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Use VECTOR.CREATE to create a vector index at a key. DIM fixes the number of elements every vector in the index must have, and METRIC fixes how similarity between two vectors is measured. Both are permanent: they decide how the index is built, so they cannot be changed afterwards, and a vector whose length does not match DIM is rejected at write time. Pick COSINE when only the direction of the embedding matters, which is the usual choice for text embeddings, DOT when magnitude carries meaning, and EUCLIDEAN when straight-line distance in the embedding space does. The index occupies its key like any other Redis value, so EXISTS, EXPIRE, and DEL work on it, and creating one at a key already used by another type fails. EXISTSOK makes the command succeed instead of failing when the index is already there, which keeps a start-up path idempotent; a mismatch in dimension or metric is still an error. Vector indexes are an Upstash extension. See the vector command overview for how an index is created, written to, and queried.

Syntax

Arguments

Important points

  • DIM and METRIC are both required and cannot be changed after the index is created. Use VECTOR.DROP and create it again to change either.
  • Without EXISTSOK, creating an index that already exists returns ERR Index <index> already exists.
  • With EXISTSOK, an existing index with a different dimension or metric returns ERR Index <index> already exists with a different configuration.

Response

The reply reports the result of the operation. Error replies have the same shape in RESP2 and RESP3 and are surfaced as exceptions by the SDKs below.
Client libraries often decode bulk strings, maps, sets, and numeric strings into language-native values. The table describes the Redis wire reply.

Examples

TCP examples use the TLS REDIS_URL from the Upstash console. REST examples use UPSTASH_REDIS_REST_URL and UPSTASH_REDIS_REST_TOKEN.
This command is not supported yet in @upstash/redis.
This command is not supported yet in upstash_redis.