
//		refreshed)
//	3.  Save the syncronization timestamp in the table object for further 
//		use	
//
//	The epoch increment separates the records that have been logged
//	*before* and *after* the refresh has started (i.e., defines the
//	delta's upper boundary. The read-protected open of a table is a 
//	non-transactional shared lock which "freezes" the table for the 
//	time of refresh. This is a requirement for ON REQUEST MVs that 
//	use both the table and the log for refresh, and for RECOMPUTED mv's that 
//  use an mv object join with other objects
//
//
//--------------------------------------------------------------------------//

class REFRESH_LIB_CLASS CRUTableSyncTask : public CRULogProcessingTask {

	//---------------------------------------//
	//	Public Memebers
	//---------------------------------------//
public:
	CRUTableSyncTask(Lng32 id, CRUTbl &table);
	virtual ~CRUTableSyncTask();

public:
	//-- Implementation of pure virtuals
	virtual CRUTask::Type GetType() const 
	{ 
		return CRUTask::TABLE_SYNC; 
	}

	//---------------------------------------//
	//	Protected Memebers
	//---------------------------------------//

protected:
	virtual CDSString GetTaskName() const;

	// Create the concrete task executor
	virtual CRUTaskExecutor *CreateExecutorInstance();

	virtual TInt32 GetComputedCost() const
	{
		return 0;
	}

	virtual BOOL IsImmediate() const
	{
		return GetTable().IsNoLockOnRefresh();
	}

	//---------------------------------------//
	//	Private Memebers
	//---------------------------------------//
private:
	//-- Prevent copying
	CRUTableSyncTask(const CRUTableSyncTask &other);
	CRUTableSyncTask& operator= (const CRUTableSyncTask &other);
};

#endif