Github user zellerh commented on a diff in the pull request:
https://github.com/apache/incubator-trafodion/pull/255#discussion_r49411689
--- Diff: core/sql/generator/GenPreCode.cpp ---
@@ -11274,6 +11274,485 @@ short
HbaseAccess::extractHbaseFilterPreds(Generator * generator,
return 0;
}
+////////////////////////////////////////////////////////////////////////////
+// To push down, the predicate must have the following form:
+// xp:= <column> <op> <value-expr>
+// xp:= <column> is not null (no support for hbase lookup)
+// xp:= <column> is null (no support for hbase lookup)
+// (xp:=<column> like <value-expr> not yet implemented)
+// xp:=<xp> OR <xp> (not evaluated in isHbaseFilterPredV2, but by
extractHbaseFilterPredV2)
+// xp:=<xp> AND <xp>(not evaluated in isHbaseFilterPredV2, but by
extractHbaseFilterPredV2)
+//
+// and all of the following conditions must be met:
+//
+// <column>: a base table or index column which can be
serialized and belong to the table being scanned.
+// serialized: either the column doesn't need
encoding, like
+// an unsigned integer, or the
column
+// was declared with the
SERIALIZED option.
+// it also must not be an added
column with default non null.
+// <op>: eq, ne, gt, ge, lt, le
+// <value-expr>: an expression that only contains const or param
values, and
+// <value-expr>'s datatype is not a superset of
<column>'s datatype.
+//
+/////////////////////////////////////////////////////////////////////////////
+NABoolean HbaseAccess::isHbaseFilterPredV2(Generator * generator, ItemExpr
* ie,
+ ValueId &colVID, ValueId &valueVID,
+ NAString &op)
+{
+ NABoolean foundBinary = FALSE;
+ NABoolean foundUnary = FALSE;
+ NABoolean hbaseLookupPred = FALSE;
+ NABoolean flipOp = FALSE; // set to TRUE when column is child(1)
+
+ if (ie &&
+ ((ie->getOperatorType() >= ITM_EQUAL) &&
+ (ie->getOperatorType() <= ITM_GREATER_EQ))) //binary operator case
+ {//begin expression
+ ItemExpr * child0 = ie->child(0)->castToItemExpr();
+ ItemExpr * child1 = ie->child(1)->castToItemExpr();
+
+ if ((ie->child(0)->getOperatorType() == ITM_BASECOLUMN) &&
+ (NOT hasColReference(ie->child(1))))
--- End diff --
Sorry, I'm not deep enough in the code yet, so I'll just ask: Is
hasColReference() a good enough test for HBase filters? In other words, if we
have functions like substring(), cos() in the expression, or parameters, are
those ok to be evaluated before we make the comparison value for the filter?
Probably yes, just checking.
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