Github user zellerh commented on a diff in the pull request:
https://github.com/apache/incubator-trafodion/pull/132#discussion_r42520005
--- Diff: core/sql/optimizer/ValueDesc.cpp ---
@@ -6397,3 +6400,111 @@ Lng32 ValueIdList::findPrefixLength(const
ValueIdSet& x) const
return ct;
}
+// -----------------------------------------------------------------------
+// replace any ColReference (of the given column name) in of this value
+// expression with the given expression.
+// used in ValueId::computeEncodedKey() to assign key values into the
+// salt/DivisionByto expression.
+// ----------------------------------------------------------------------
+void ValueId::replaceColReferenceWithExpr(const NAString& colName,
+ const ValueId & vid)
+{
+ ItemExpr* thisItemExpr = getItemExpr();
+ for( Lng32 i = 0; i < thisItemExpr->getArity(); i++ )
+ {
+ ValueId childValueId = thisItemExpr->child(i).getValueId();
+ ItemExpr* childItemExpr = childValueId.getItemExpr();
+
+ if( childItemExpr->getOperatorType() == ITM_REFERENCE)
+ {
+ if( ((ColReference*)childItemExpr)->getColRefNameObj().getColName()
== colName )
+ thisItemExpr->setChild( i, vid.getItemExpr() );
+ }
+ childValueId.replaceColReferenceWithExpr( colName, vid );
+ }
+}
+
+
+char*
+ValueIdList::computeEncodedKey(const TableDesc* tDesc, NABoolean isMaxKey,
+ char*& encodedKeyBuffer, Int32& keyBufLen)
const
+{
+ const NATable* naTable = tDesc->getNATable();
+
+
+ CollIndex count = entries();
+ NAString** inputStrings = new (STMTHEAP) NAStringPtr[count];
+
+ for (Int32 j=0; j<count; j++ )
+ inputStrings[j] = NULL;
+
+ for (Int32 j=0; j<count; j++ ) {
+
+ ValueId vid = (*this)[j];
+ ItemExpr* ie = vid.getItemExpr();
+
+ if ( ie->getOperatorType() != ITM_CONSTANT ) {
+ ConstValue* value = ie->compute(STMTHEAP);
+ if ( !value )
+ return NULL;
+
+ inputStrings[j] = new (STMTHEAP)
NAString(value->getConstStr(FALSE));
--- End diff --
As so often in the compiler we go through complicated paths to get to our
goal, here we already have the binary value, then make it into a string, then
make it back into a binary in encodeKeyValues below. Just an observation, I
don't have a better solution. I wonder whether we should use this compute()
method and ItemExpr::doesExprEvaluateToConstant() in ItemExpr::foldConstants()
to make that method better. Again, just a thought, not a suggestion to change
anything right now, but if we did that, we could just use constantFold() in
this method.
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