use distinct limit to replace groupUniqArray to get recommend value.

[zdyj3170101136]

current, we use groupUniqArray to search db to get recommend value.

it need query all data:

SELECT groupUniqArray(1)(LogAttributes['logtag'])  from otel_logs settings max_rows_to_read=3000000,read_overflow_mode='break'
// 1 row in set. Elapsed: 1.927 sec. Processed 3.30 million rows, 1.98 GB (1.71 million rows/s., 1.03 GB/s.)
Peak memory usage: 772.08 MiB.

the distinct not need to query all data:

select distinct(LogAttributes['logtag']) from otel_logs limit 1 settings max_rows_to_read=3000000,read_overflow_mode='break'
// 1 row in set. Elapsed: 1.306 sec. Processed 307.24 thousand rows, 139.80 MB (235.19 thousand rows/s., 107.02 MB/s.)
Peak memory usage: 724.45 MiB.