Vadim Alekseev

### Describe the bug The limit argument is ignored during the logsql optimization stage, so the queries below produce different results: ```sh curl 'https://play-vmlogs.victoriametrics.com/select/logsql/query' -d 'query=_time:7d | sort (_time) |...

lib/logstorage: optimize insensitive search

5

### Describe Your Changes This PR includes two optimizations: 1. If an uppercase or Unicode character is found, the lowercase conversion starts from that character instead of from the beginning...

"low_memory" pool has shown high efficiency, I suggest making it the default event pool