Re: GIN Index for low cardinality
От | Олег Самойлов |
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Тема | Re: GIN Index for low cardinality |
Дата | |
Msg-id | 3E50E972-7451-4B86-95EF-33A9C2B777FB@ya.ru обсуждение исходный текст |
Ответ на | GIN Index for low cardinality (Ravi Krishna <srkrishna1@aol.com>) |
Ответы |
Re: GIN Index for low cardinality
Re: GIN Index for low cardinality |
Список | pgsql-general |
17 окт. 2018 г., в 13:46, Ravi Krishna <srkrishna1@aol.com> написал(а):In 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.
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