[GitHub] [arrow-datafusion] Dandandan commented on a diff in pull request #4276: Reimplement `limit_push_down`

[GitBox <gi...@apache.org>]

Dandandan commented on code in PR #4276:
URL: https://github.com/apache/arrow-datafusion/pull/4276#discussion_r1026602255


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datafusion/optimizer/src/limit_push_down.rs:
##########
@@ -576,8 +424,8 @@ mod test {
 
         // Should push the limit down to table provider
         // When it has a select
-        let expected = "Limit: skip=10, fetch=1000\
-        \n  Projection: test.a\
+        let expected = "Projection: test.a\
+        \n  Limit: skip=10, fetch=1000\
         \n    TableScan: test, fetch=1010";

Review Comment:
   I think we currently don't expect for tablescan to return exactly at most the limit nr of rows AFAIK.
   For this to be possible we need to put some more info into the table scan trait, just like we do with statistics.



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