feat(pg_catalog): stub pg_opclass (#6167)

* stub pg_opclass

* fix typo

* fix

* fix review

Author: kwannoel

e2e_test/batch/catalog/pg_opclass.slt.part

@@ -0,0 +1,13 @@
+query IITIIIIII
+SELECT
+    oid,
+    opcmethod,
+    opcname,
+    opcnamespace,
+    opcowner,
+    opcfamily,
+    opcintype,
+    opcdefault,
+    opckeytype
+FROM pg_catalog.pg_opclass;
+----

src/frontend/src/catalog/pg_catalog/mod.rs

@@ -17,6 +17,7 @@ pub mod pg_class;
 pub mod pg_index;
 pub mod pg_matviews_info;
 pub mod pg_namespace;
+pub mod pg_opclass;
 pub mod pg_type;
 pub mod pg_user;
 
@@ -40,6 +41,7 @@ use crate::catalog::pg_catalog::pg_class::*;
 use crate::catalog::pg_catalog::pg_index::*;
 use crate::catalog::pg_catalog::pg_matviews_info::*;
 use crate::catalog::pg_catalog::pg_namespace::*;
+use crate::catalog::pg_catalog::pg_opclass::*;
 use crate::catalog::pg_catalog::pg_type::*;
 use crate::catalog::pg_catalog::pg_user::*;
 use crate::catalog::system_catalog::SystemCatalog;
@@ -92,6 +94,7 @@ impl SysCatalogReader for SysCatalogReaderImpl {
             PG_USER_TABLE_NAME => self.read_user_info(),
             PG_CLASS_TABLE_NAME => self.read_class_info(),
             PG_INDEX_TABLE_NAME => self.read_index_info(),
+            PG_OPCLASS_TABLE_NAME => self.read_opclass_info(),
             _ => {
                 Err(ErrorCode::ItemNotFound(format!("Invalid system table: {}", table_name)).into())
             }
@@ -209,6 +212,11 @@ impl SysCatalogReaderImpl {
             .collect_vec())
     }
 
+    // FIXME(noel): Tracked by <https://github.com/risingwavelabs/risingwave/issues/3431#issuecomment-1164160988>
+    fn read_opclass_info(&self) -> Result<Vec<Row>> {
+        Ok(vec![])
+    }
+
     fn read_class_info(&self) -> Result<Vec<Row>> {
         let reader = self.catalog_reader.read_guard();
         let schemas = reader.iter_schemas(&self.auth_context.database)?;
@@ -390,6 +398,7 @@ pub(crate) static PG_CATALOG_MAP: LazyLock<HashMap<String, SystemCatalog>> = Laz
         PG_USER_TABLE_NAME.to_string() => def_sys_catalog!(5, PG_USER_TABLE_NAME, PG_USER_COLUMNS),
         PG_CLASS_TABLE_NAME.to_string() => def_sys_catalog!(6, PG_CLASS_TABLE_NAME, PG_CLASS_COLUMNS),
         PG_INDEX_TABLE_NAME.to_string() => def_sys_catalog!(7, PG_INDEX_TABLE_NAME, PG_INDEX_COLUMNS),
+        PG_OPCLASS_TABLE_NAME.to_string() => def_sys_catalog!(8, PG_OPCLASS_TABLE_NAME, PG_OPCLASS_COLUMNS),
     }
 });
 

src/frontend/src/catalog/pg_catalog/pg_opclass.rs

@@ -0,0 +1,32 @@
+// Copyright 2022 Singularity Data
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use risingwave_common::types::DataType;
+
+use crate::catalog::pg_catalog::PgCatalogColumnsDef;
+
+/// The catalog `pg_opclass` defines index access method operator classes.
+/// Reference: [`https://www.postgresql.org/docs/current/catalog-pg-opclass.html`].
+pub const PG_OPCLASS_TABLE_NAME: &str = "pg_opclass";
+pub const PG_OPCLASS_COLUMNS: &[PgCatalogColumnsDef<'_>] = &[
+    (DataType::Int32, "oid"),
+    (DataType::Int32, "opcmethod"),
+    (DataType::Varchar, "opcname"),
+    (DataType::Int32, "opcnamespace"),
+    (DataType::Int32, "opcowner"),
+    (DataType::Int32, "opcfamily"),
+    (DataType::Int32, "opcintype"),
+    (DataType::Int32, "opcdefault"),
+    (DataType::Int32, "opckeytype"),
+];