[ https://issues.apache.org/jira/browse/CALCITE-5944?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17759235#comment-17759235 ]
Jiajun Xie commented on CALCITE-5944: ------------------------------------- Would anyone please review it? > Add metadata for Sample > ----------------------- > > Key: CALCITE-5944 > URL: https://issues.apache.org/jira/browse/CALCITE-5944 > Project: Calcite > Issue Type: Improvement > Components: core > Reporter: Jiajun Xie > Assignee: Jiajun Xie > Priority: Minor > Labels: pull-request-available > > For the sql > {code:java} > select * from emp tablesample system(20) {code} > `mq.getRowCount(rel)` is null, but we can return `inputRowCount * 0.2`. > > Some metadata need to be implemented. > * RelMdAllPredicates > * RelMdColumnOrigins > * RelMdExpressionLineage > * RelMdMaxRowCount > * RelMdMinRowCount > * RelMdPredicates > * RelMdRowCount > Some metadata have been implemented. > * RelMdTableReferences > * RelMdNodeTypes > Some metadabata not need to be implemented. > * RelMdColumnUniqueness (Handle SingleRel) > * RelMdDistribution (Handle SingleRel) > * RelMdDistinctRowCount(Handle RelNode) > * RelMdExplainVisibility(Only TableScan) > * RelMdLowerBoundCost(Handle RelNode) > * RelMdMemory(Handle RelNode) > * RelMdParallelism(Handle RelNode) > * RelMdPercentageOriginalRows(Handle RelNode) > * RelMdPopulationSize(Handle RelNode) > * RelMdSelectivity(Must have predicate) > * RelMdSize(Handle RelNode) > * RelMdUniqueKeys(Handle SingleRel) -- This message was sent by Atlassian Jira (v8.20.10#820010)