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Posted to dev@calcite.apache.org by "Luis Fernando Kauer (JIRA)" <ji...@apache.org> on 2017/07/27 12:34:01 UTC
[jira] [Created] (CALCITE-1906) JdbcSortRule has a bug and it is
chosen
Luis Fernando Kauer created CALCITE-1906:
--------------------------------------------
Summary: JdbcSortRule has a bug and it is chosen
Key: CALCITE-1906
URL: https://issues.apache.org/jira/browse/CALCITE-1906
Project: Calcite
Issue Type: Bug
Components: jdbc-adapter
Reporter: Luis Fernando Kauer
Assignee: Julian Hyde
JdbcSortRule tries to push sort and limit operations to the database.
Currently offset and limit operations are explicitly not pushed to the database (prevented by the rule) but even sort operations end up not being pushed.
Checking how other adapters deal with this, like Mongo and Cassandra adapters, I realized that the convert function from JdbcSortRule is different from the others.
Jdbc-adapter:
{{
if (sort.offset != null || sort.fetch != null) {
// Cannot implement "OFFSET n FETCH n" currently.
return null;
}
final RelTraitSet traitSet = sort.getTraitSet().replace(out);
return new JdbcSort(rel.getCluster(), traitSet,
convert(sort.getInput(), traitSet), sort.getCollation());
}}
mongodb-adapter:
{{
final RelTraitSet traitSet =
sort.getTraitSet().replace(out)
.replace(sort.getCollation());
return new MongoSort(rel.getCluster(), traitSet,
convert(sort.getInput(), traitSet.replace(RelCollations.EMPTY)),
sort.getCollation(), sort.offset, sort.fetch);
}}
By fixing JdbcSortRule so that it is just like those others and by removing the code that prevented the rule to match when limit or offset are used seems to solve the problem and JdbcSortRule now is being applied and both sort and limit are being pushed to the database.
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