executor: show CARTESIAN Join explicitly in the results of Explain

[qw4990]

What problem does this PR solve?

Show the keyword CARTESIAN if a Join operation is a cartesian join in the results of Explain.

After this PR:

mysql> explain select * from t t1, t t2 where t1.k1>t2.k1;
+------------------------+-------+------+-----------------------------------------------------------------------------------+
| id                     | count | task | operator info                                                                     |
+------------------------+-------+------+-----------------------------------------------------------------------------------+
| HashLeftJoin_8         | 1.00  | root | CARTESIAN inner join, inner:IndexReader_13, other cond:gt(test.t1.k1, test.t2.k1) |
| ├─IndexReader_11       | 1.00  | root | index:IndexScan_10                                                                |
| │ └─IndexScan_10       | 1.00  | cop  | table:t1, index:k1, k2, range:[-inf,+inf], keep order:false, stats:pseudo         |
| └─IndexReader_13       | 1.00  | root | index:IndexScan_12                                                                |
|   └─IndexScan_12       | 1.00  | cop  | table:t2, index:k1, k2, range:[-inf,+inf], keep order:false, stats:pseudo         |
+------------------------+-------+------+-----------------------------------------------------------------------------------+

What is changed and how it works?

1. Use equal conditions in a Join to judge if it is a cartesian join;
2. Update some unit tests and explain tests;

Check List

Tests

• Unit test

[alivxxx]

LGTM

[zz-jason]

LGTM

[sre-bot]

/run-all-tests

[codecov]

Codecov Report

Merging #11415 into master will not change coverage.
The diff coverage is n/a.

@@             Coverage Diff             @@
##             master     #11415   +/-   ##
===========================================
  Coverage   81.4028%   81.4028%           
===========================================
  Files           424        424           
  Lines         90799      90799           
===========================================
  Hits          73913      73913           
  Misses        11579      11579           
  Partials       5307       5307

[sre-bot]

success

[sre-bot]

/run-all-tests

[sre-bot]

@qw4990 merge failed.

[qw4990]

/run-unit-test

[qw4990]

/run-integration-common-test

[sre-bot]

cherry pick to release-3.0 failed