what is the benefit of LowCardinaliy?

[zdyj3170101136]

if i have a column

    env LowCardinality(String)

i could use proto.LowCardinaliy[proto.Str] and proto.Str to insert the column.

the LowCardinaliy would reduce bytes sent to clickhouse server but increase client memory usage.

in fact, if env is too slow that have only 2~3 bytes and the batch is very large, the LowCardinaliy index would too long that could not reduce too much memory.

is it have any other benefit?

[serprex]

I assume #425 reflects fix related to this issue you're raising?