Vector Search feature needs to support creating vector indexes with additional
filtering column. There will be two types of indexes: global which indexes
vectors per table, and local which indexes vectors per partition key. The new
syntaxes are based on ScyllaDB's Global Secondary Index and Local Secondary
Index. Vector indexes don't use secondary indexes functionalities in any way -
all indexing, filtering and processing data will be done on Vector Store side.
This patch allows creating vector indexes using this CQL syntax:
```
CREATE TABLE IF NOT EXISTS cycling.comments_vs (
commenter text,
comment text,
comment_vector VECTOR <FLOAT, 5>,
created_at timestamp,
discussion_board_id int,
country text,
lang text,
PRIMARY KEY ((commenter, discussion_board_id), created_at)
);
CREATE CUSTOM INDEX IF NOT EXISTS global_ann_index
ON cycling.comments_vs(comment_vector, country, lang) USING 'vector_index'
WITH OPTIONS = { 'similarity_function': 'DOT_PRODUCT' };
CREATE CUSTOM INDEX IF NOT EXISTS local_ann_index
ON cycling.comments_vs((commenter, discussion_board_id), comment_vector, country, lang)
USING 'vector_index'
WITH OPTIONS = { 'similarity_function': 'DOT_PRODUCT' };
```
Currently, if we run these queries to create indexes we will receive such errors:
```
InvalidRequest: Error from server: code=2200 [Invalid query] message="Vector index can only be created on a single column"
InvalidRequest: Error from server: code=2200 [Invalid query] message="Local index definition must contain full partition key only. Redundant column: XYZ"
```
This commit refactors `vector_index::check_target` to correctly validate
columns building the index. Vector-store currently support filtering by native
types, so the type of columns is checked. The first column from the list must
be a vector (to build index based on these vectors), so it is also checked.
Allowed types for columns are native types without counter (it is not possible
to create a table with counter and vector) and without duration (it is not
possible to correctly compare durations, this type is even not allowed in
secondary indexes).
This commits adds cqlpy test to check errors while creating indexes.
Fixes: SCYLLADB-298
This needs to be backported to version 2026.1 as this is a fix for filtering support.
Closesscylladb/scylladb#28366