short ProbeCache::codeGen(Generator *generator)
{
ExpGenerator * exp_gen = generator->getExpGenerator();
Space * space = generator->getSpace();
MapTable * last_map_table = generator->getLastMapTable();
ex_cri_desc * given_desc
= generator->getCriDesc(Generator::DOWN);
ex_cri_desc * returned_desc
= new(space) ex_cri_desc(given_desc->noTuples() + 1, space);
// cri descriptor for work atp has 5 entries:
// entry #0 for const
// entry #1 for temp
// entry #2 for hash value of probe input data in Probe Cache Manager
// entry #3 for encoded probe input data in Probe Cache Manager
// enrry #4 for inner table row data in this operator's cache buffer
Int32 work_atp = 1;
ex_cri_desc * work_cri_desc = new(space) ex_cri_desc(5, space);
unsigned short hashValIdx = 2;
unsigned short encodedProbeDataIdx = 3;
unsigned short innerRowDataIdx = 4;
// generate code for child tree, and get its tdb and explain tuple.
child(0)->codeGen(generator);
ComTdb * child_tdb = (ComTdb *)(generator->getGenObj());
ExplainTuple *childExplainTuple = generator->getExplainTuple();
//////////////////////////////////////////////////////
// Generate up to 4 runtime expressions.
//////////////////////////////////////////////////////
// Will use child's char. inputs (+ execution count) for the next
// two runtime expressions.
ValueIdList inputsToUse = child(0).getGroupAttr()->getCharacteristicInputs();
inputsToUse.insert(generator->getOrAddStatementExecutionCount());
// Expression #1 gets the hash value of the probe input data
ValueIdList hvAsList;
// Executor has hard-coded assumption that the result is long,
// so add a Cast node to convert result to a long.
ItemExpr *probeHashAsIe = new (generator->wHeap())
HashDistPartHash(inputsToUse.rebuildExprTree(ITM_ITEM_LIST));
probeHashAsIe->bindNode(generator->getBindWA());
NumericType &nTyp = (NumericType &)probeHashAsIe->getValueId().getType();
GenAssert(nTyp.isSigned() == FALSE,
"Unexpected signed HashDistPartHash.");
GenAssert(probeHashAsIe->getValueId().getType().supportsSQLnullLogical()
== FALSE, "Unexpected nullable HashDistPartHash.");
ItemExpr *hvAsIe = new (generator->wHeap()) Cast(
probeHashAsIe,
new (generator->wHeap())
SQLInt(FALSE, // false == unsigned.
FALSE // false == not nullable.
));
hvAsIe->bindNode(generator->getBindWA());
hvAsList.insert(hvAsIe->getValueId());
ex_expr *hvExpr = NULL;
ULng32 hvLength;
exp_gen->generateContiguousMoveExpr(
hvAsList,
0, // don't add convert node
work_atp,
hashValIdx,
ExpTupleDesc::SQLARK_EXPLODED_FORMAT,
hvLength,
&hvExpr);
GenAssert(hvLength == sizeof(Lng32),
"Unexpected length of result of hash function.");
// Expression #2 encodes the probe input data for storage in
// the ProbeCacheManager.
ValueIdList encodeInputAsList;
CollIndex inputListIndex;
for (inputListIndex = 0;
inputListIndex < inputsToUse.entries();
inputListIndex++) {
ItemExpr *inputIe =
(inputsToUse[inputListIndex].getValueDesc())->getItemExpr();
if (inputIe->getValueId().getType().getVarLenHdrSize() > 0)
{
// This logic copied from Sort::codeGen().
// Explode varchars by moving them to a fixed field
// whose length is equal to the max length of varchar.
// 5/8/98: add support for VARNCHAR
const CharType& char_type =
(CharType&)(inputIe->getValueId().getType());
if (!CollationInfo::isSystemCollation(char_type.getCollation()))
{
inputIe = new(generator->wHeap())
Cast (inputIe,
(new(generator->wHeap())
SQLChar(
CharLenInfo(char_type.getStrCharLimit(), char_type.getDataStorageSize()),
char_type.supportsSQLnull(),
FALSE, FALSE, FALSE,
char_type.getCharSet(),
char_type.getCollation(),
char_type.getCoercibility()
)
)
);
}
}
CompEncode * enode = new(generator->wHeap())
CompEncode(inputIe, FALSE /* ascend/descend doesn't matter*/);
enode->bindNode(generator->getBindWA());
encodeInputAsList.insert(enode->getValueId());
}
ex_expr *encodeInputExpr = NULL;
ULng32 encodedInputLength;
exp_gen->generateContiguousMoveExpr(encodeInputAsList,
0, //don't add conv nodes
work_atp, encodedProbeDataIdx,
ExpTupleDesc::SQLARK_EXPLODED_FORMAT,
encodedInputLength, &encodeInputExpr);
// Expression #3 moves the inner table data into a buffer pool.
// This is also the tuple returned to ProbeCache's parent.
ex_expr * innerRecExpr = NULL;
ValueIdList innerTableAsList = getGroupAttr()->getCharacteristicOutputs();
//////////////////////////////////////////////////////
// Describe the returned row and add the returned
// values to the map table.
//////////////////////////////////////////////////////
// determine internal format
NABoolean useCif = FALSE;
ExpTupleDesc::TupleDataFormat tupleFormat = generator->getInternalFormat();
//tupleFormat = determineInternalFormat( innerTableAsList, this, useCif,generator);
ULng32 innerRecLength = 0;
ExpTupleDesc * innerRecTupleDesc = 0;
MapTable * returnedMapTable = NULL;
exp_gen->generateContiguousMoveExpr(innerTableAsList,
-1, // do add conv nodes
work_atp, innerRowDataIdx,
tupleFormat,
innerRecLength, &innerRecExpr,
&innerRecTupleDesc, ExpTupleDesc::SHORT_FORMAT,
&returnedMapTable);
returned_desc->setTupleDescriptor(returned_desc->noTuples() - 1,
innerRecTupleDesc);
// remove all appended map tables and return the returnedMapTable
generator->removeAll(last_map_table);
generator->appendAtEnd(returnedMapTable);
// This returnedMapTable will contain the value ids that are being returned
// (the inner table probed).
// Massage the atp and atp_index of the innerTableAsList.
for (CollIndex i = 0; i < innerTableAsList.entries(); i++)
{
ValueId innerValId = innerTableAsList[i];
Attributes *attrib =
generator->getMapInfo(innerValId)->getAttr();
// All reference to the returned values from this point on
// will be at atp = 0, atp_index = last entry in returned desc.
attrib->setAtp(0);
attrib->setAtpIndex(returned_desc->noTuples() - 1);
}
// Expression #4 is a selection predicate, to be applied
// before returning rows to the parent
ex_expr * selectPred = NULL;
if (!selectionPred().isEmpty())
{
ItemExpr * selPredTree =
selectionPred().rebuildExprTree(ITM_AND,TRUE,TRUE);
exp_gen->generateExpr(selPredTree->getValueId(),
ex_expr::exp_SCAN_PRED,
&selectPred);
}
//////////////////////////////////////////////////////
// Prepare params for ComTdbProbeCache.
//////////////////////////////////////////////////////
queue_index pDownSize = (queue_index)getDefault(GEN_PROBE_CACHE_SIZE_DOWN);
queue_index pUpSize = (queue_index)getDefault(GEN_PROBE_CACHE_SIZE_UP);
// Make sure that the ProbeCache queues can support the childs queues.
if(pDownSize < child_tdb->getInitialQueueSizeDown()) {
pDownSize = child_tdb->getInitialQueueSizeDown();
pDownSize = MINOF(pDownSize, 32768);
}
if(pUpSize < child_tdb->getInitialQueueSizeUp()) {
pUpSize = child_tdb->getInitialQueueSizeUp();
pUpSize = MINOF(pUpSize, 32768);
}
ULng32 pcNumEntries = numCachedProbes_;
// Number of entries in the probe cache cannot be less than
// max parent down queue size. Before testing and adjusting the
// max queue size, it is necessary to make sure it is a power of
// two, rounding up if necessary. This is to match the logic in
// ex_queue::resize.
queue_index pdq2 = 1;
queue_index bits = pDownSize;
while (bits && pdq2 < pDownSize) {
bits = bits >> 1;
pdq2 = pdq2 << 1;
}
if (pcNumEntries < pdq2)
pcNumEntries = pdq2;
numInnerTuples_ = getDefault(GEN_PROBE_CACHE_NUM_INNER);
if (innerRecExpr == NULL)
{
// For semi-join and anti-semi-join, executor need not allocate
// a buffer. Set the tdb's buffer size to 0 to be consistent.
numInnerTuples_ = 0;
}
else if (numInnerTuples_ == 0)
{
// Handle special value, 0, which tells code gen to
// decided on buffer size: i.e., large enough to accomodate
// all parent up queue entries and all probe cache entries
// having a different inner table row.
// As we did for the down queue, make sure the up queue size
// specified is a power of two.
queue_index puq2 = 1;
queue_index bits = pUpSize;
while (bits && puq2 < pUpSize) {
bits = bits >> 1;
puq2 = puq2 << 1;
}
numInnerTuples_ = puq2 + pcNumEntries;
}
