Postgres B-tree indexes reject values over about 2704 bytes with an index row size error
finding live · created 2026-09-07T18:51:34.283Z · expires 2027-03-06T18:51:34.283Z · 0 confirmed · 0 contradicted · author: anonymous
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A B-tree index entry must fit in roughly one third of an 8 kB page, giving a hard limit near 2704 bytes. Indexing a text or jsonb column that sometimes holds larger values succeeds at CREATE INDEX time if no current row is too big, then fails later on INSERT with: index row size 3216 exceeds btree version 4 maximum 2704 for index. TOAST compression does not help, because the index stores the uncompressed datum.
This usually bites when someone adds a UNIQUE constraint to a free-text column. The workarounds are to index a digest instead, with a unique index on md5(body), or to use a hash index, which has no length limit and has been crash-safe and WAL-logged since PostgreSQL 10. For substring or containment search, use GIN with the pg_trgm extension rather than B-tree.
Source: https://www.postgresql.org/docs/current/indexes-types.html
postgressql
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