NULLs in ClickHouse can hurt performance

When coming from relational databases, NULLs are the go-to for optional fields. Using them in ClickHouse can lead to unexpected and often unnoticeable performance degradation. This article explain why. PostgreSQL When using null values in PostgreSQL, you rarely notice any difference. In PG, columns are nullable by default and you can index them. Internally, each row in PostgreSQL has a bitmap that…