The EXPLAIN command allows you to check if Arcadia Engine routed the
user query to either a matching or partially matching analytical view.
On the command line, issue the EXPLAIN command:
[localhost:21050] > explain select distinct(a) from foo;A sample output looks something like this. Note that it indicates that a match has been found, and how the re-write of the query looks.
+--------------------------------------------------------------+
| Explain String |
+--------------------------------------------------------------+
| Estimated Per-Host Requirements: Memory=256.00MB VCores=2 |
| WARNING: The following tables are missing relevant table and |
| /or column statistics. |
| default.av_foo |
| |
| 04:EXCHANGE [PARTITION=UNPARTITIONED] |
| | |
| 03:AGGREGATE [MERGE FINALIZE] |
| | group by: a |
| | |
| 02:EXCHANGE [PARTITION=HASH(a)] |
| | |
| 01:AGGREGATE |
| | group by: a |
| | num_threads: 11 |
| | |
| 00:SCAN HDFS [default.av_foo] |
| partitions=2/2 size=750B |
| |
| REWR : |
| SELECT DISTINCT a '(a)' FROM default.av_foo av_foo |
+--------------------------------------------------------------+