Answer
Indexes speed up reads by creating fast lookup structures. PostgreSQL supports B-tree, Hash, GIN, GiST, SP-GiST, and BRIN.
Quick Answer
Indexes speed up data retrieval by creating a sorted data structure (B-tree by default) on one or more columns. Without an index, PostgreSQL scans every row (seq scan). With an index, it jumps directly to matching rows (index scan). Tradeoff: faster reads but slower writes (index updated on every INSERT/UPDATE/DELETE). Index columns frequently used in WHERE, JOIN, and ORDER BY.
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SugharaIQ Editorial Team
Verified Answer
This answer has been peer-reviewed by industry experts holding senior engineering roles to ensure technical accuracy and relevance for modern interview standards.
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Source: SugharaIQ