[ https://issues.apache.org/jira/browse/DRILL-1328?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15289597#comment-15289597 ]
ASF GitHub Bot commented on DRILL-1328: --------------------------------------- Github user vkorukanti commented on the pull request: https://github.com/apache/drill/pull/425#issuecomment-220124783 Updated patch. Also added a brief design and usage doc to JIRA. Waiting for CALCITE-1241. > Support table statistics > ------------------------ > > Key: DRILL-1328 > URL: https://issues.apache.org/jira/browse/DRILL-1328 > Project: Apache Drill > Issue Type: Improvement > Reporter: Cliff Buchanan > Fix For: Future > > Attachments: 0001-PRE-Set-value-count-in-splitAndTransfer.patch > > > This consists of several subtasks > * implement operators to generate statistics > * add "analyze table" support to parser/planner > * create a metadata provider to allow statistics to be used by optiq in > planning optimization > * implement statistics functions > Right now, the bulk of this functionality is implemented, but it hasn't been > rigorously tested and needs to have some definite answers for some of the > parts "around the edges" (how analyze table figures out where the table > statistics are located, how a table "append" should work in a read only file > system) > Also, here are a few known caveats: > * table statistics are collected by creating a sql query based on the string > path of the table. This should probably be done with a Table reference. > * Case sensitivity for column statistics is probably iffy > * Math for combining two column NDVs into a joint NDV should be checked. > * Schema changes aren't really being considered yet. > * adding getDrillTable is probably unnecessary; it might be better to do > getTable().unwrap(DrillTable.class) -- This message was sent by Atlassian JIRA (v6.3.4#6332)