2.5 KiB
vec0
idxStr
The vec0 idxStr is a string composed of single "header" character and 0 or
more "blocks" of 4 characters each.
The "header" charcter denotes the type of query plan, as determined by the
enum vec0_query_plan values. The current possible values are:
| Name | Value | Description |
|---|---|---|
VEC0_QUERY_PLAN_FULLSCAN |
'1' |
Perform a full-scan on all rows |
VEC0_QUERY_PLAN_POINT |
'2' |
Perform a single-lookup point query for the provided rowid |
VEC0_QUERY_PLAN_KNN |
'3' |
Perform a KNN-style query on the provided query vector and parameters. |
Each 4-character "block" is associated with a corresponding value in argv[]. For example, the 1st block at byte offset 1-4 (inclusive) is the 1st block and is associated with argv[1]. The 2nd block at byte offset 5-8 (inclusive) is associated with argv[2] and so on. Each block describes what kind of value or filter the given argv[i] value is.
VEC0_IDXSTR_KIND_KNN_MATCH ('{')
argv[i] is the query vector of the KNN query.
The remaining 3 characters of the block are _ fillers.
VEC0_IDXSTR_KIND_KNN_K ('}')
argv[i] is the limit/k value of the KNN query.
The remaining 3 characters of the block are _ fillers.
VEC0_IDXSTR_KIND_KNN_ROWID_IN ('[')
argv[i] is the optional rowid in (...) value, and must be handled with sqlite3_vtab_in_first() /
sqlite3_vtab_in_next().
The remaining 3 characters of the block are _ fillers.
VEC0_IDXSTR_KIND_KNN_PARTITON_CONSTRAINT (']')
argv[i] is a "constraint" on a specific partition key.
The second character of the block denotes which partition key to filter on, using A to denote the first partition key column, B for the second, etc. It is encoded with 'A' + partition_idx and can be decoded with c - 'A'.
The third character of the block denotes which operator is used in the constraint. It will be one of the values of enum vec0_partition_operator, as only a subset of operations are supported on partition keys.
The fourth character of the block is a _ filler.
VEC0_IDXSTR_KIND_POINT_ID ('!')
argv[i] is the value of the rowid or id to match against for the point query.
The remaining 3 characters of the block are _ fillers.