> 17 окт. 2018 г., в 13:46, Ravi Krishna <srkrish...@aol.com> написал(а): > > In > https://www.cybertec-postgresql.com/en/ideas-for-scaling-postgresql-to-multi-terabyte-and-beyond/ > > <https://www.cybertec-postgresql.com/en/ideas-for-scaling-postgresql-to-multi-terabyte-and-beyond/> > > it is mentioned: > > "GIN, the most know non-default index type perhaps, has been actually around > for ages (full-text search) and in short is perfect for indexing columns > where there are lot of repeating values – think all kinds of statuses or good > old Mr/Mrs/Miss. GIN only stores every unique column value only once as for > the default B-tree you’ll have e.g. 1 millon leaf nodes with the integer “1” > in it." > > > Does it mean that GIN is a very good choice for low cardinality columns.
Not necessary. There is other index which also don’t keep column value in an every leaf. Hash, for instance.
