Fix version check for system.tables.comment column in DatabaseMetaData.getTables

[ebyhr]

comment column doesn't exist in system.tables when version < 21.6 as far as I confirmed.

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[github-actions]

Benchmark                                 (client)  (connection)  (statement)  (type)   Mode  Cnt     Score     Error  Units
Basic.insertOneRandomNumber  clickhouse-http-jdbc1         reuse       normal  object  thrpt   20   216.602 ±  37.878  ops/s
Basic.insertOneRandomNumber  clickhouse-http-jdbc1         reuse     prepared  object  thrpt   20   207.206 ±  34.852  ops/s
Basic.insertOneRandomNumber  clickhouse-http-jdbc1           new       normal  object  thrpt   20   204.133 ±  31.842  ops/s
Basic.insertOneRandomNumber  clickhouse-http-jdbc1           new     prepared  object  thrpt   20   210.109 ±  27.430  ops/s
Basic.insertOneRandomNumber   clickhouse-grpc-jdbc         reuse       normal  object  thrpt   20   220.991 ±  28.598  ops/s
Basic.insertOneRandomNumber   clickhouse-grpc-jdbc         reuse     prepared  object  thrpt   20   221.218 ±  22.607  ops/s
Basic.insertOneRandomNumber   clickhouse-grpc-jdbc           new       normal  object  thrpt   20   226.458 ±  39.064  ops/s
Basic.insertOneRandomNumber   clickhouse-grpc-jdbc           new     prepared  object  thrpt   20   220.125 ±  29.708  ops/s
Basic.selectOneRandomNumber  clickhouse-http-jdbc1         reuse       normal  object  thrpt   20  1551.765 ± 108.056  ops/s
Basic.selectOneRandomNumber  clickhouse-http-jdbc1         reuse     prepared  object  thrpt   20  1540.131 ± 116.452  ops/s
Basic.selectOneRandomNumber  clickhouse-http-jdbc1           new       normal  object  thrpt   20  1529.126 ± 108.486  ops/s
Basic.selectOneRandomNumber  clickhouse-http-jdbc1           new     prepared  object  thrpt   20  1594.849 ± 104.308  ops/s
Basic.selectOneRandomNumber   clickhouse-grpc-jdbc         reuse       normal  object  thrpt   20   896.702 ± 115.974  ops/s
Basic.selectOneRandomNumber   clickhouse-grpc-jdbc         reuse     prepared  object  thrpt   20   976.365 ±  88.081  ops/s
Basic.selectOneRandomNumber   clickhouse-grpc-jdbc           new       normal  object  thrpt   20   887.432 ± 100.878  ops/s
Basic.selectOneRandomNumber   clickhouse-grpc-jdbc           new     prepared  object  thrpt   20   919.982 ± 113.887  ops/s

[zhicwu]

Thank you @ebyhr for fixing the issue. I'll look into this tonight and add unit tests to validate.

[github-actions]

Benchmark                                 (client)  (connection)  (statement)  (type)   Mode  Cnt     Score     Error  Units
Basic.insertOneRandomNumber  clickhouse-http-jdbc1         reuse       normal  object  thrpt   20   223.079 ±  27.513  ops/s
Basic.insertOneRandomNumber  clickhouse-http-jdbc1         reuse     prepared  object  thrpt   20   212.970 ±  27.042  ops/s
Basic.insertOneRandomNumber  clickhouse-http-jdbc1           new       normal  object  thrpt   20   210.342 ±  23.657  ops/s
Basic.insertOneRandomNumber  clickhouse-http-jdbc1           new     prepared  object  thrpt   20   210.162 ±  23.620  ops/s
Basic.insertOneRandomNumber   clickhouse-grpc-jdbc         reuse       normal  object  thrpt   20   221.491 ±  25.059  ops/s
Basic.insertOneRandomNumber   clickhouse-grpc-jdbc         reuse     prepared  object  thrpt   20   216.111 ±  24.659  ops/s
Basic.insertOneRandomNumber   clickhouse-grpc-jdbc           new       normal  object  thrpt   20   218.295 ±  25.104  ops/s
Basic.insertOneRandomNumber   clickhouse-grpc-jdbc           new     prepared  object  thrpt   20   221.770 ±  23.314  ops/s
Basic.selectOneRandomNumber  clickhouse-http-jdbc1         reuse       normal  object  thrpt   20  1181.396 ±  89.684  ops/s
Basic.selectOneRandomNumber  clickhouse-http-jdbc1         reuse     prepared  object  thrpt   20  1179.620 ±  98.324  ops/s
Basic.selectOneRandomNumber  clickhouse-http-jdbc1           new       normal  object  thrpt   20  1152.621 ± 103.287  ops/s
Basic.selectOneRandomNumber  clickhouse-http-jdbc1           new     prepared  object  thrpt   20  1181.857 ±  80.827  ops/s
Basic.selectOneRandomNumber   clickhouse-grpc-jdbc         reuse       normal  object  thrpt   20   683.453 ±  44.242  ops/s
Basic.selectOneRandomNumber   clickhouse-grpc-jdbc         reuse     prepared  object  thrpt   20   745.859 ±  80.596  ops/s
Basic.selectOneRandomNumber   clickhouse-grpc-jdbc           new       normal  object  thrpt   20   710.754 ±  68.312  ops/s
Basic.selectOneRandomNumber   clickhouse-grpc-jdbc           new     prepared  object  thrpt   20   780.656 ±  69.958  ops/s