Github user nonstop-qfchen commented on a diff in the pull request:
https://github.com/apache/incubator-trafodion/pull/132#discussion_r42405678
--- Diff: core/sql/optimizer/ItemExpr.cpp ---
@@ -14906,3 +14906,80 @@ NABoolean LOBoper::isCovered
return FALSE;
}
+// Compute the exprssion at compile time. Assume all operands are
constants.
+// Return NULL if the computation fails and CmpCommon::diags() may be
side-affected.
+ConstValue* ItemExpr::compute(CollHeap* heap)
+{
+ ValueIdList exprs;
+ exprs.insert(getValueId());
+
+ const NAType& dataType = getValueId().getType();
+
+ Lng32 decodedValueLen = dataType.getNominalSize() +
dataType.getSQLnullHdrSize();
+
+ char staticDecodeBuf[200];
+ Lng32 staticDecodeBufLen = 200;
+
+ char* decodeBuf = staticDecodeBuf;
+ Lng32 decodeBufLen = staticDecodeBufLen;
+
+ // For character types, multiplying by 8 to deal with conversions between
+ // any two known character sets supported.
+ Lng32 factor = (DFS2REC::isAnyCharacter(dataType.getFSDatatype())) ? 8 :
1;
+
+ if ( staticDecodeBufLen < decodedValueLen * factor) {
+ decodeBufLen = decodedValueLen * factor;
+ decodeBuf = new (STMTHEAP) char[decodeBufLen];
--- End diff --
No. null will not be needed since a binary value will be the result.
On Mon, Oct 19, 2015 at 1:04 PM, DaveBirdsall <[email protected]>
wrote:
> In core/sql/optimizer/ItemExpr.cpp
>
<https://github.com/apache/incubator-trafodion/pull/132#discussion_r42404746>
> :
>
> > +
> > + Lng32 decodedValueLen = dataType.getNominalSize() +
dataType.getSQLnullHdrSize();
> > +
> > + char staticDecodeBuf[200];
> > + Lng32 staticDecodeBufLen = 200;
> > +
> > + char* decodeBuf = staticDecodeBuf;
> > + Lng32 decodeBufLen = staticDecodeBufLen;
> > +
> > + // For character types, multiplying by 8 to deal with conversions
between
> > + // any two known character sets supported.
> > + Lng32 factor = (DFS2REC::isAnyCharacter(dataType.getFSDatatype())) ?
8 : 1;
> > +
> > + if ( staticDecodeBufLen < decodedValueLen * factor) {
> > + decodeBufLen = decodedValueLen * factor;
> > + decodeBuf = new (STMTHEAP) char[decodeBufLen];
>
> We don't care about trailing nulls, right? (Hence, no +1 after
> decodeBufLen)
>
> â
> Reply to this email directly or view it on GitHub
> <https://github.com/apache/incubator-trafodion/pull/132/files#r42404746>.
>
--
Regards, --Qifan
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