private void handleFilter(FilterTuple filterTuple, FilterExpr expr) {
/*
* CompareEQ expressions are inserted as bindings if possible
*
* if the filtertuple contains all vars of the filterexpr, we
* can evaluate the filter expr safely on the filterTuple
*
* if there is no intersection of variables, the filter is
* irrelevant for this expr
*
* if there is some intersection, we cannot remove the filter
* and have to keep it in the query plan for postfiltering
*/
int intersected = 0;
for (String filterVar : expr.getVars()) {
if (filterTuple.getFreeVars().contains(filterVar)) intersected++;
}
// filter expression is irrelevant
if (intersected == 0) return;
// push eq comparison into stmt as bindings
if (expr.isCompareEq()) {
if (handleCompare(filterTuple, (Compare) expr.getExpression())) return;
}
// filter contains all variables => push filter
if (intersected == expr.getVars().size()) filterTuple.addFilterExpr(expr);
// filter is still needed for post filtering
else {
canRemove = false;
}
}
