TupleIterator Class Reference

#include <TableImpl.h>

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Public Member Functions
	TupleIterator (Predicate *p, ScanType t, IndexInfo *i, void *cptr, int pslot)
	~TupleIterator ()
DbRetVal	open ()
void *	next ()
DbRetVal	close ()

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Detailed Description

Definition at line 38 of file TableImpl.h.

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Constructor & Destructor Documentation

TupleIterator::TupleIterator	(	Predicate *	p,
		ScanType	t,
		IndexInfo *	i,
		void *	cptr,
		int	pslot
	)			[inline]

Definition at line 51 of file TableImpl.h.

    { bIter = NULL; pred_ = p ; scanType_ = t; info = i; chunkPtr_ = cptr; procSlot =pslot;}

TupleIterator::~TupleIterator

(

)

[inline]

Definition at line 54 of file TableImpl.h.

        { 
        if (bIter) delete bIter; 
        bIter = NULL; 
    }

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Member Function Documentation

DbRetVal TupleIterator::close

(

)

Definition at line 123 of file TupleIterator.cxx.

References fullTableScan, hashIndexScan, OK, and unknownScan.

Referenced by TableImpl::close().

{
    if (scanType_ == fullTableScan)
    {
        delete cIter;
        cIter = NULL;
    } else if (scanType_ == hashIndexScan)
    {
            delete bIter;
            bIter = NULL;
        }
    scanType_ = unknownScan;
    return OK;
}

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void * TupleIterator::next

(

)

Definition at line 61 of file TupleIterator.cxx.

References DM_HashIndex, DM_Table, PredicateImpl::evaluate(), fullTableScan, hashIndexScan, BucketIter::next(), ChunkIterator::nextElement(), OK, printDebug, HashIndexNode::ptrToTuple_, and PredicateImpl::setTuple().

Referenced by TableImpl::fetchNoBind().

{
    PredicateImpl *predImpl = (PredicateImpl*) pred_;
    void *tuple = NULL;
    DbRetVal rv = OK;
    if (fullTableScan == scanType_)
    {

        if (NULL == pred_ )
        {
            //no predicates
            return cIter->nextElement();
        }
        else
        {
            //evaluate till it succeeds
            bool result = false;
            while (!result)
            {
                tuple = cIter->nextElement();
                if(NULL == tuple) return NULL;
                predImpl->setTuple(tuple);
                printDebug(DM_Table, "Evaluating the predicate from fullTableScan");
                rv = predImpl->evaluate(result);
                if (rv != OK) return NULL;
            }
        }
    }else if (hashIndexScan == scanType_)
    {
        if (NULL == bIter)
        {
            //if there are no nodes in bucket bIter will be null
            return NULL;
        }
        //evaluate till it succeeds
        bool result = false;
        while (!result)
        {
            HashIndexNode *node = bIter->next();
            if (node == NULL) return NULL;
            printDebug(DM_HashIndex, "next: returned HashIndexNode: %x", node);
            tuple = node->ptrToTuple_;
            if(NULL == tuple) {
                printDebug(DM_HashIndex, "next::tuple is null");
                return NULL;
           }

            //if (!predImpl->isSingleTerm()) {
               printDebug(DM_HashIndex, "next: predicate has more than single term");
               predImpl->setTuple(tuple);
               printDebug(DM_Table, "Evaluating the predicate from hashIndexScan: has more than one term");
               rv = predImpl->evaluate(result);
               if (rv != OK) return NULL;
            //} 
            //else 
            //    return tuple;
        }

    }
    return tuple;
}

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DbRetVal TupleIterator::open

(

)

Definition at line 23 of file TupleIterator.cxx.

References Bucket::bucketList_, SingleFieldHashIndexInfo::buckets, HashIndex::computeHashBucket(), DM_HashIndex, ErrLockTimeOut, SingleFieldHashIndexInfo::fldName, fullTableScan, Mutex::getLock(), hashIndexScan, Bucket::mutex_, SingleFieldHashIndexInfo::noOfBuckets, OK, printDebug, printError, Mutex::releaseLock(), SingleFieldHashIndexInfo::type, and PredicateImpl::valPtrForIndexField().

Referenced by TableImpl::execute().

{

    if (fullTableScan == scanType_)
    {
        cIter = new ChunkIterator();
        *cIter = ((Chunk*)chunkPtr_)->getIterator();
    }else if (hashIndexScan == scanType_)
    {
        SingleFieldHashIndexInfo *hIdxInfo = (SingleFieldHashIndexInfo*)info;
        PredicateImpl *predImpl = (PredicateImpl*) pred_;
        bool isPtr = false;
        void *keyPtr = (void*)predImpl->valPtrForIndexField(hIdxInfo->fldName);

        int bucketNo = HashIndex::computeHashBucket(hIdxInfo->type,
                        keyPtr, hIdxInfo->noOfBuckets);
        Bucket *bucket =  &(hIdxInfo->buckets[bucketNo]);
        int ret = bucket->mutex_.getLock(procSlot);
        if (ret != 0)
        {
            printError(ErrLockTimeOut,"Unable to acquire bucket Mutex for bucket %d",bucketNo);
            return ErrLockTimeOut;
        }
        HashIndexNode *head = (HashIndexNode*) bucket->bucketList_;
        if (!head)
        {
            bucket->mutex_.releaseLock(procSlot);
            bIter = NULL ;
            return OK;
        }
        printDebug(DM_HashIndex, "open:head for bucket %x is :%x", bucket, head);
        bIter  = new BucketIter(head);
        bucket->mutex_.releaseLock(procSlot);
    }
    return OK;
}

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The documentation for this class was generated from the following files:

• include/TableImpl.h
• src/server/TupleIterator.cxx

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