Partial Index
Introduction Partial Index is an extremely powerful feature that allows the creation of an index on only a subset of a table's data, instead of indexing the entire table. This subset is defined by a filtering condition in a WHERE clause when creating the index. In essence, a Partial Index just adds a condition during index creation, so it can be used with all index types (such as B-Tree , Hash , GIN , GiST , ...) and supports all data types. Additionally, a Partial Index can also be used in combination with a Constraint , Expression Index and Composite Index . Advantages Space-saving: The index size is much smaller than a Full Index, which saves RAM and disk space. Increased Write performance (INSERT/UPDATE/DELETE): When adding or modifying data that does not satisfy the index condition, Postgres does not need to update the index tree. Disadvantages Queries must match the condition: The Postgres Query Planner only uses this index if the SELECT query has a WHERE clause that exactl...