fix: a set of incorrect behaviors (#430)

* fix: set amoptionalkey to false

Signed-off-by: usamoi <usamoi@outlook.com>

* fix: set returned value of aminsert to false

Signed-off-by: usamoi <usamoi@outlook.com>

* fix: forbid scanning with a non-MVCC-compliant snapshot

Signed-off-by: usamoi <usamoi@outlook.com>

* fix: pg_vector_index_stat

Signed-off-by: usamoi <usamoi@outlook.com>

* fix: printing info instead of throwing errors in amvalidate

Signed-off-by: usamoi <usamoi@outlook.com>

* fix: revert set amoptionalkey to false

Signed-off-by: usamoi <usamoi@outlook.com>

---------

Signed-off-by: usamoi <usamoi@outlook.com>

crates/base/src/index.rs

@@ -119,10 +119,10 @@ pub struct VectorOptions {
     #[validate(range(min = 1, max = 1_048_575))]
     #[serde(rename = "dimensions")]
     pub dims: u32,
-    #[serde(rename = "distance")]
-    pub d: DistanceKind,
     #[serde(rename = "vector")]
     pub v: VectorKind,
+    #[serde(rename = "distance")]
+    pub d: DistanceKind,
 }
 
 impl VectorOptions {

src/datatype/memory_bvecf32.rs

@@ -143,7 +143,11 @@ impl IntoDatum for BVecf32Output {
     }
 
     fn type_oid() -> Oid {
-        pgrx::wrappers::regtypein("vectors.bvector")
+        let namespace = pgrx::pg_catalog::PgNamespace::search_namespacename(c"vectors").unwrap();
+        let namespace = namespace.get().expect("pgvecto.rs is not installed.");
+        let t = pgrx::pg_catalog::PgType::search_typenamensp(c"bvector", namespace.oid()).unwrap();
+        let t = t.get().expect("pg_catalog is broken.");
+        t.oid()
     }
 }
 

src/datatype/memory_svecf32.rs

@@ -159,7 +159,11 @@ impl IntoDatum for SVecf32Output {
     }
 
     fn type_oid() -> Oid {
-        pgrx::wrappers::regtypein("vectors.svector")
+        let namespace = pgrx::pg_catalog::PgNamespace::search_namespacename(c"vectors").unwrap();
+        let namespace = namespace.get().expect("pgvecto.rs is not installed.");
+        let t = pgrx::pg_catalog::PgType::search_typenamensp(c"svector", namespace.oid()).unwrap();
+        let t = t.get().expect("pg_catalog is broken.");
+        t.oid()
     }
 }
 

src/datatype/memory_vecf16.rs

@@ -140,7 +140,11 @@ impl IntoDatum for Vecf16Output {
     }
 
     fn type_oid() -> Oid {
-        pgrx::wrappers::regtypein("vectors.vecf16")
+        let namespace = pgrx::pg_catalog::PgNamespace::search_namespacename(c"vectors").unwrap();
+        let namespace = namespace.get().expect("pgvecto.rs is not installed.");
+        let t = pgrx::pg_catalog::PgType::search_typenamensp(c"vecf16", namespace.oid()).unwrap();
+        let t = t.get().expect("pg_catalog is broken.");
+        t.oid()
     }
 }
 

src/datatype/memory_vecf32.rs

@@ -136,7 +136,11 @@ impl IntoDatum for Vecf32Output {
     }
 
     fn type_oid() -> Oid {
-        pgrx::wrappers::regtypein("vectors.vector")
+        let namespace = pgrx::pg_catalog::PgNamespace::search_namespacename(c"vectors").unwrap();
+        let namespace = namespace.get().expect("pgvecto.rs is not installed.");
+        let t = pgrx::pg_catalog::PgType::search_typenamensp(c"vector", namespace.oid()).unwrap();
+        let t = t.get().expect("pg_catalog is broken.");
+        t.oid()
     }
 }
 

src/datatype/memory_veci8.rs

@@ -200,7 +200,11 @@ impl IntoDatum for Veci8Output {
     }
 
     fn type_oid() -> Oid {
-        pgrx::wrappers::regtypein("vectors.veci8")
+        let namespace = pgrx::pg_catalog::PgNamespace::search_namespacename(c"vectors").unwrap();
+        let namespace = namespace.get().expect("pgvecto.rs is not installed.");
+        let t = pgrx::pg_catalog::PgType::search_typenamensp(c"veci8", namespace.oid()).unwrap();
+        let t = t.get().expect("pg_catalog is broken.");
+        t.oid()
     }
 }
 

src/error.rs

@@ -100,15 +100,6 @@ pgvecto.rs: Dimensions type modifier of a vector column is needed for building t
     }
 }
 
-pub fn bad_opclass() -> ! {
-    error!(
-        "\
-pgvecto.rs: Indexes can only be built on built-in distance functions.
-ADVICE: If you want pgvecto.rs to support more distance functions, \
-visit `https://github.com/tensorchord/pgvecto.rs/issues` and contribute your ideas."
-    );
-}
-
 pub fn bad_service_not_exist() -> ! {
     error!(
         "\

src/index/am.rs

@@ -44,22 +44,16 @@ const AM_HANDLER: pgrx::pg_sys::IndexAmRoutine = {
 
     am_routine.type_ = pgrx::pg_sys::NodeTag::T_IndexAmRoutine;
 
-    am_routine.amstrategies = 1;
-    am_routine.amsupport = 0;
-
-    am_routine.amcanorder = false;
     am_routine.amcanorderbyop = true;
-    am_routine.amcanbackward = false;
-    am_routine.amcanunique = false;
-    am_routine.amcanmulticol = false;
+
+    // Index access methods that set `amoptionalkey` to `false`
+    // must index all tuples, even if the first column is `NULL`.
+    // However, PostgreSQL does not generate a path if there is no
+    // index clauses, even if there is a `ORDER BY` clause.
+    // So we have to set it to `true` and set costs of every path
+    // for vector index scans without `ORDER BY` clauses a large number
+    // and throw errors if someone really wants such a path.
     am_routine.amoptionalkey = true;
-    am_routine.amsearcharray = false;
-    am_routine.amsearchnulls = false;
-    am_routine.amstorage = false;
-    am_routine.amclusterable = false;
-    am_routine.ampredlocks = false;
-    am_routine.amcaninclude = false;
-    am_routine.amkeytype = pgrx::pg_sys::InvalidOid;
 
     am_routine.amvalidate = Some(amvalidate);
     am_routine.amoptions = Some(amoptions);
@@ -82,8 +76,12 @@ const AM_HANDLER: pgrx::pg_sys::IndexAmRoutine = {
 
 #[pgrx::pg_guard]
 pub unsafe extern "C" fn amvalidate(opclass_oid: pgrx::pg_sys::Oid) -> bool {
-    am_setup::convert_opclass_to_distance(opclass_oid);
-    true
+    if am_setup::convert_opclass_to_vd(opclass_oid).is_some() {
+        pgrx::info!("Vector indexes can only be built on built-in operator classes.");
+        true
+    } else {
+        false
+    }
 }
 
 #[pgrx::pg_guard]
@@ -210,7 +208,7 @@ pub unsafe extern "C" fn aminsert(
     if let Some(v) = vector {
         am_update::update_insert(id, v, *heap_tid);
     }
-    true
+    false
 }
 
 #[pgrx::pg_guard]

src/index/am_scan.rs

@@ -64,6 +64,14 @@ pub unsafe fn next_scan(scan: pgrx::pg_sys::IndexScanDesc) -> bool {
     let scanner = &mut *((*scan).opaque as *mut Scanner);
     if let Scanner::Initial { vector } = scanner {
         if let Some(vector) = vector.as_ref() {
+            // https://www.postgresql.org/docs/current/index-locking.html
+            // If heap entries referenced physical pointers are deleted before
+            // they are consumed by PostgreSQL, PostgreSQL will received wrong
+            // physical pointers: no rows or irreverent rows are referenced.
+            if (*(*scan).xs_snapshot).snapshot_type != pgrx::pg_sys::SnapshotType_SNAPSHOT_MVCC {
+                pgrx::error!("scanning with a non-MVCC-compliant snapshot is not supported");
+            }
+
             let oid = (*(*scan).indexRelation).rd_id;
             let id = get_handle(oid);