> On Oct. 4, 2017, 9:18 p.m., Ashutosh Chauhan wrote: > > ql/src/test/results/clientpositive/llap/vector_ptf_part_simple.q.out > > Line 5616 (original), 5616 (patched) > > <https://reviews.apache.org/r/62776/diff/1/?file=1846209#file1846209line5616> > > > > I would have expected this expression to have been folded in compiler : > > CAST( null AS TIMESTAMP) We have constant folding rules as both calcite as > > well as hive rules. > > Any reason that's not happening here? > > Vineet Garg wrote: > This patch introduces cast for nulls after generating logical plan (while > converting it to AST). That is why there is no constant folding. (In fact > calcite constant folding is folding such expressions does create null with > appropriate type. But during converting logical plan to ast we end up losing > the type and create null with void type, probably because hive doesn't > associate type with nulls) > > Ashutosh Chauhan wrote: > If we have proper type in Calcite, why do we lose type on translation > back? Introducing cast during AST generation feels hackish.
We lose type on translation back because hive doesn't associate any type with null literals. e.g. select case when i=1 then i else null end from t will create GenericUDFWhen(GenericUDFOPEqual(Column[i], Const int 1), Column[i], Const void null) expression for select expr with CBO disabled. As you can notice null literal has void type instead of type corresponding to column[i]. So we need to explicity introduce cast operator in AST to take care of this case. We were already doing this before my patch, it's just the logic wasn't sophisticated enough to do it for expressions embeded inside complex expressions like case, struct etc. - Vineet ----------------------------------------------------------- This is an automatically generated e-mail. To reply, visit: https://reviews.apache.org/r/62776/#review187130 ----------------------------------------------------------- On Oct. 4, 2017, 6:04 p.m., Vineet Garg wrote: > > ----------------------------------------------------------- > This is an automatically generated e-mail. To reply, visit: > https://reviews.apache.org/r/62776/ > ----------------------------------------------------------- > > (Updated Oct. 4, 2017, 6:04 p.m.) > > > Review request for hive, Ashutosh Chauhan and Teddy Choi. > > > Bugs: HIVE-16511 > https://issues.apache.org/jira/browse/HIVE-16511 > > > Repository: hive-git > > > Description > ------- > > This patch fixes an issue with CBO where after generating logical plan null > constants will lose it's cast operator. > > > Diffs > ----- > > itests/src/test/resources/testconfiguration.properties 038487f134 > ql/src/java/org/apache/hadoop/hive/ql/exec/vector/VectorizationContext.java > fcebb6fbce > > ql/src/java/org/apache/hadoop/hive/ql/optimizer/calcite/translator/ASTConverter.java > 165f8c4317 > ql/src/test/results/clientpositive/llap/vector_coalesce.q.out d6865dd0ad > > ql/src/test/results/clientpositive/llap/vector_groupby_grouping_sets_grouping.q.out > ddc1d7be7b > ql/src/test/results/clientpositive/llap/vector_ptf_part_simple.q.out > b63d1e4527 > ql/src/test/results/clientpositive/min_structvalue.q.out PRE-CREATION > ql/src/test/results/clientpositive/perf/spark/query36.q.out c072728803 > ql/src/test/results/clientpositive/perf/spark/query70.q.out 716665bd4f > ql/src/test/results/clientpositive/perf/spark/query86.q.out c5b25e8467 > ql/src/test/results/clientpositive/perf/tez/query36.q.out dee62b58f1 > ql/src/test/results/clientpositive/perf/tez/query70.q.out d700d60345 > ql/src/test/results/clientpositive/perf/tez/query86.q.out 6b59dd254f > ql/src/test/results/clientpositive/vector_coalesce.q.out 445a246cb6 > > > Diff: https://reviews.apache.org/r/62776/diff/1/ > > > Testing > ------- > > > Thanks, > > Vineet Garg > >
