Can I store vectors with different dimensions in the same column? You’ll need to use dimensionality reduction at the moment. What if I want to index vectors with more than 2,000 dimensions? Yes, pgvector uses the write-ahead log (WAL), which allows for replication and point-in-time recovery. A partitioned table can have thousands of partitions of that size. Languageįrequently Asked Questions How many vectors can be stored in a single table?Ī non-partitioned table has a limit of 32 TB by default in Postgres. You can even generate and store vectors in one language and query them in another. Use pgvector from any language with a Postgres client. When querying, specify an appropriate number of probes (higher is better for recall, lower is better for speed) - a good place to start is sqrt(lists)Īdd an index for each distance function you want to use.ĬREATE INDEX ON items USING ivfflat (embedding vector_l2_ops) WITH (lists = 1000) Languages.Choose an appropriate number of lists - a good place to start is rows / 1000 for up to 1M rows and sqrt(rows) for over 1M rows.Create the index after the table has some data.It has faster build times and uses less memory than HNSW, but has lower query performance (in terms of speed-recall tradeoff). Unlike typical indexes, you will see different results for queries after adding an approximate index.Īn IVFFlat index divides vectors into lists, and then searches a subset of those lists that are closest to the query vector. You can add an index to use approximate nearest neighbor search, which trades some recall for speed. SELECT category_id, AVG(embedding) FROM items GROUP BY category_id Indexingīy default, pgvector performs exact nearest neighbor search, which provides perfect recall.
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