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Posted to issues@calcite.apache.org by "Vladimir Sitnikov (Jira)" <ji...@apache.org> on 2020/10/11 13:29:00 UTC
[jira] [Commented] (CALCITE-4327) RelBuilder#scan(...) should work
when used in RelRule#onMatch as call.builder()
[ https://issues.apache.org/jira/browse/CALCITE-4327?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17211917#comment-17211917 ]
Vladimir Sitnikov commented on CALCITE-4327:
--------------------------------------------
[~julianhyde], what do you think of moving {{RelOptSchema relOptSchema}} from a field to {{scan}} argument?
My current code (~calcite 1.19):
{code:java}
@Override
public void onMatch(RelOptRuleCall call) {
InstanceByClassTableScan scan = call.rel(0);
RelOptTable table = scan.getTable();
RelOptSchema schema = table.getRelOptSchema();
List<String> indexName = new ArrayList<String>(table.getQualifiedName());
indexName.set(indexName.size() - 1, "$ids$:" + indexName.get(indexName.size() - 1));
LogicalTableScan ids = LogicalTableScan.create(scan.getCluster(), schema.getTableForMember(indexName));
...
{code}
I tried {{call.builder().scan(indexName)}} instead of {{LogicalTableScan...}}, however it fails with NPE as in description.
It looks like the new way to create TableScan is even worse than before:
{code:java}
public void onMatch(RelOptRuleCall call) {
InstanceByClassTableScan scan = call.rel(0);
RelOptTable table = scan.getTable();
RelOptSchema schema = table.getRelOptSchema();
List<String> indexName = new ArrayList<String>(table.getQualifiedName());
indexName.set(indexName.size() - 1, "$ids$:" + indexName.get(indexName.size() - 1));
RelBuilder relBuilder = call.builder();
relBuilder.push(
relBuilder.getScanFactory().createScan(
ViewExpanders.simpleContext(relBuilder.getCluster()),
schema.getTableForMember(indexName)));
{code}
Then, PigRelBuilder has the following methods which suggest the need is indeed there:
{code:java}
public RelBuilder scan(RelOptTable userSchema, String... tableNames) {
...
}
private RelBuilder scan(RelOptTable tableSchema) {
final RelNode scan = getScanFactory().createScan(
ViewExpanders.simpleContext(cluster), tableSchema);
push(scan);
return this;
}
{code}
> RelBuilder#scan(...) should work when used in RelRule#onMatch as call.builder()
> -------------------------------------------------------------------------------
>
> Key: CALCITE-4327
> URL: https://issues.apache.org/jira/browse/CALCITE-4327
> Project: Calcite
> Issue Type: Sub-task
> Components: core
> Affects Versions: 1.26.0
> Reporter: Vladimir Sitnikov
> Priority: Major
>
> It turns out {{RelBuilder#relOptSchema}} is often null.
> For instance,
> {code:java}
> public abstract class RelOptRuleCall {
> public RelBuilder builder() {
> return rule.relBuilderFactory.create(rel(0).getCluster(), /* schema= */ null);
> }
> {code}
> It leads to NPE in user code.
> I suggest either populate {{relOptSchema}} with root schema by default or remove the field to avoid confusion for those who would try {{scan(...)}} method.
> It might make sense to add RelOptSchema parameter to {{scan(Iterable<String>)}} method as well.
> Sample use case:
> {code:java}
> @Override
> public void onMatch(RelOptRuleCall call) {
> List<String> indexName = ...;
> RelBuilder relBuilder = call.builder()
> .scan(indexName);
> {code}
> {noformat}
> Caused by: java.lang.NullPointerException
> at org.apache.calcite.tools.RelBuilder.scan(RelBuilder.java:1094)
> at com.github.vlsi.mat.calcite.schema.objects.InstanceAccessByClassIdRule.onMatch(InstanceAccessByClassIdRule.java:44)
> at org.apache.calcite.plan.volcano.VolcanoRuleCall.onMatch(VolcanoRuleCall.java:229)
> ... 75 more
> {noformat}
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