Github user DaveBirdsall commented on a diff in the pull request:
https://github.com/apache/trafodion/pull/1585#discussion_r191925480
--- Diff: core/sql/optimizer/ItemExpr.cpp ---
@@ -3886,23 +3886,7 @@ ItemExpr * Parameter::copyTopNode(ItemExpr
*derivedNode, CollHeap* outHeap)
ItemExpr * DynamicParam::copyTopNode(ItemExpr *derivedNode, CollHeap*
outHeap)
{
- ItemExpr *result;
-
- if (derivedNode == NULL) {
- result = new (outHeap) DynamicParam(paramName_, indicatorName_,
outHeap);
- ((DynamicParam *) result)->setRowsetSize(rowsetSize_);
- ((DynamicParam *) result)->setRowsetInfo(rowsetInfo_);
- ((DynamicParam *) result)->setParamHeading(heading_);
- ((DynamicParam *) result)->setParamTablename(tablename_);
- // we remember our original dynamic parameter because we
- // must use their valueid at dynamicparam::codegen time
- ((DynamicParam *) result)->setOriginal(this);
- }
-
- else
- result = derivedNode;
-
- return Parameter::copyTopNode(result, outHeap);
+ return this;
--- End diff --
I did a quick experiment. I put a breakpoint at DynamicParam::copyTopNode
in sqlci, then did some prepares using dynamic parameters. I wanted to see if
this method was called to copy a tree into the query cache. I didn't get any
hits. So my tentative conclusion is that this method isn't used for such
copies, or perhaps plans with dynamic parameters are not cacheable (which would
surprise me). In either case though the change looks safe. So I'm OK with it.
---
