feat(fuse): add system$clustering_information function

[zhyass]

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Summary

mysql> create TABLE t(A int,  B int ) cluster by(B,A);
Query OK, 0 rows affected (0.05 sec)
Read 0 rows, 0.00 B in 0.006 sec., 0 rows/sec., 0.00 B/sec.

mysql> insert into t values(0,3),(1,1);
Query OK, 0 rows affected (0.03 sec)
Read 2 rows, 16.00 B in 0.011 sec., 175.4 rows/sec., 1.37 KiB/sec.

mysql> insert into t values(1,3),(2,1);
Query OK, 0 rows affected (0.06 sec)
Read 2 rows, 16.00 B in 0.012 sec., 165.46 rows/sec., 1.29 KiB/sec.

mysql> insert into t values(4,4) ;
Query OK, 0 rows affected (0.05 sec)
Read 1 rows, 8.00 B in 0.012 sec., 82.9 rows/sec., 663.20 B/sec.

mysql> call system$clustering_information('default','t')\G
*************************** 1. row ***************************
           cluster_by_keys: (B, A)
         total_block_count: 3
total_constant_block_count: 1
          average_overlaps: 0.6667
             average_depth: 1.6667
     block_depth_histogram: {"00001":1,"00002":2}
1 row in set (0.07 sec)
Read 0 rows, 0.00 B in 0.013 sec., 0 rows/sec., 0.00 B/sec.

Changelog

• New Feature

Related Issues

Fixes #5439

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1 Ignored Deployment

Name	Status	Preview	Updated
databend	⬜️ Ignored (Inspect)		May 20, 2022 at 4:20AM (UTC)

[mergify]

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[dantengsky]

/LGTM

[BohuTANG]

We can skip the test in cluster mode with a '_cluster' suffix new test file, let's run it only in the stand-alone mode.

[BohuTANG]

This error message is not stable with the at line 9:.
Can we set an ErrCode number for it? @zhang2014 @sundy-li

[sundy-li]

Why not use -- {ErrorCode 1002}

[BohuTANG]

The -- {ErrorCode 1002} should be set on the 09_0014_func_clustering_information_function.sql, but this test will not work with standalone.

[zhyass]

Let me comment out the case first, this bug will be fixed soon.

[BohuTANG]

This error message is not stable with the at line 9:.
Can we set an ErrCode number for it? @zhang2014 @sundy-li

[BohuTANG]

Let's merge first.