CREATE INDEX gives: ERROR: pgvecto.rs: The index is already existing in the background worker.

[ergo70]

Hello,

PostgreSQL 16.2 on Ubuntu 22.04.3 LTS. pgvector.rs binary release 0.2.1. psql CLI.

CREATE TABLE items (
id int4 GENERATED ALWAYS AS IDENTITY,
embedding vector(5) NOT NULL
);

INSERT INTO items (embedding) VALUES ('[1,2,3,4,5]');

CREATE INDEX ON items USING vectors (embedding vector_cos_ops);

ERROR: pgvecto.rs: The index is already existing in the background worker.

How can the INDEX already exist when I just tried to create it?

What am I doing wrong? Or is this a bug?

best regards

Ernst-Georg

[VoVAllen]

Have you run the create index before? It's a bit weird. Can you try restarting the database to see whether the issue still exists?

[ergo70]

I have stopped the server, removed the data directory and set up a completely fresh cluster with:

./initdb -k -D ../data/ -E UTF8 --no-locale -U postgres -W

My postgresql.auto.conf:

# Do not edit this file manually!
# It will be overwritten by the ALTER SYSTEM command.
shared_preload_libraries = 'vectors.so'
search_path = '"$user", public, vectors'

The error persists.

[VoVAllen]

Can you try remove all the file under pgdata/pg_vectors?

[ergo70]

As said before, I started with a empty, freshly initialized $PGDATA directory. However, I think I have found a way to reproduce it:

postgres=# CREATE TABLE items (
                id int4 GENERATED ALWAYS AS IDENTITY,
                embedding vector(5) NOT NULL
            );
postgres=# insert into items (embedding) values ('[1,2,3,4,5]');
INSERT 0 1
postgres=# CREATE INDEX ON items USING vectors (embedding vector_cos_ops);
CREATE INDEX

No problems.

postgres=# drop table items;
DROP TABLE
postgres=# CREATE UNLOGGED TABLE items (
                id int4 GENERATED ALWAYS AS IDENTITY,
                embedding vector(5) NOT NULL
            );
postgres=# insert into items (embedding) values ('[1,2,3,4,5]');
INSERT 0 1
postgres=# CREATE INDEX ON items USING vectors (embedding vector_cos_ops);
ERROR:  pgvecto.rs: The index is already existing in the background worker.

It's the UNLOGGED.

Since UNLOGGED is a supported directive for CREATE TABLE since PostgreSQL v9.1 (https://www.postgresql.org/docs/9.1/sql-createtable.html) I'd say, this is a bug. Or is it documented behavior?

best regards

Ernst-Georg

[usamoi]

It's intended behavior in 0.2.x. It's solved in #414 and it will work in 0.3.0.