mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-11-23 08:02:02 +00:00
b6dc721e33
$ gg -e 'numbers(toUInt64' -e 'numbers_mt(toUInt64' | cut -d: -f1 | sort -u | xargs sed -i -E 's#numbers(_mt|)\(toUInt64\(([^()]*)\)\)#numbers\1(\2)#'
10 lines
398 B
SQL
10 lines
398 B
SQL
-- for small cardinality the 64 bit hash perform worse, but for 1e10:
|
|
-- 4 byte hash: 2.8832809652e10
|
|
-- 8 byte hash: 0.9998568925e10
|
|
-- but hence checking with 1e10 values takes too much time (~45 secs), this
|
|
-- test is just to ensure that the result is different (and to document the
|
|
-- outcome).
|
|
|
|
SELECT uniqCombined(number) FROM numbers(1e7);
|
|
SELECT uniqCombined64(number) FROM numbers(1e7);
|