Support max_rows directive on table and view

sql/load_sql_context.sql

@@ -265,7 +265,8 @@ select
                                             )
                                         ),
                                         'primary_key_columns', d.directive -> 'primary_key_columns',
-                                        'foreign_keys', d.directive -> 'foreign_keys'
+                                        'foreign_keys', d.directive -> 'foreign_keys',
+                                        'max_rows', (d.directive ->> 'max_rows')::int
                                     )
                                 from
                                     directives d

src/builder.rs

@@ -1423,13 +1423,13 @@ where
                 }
             };
 
-            let max_rows: u64 = xtype
+            let max_rows = xtype
                 .schema
                 .context
                 .schemas
                 .values()
                 .find(|s| s.oid == xtype.table.schema_oid)
-                .map(|x| x.directives.max_rows)
+                .map(|schema| xtype.table.max_rows(schema))
                 .unwrap_or(30);
 
             let before: Option<Cursor> = read_argument_cursor(

src/sql_types.rs

@@ -482,6 +482,9 @@ pub struct TableDirectives {
     // @graphql({"primary_key_columns": ["id"]})
     pub primary_key_columns: Option<Vec<String>>,
 
+    // @graphql({"max_rows": 20})
+    pub max_rows: Option<u64>,
+
     /*
     @graphql(
       {
@@ -576,13 +579,22 @@ impl Table {
     pub fn is_any_column_selectable(&self) -> bool {
         self.columns.iter().any(|x| x.permissions.is_selectable)
     }
+
     pub fn is_any_column_insertable(&self) -> bool {
         self.columns.iter().any(|x| x.permissions.is_insertable)
     }
 
     pub fn is_any_column_updatable(&self) -> bool {
         self.columns.iter().any(|x| x.permissions.is_updatable)
     }
+
+    /// Get the effective max_rows value for this table.
+    /// If table-specific max_rows is set, use that.
+    /// Otherwise, fall back to schema-level max_rows.
+    /// If neither is set, use the global default(set in load_sql_context.sql)
+    pub fn max_rows(&self, schema: &Schema) -> u64 {
+        self.directives.max_rows.unwrap_or(schema.directives.max_rows)
+    }
 }
 
 #[derive(Deserialize, Clone, Debug, Eq, PartialEq, Hash)]

test/expected/max_rows_directive.out

@@ -60,4 +60,65 @@ begin;
  {"data": {"accountCollection": {"edges": [{"node": {"id": 1}}, {"node": {"id": 2}}, {"node": {"id": 3}}, {"node": {"id": 4}}, {"node": {"id": 5}}, {"node": {"id": 6}}, {"node": {"id": 7}}, {"node": {"id": 8}}, {"node": {"id": 9}}, {"node": {"id": 10}}, {"node": {"id": 11}}, {"node": {"id": 12}}, {"node": {"id": 13}}, {"node": {"id": 14}}, {"node": {"id": 15}}, {"node": {"id": 16}}, {"node": {"id": 17}}, {"node": {"id": 18}}, {"node": {"id": 19}}, {"node": {"id": 20}}, {"node": {"id": 21}}, {"node": {"id": 22}}, {"node": {"id": 23}}, {"node": {"id": 24}}, {"node": {"id": 25}}, {"node": {"id": 26}}, {"node": {"id": 27}}, {"node": {"id": 28}}, {"node": {"id": 29}}, {"node": {"id": 30}}, {"node": {"id": 31}}, {"node": {"id": 32}}, {"node": {"id": 33}}, {"node": {"id": 34}}, {"node": {"id": 35}}, {"node": {"id": 36}}, {"node": {"id": 37}}, {"node": {"id": 38}}, {"node": {"id": 39}}, {"node": {"id": 40}}]}}}
 (1 row)
 
+    -- table-specific max_rows
+    comment on table account is e'@graphql({"max_rows": 5})';
+    -- expect 5 rows on first page
+    select graphql.resolve($$
+      {
+        accountCollection {
+          edges {
+            node {
+              id
+            }
+          }
+        }
+      }
+    $$);
+                                                                        resolve                                                                        
+-------------------------------------------------------------------------------------------------------------------------------------------------------
+ {"data": {"accountCollection": {"edges": [{"node": {"id": 1}}, {"node": {"id": 2}}, {"node": {"id": 3}}, {"node": {"id": 4}}, {"node": {"id": 5}}]}}}
+(1 row)
+
+    -- view-specific max_rows
+    create view person as
+    select * from account;
+    comment on view person is e'@graphql({"primary_key_columns": ["id"], "max_rows": 3})';
+    -- expect 3 rows on first page
+    select graphql.resolve($$
+      {
+        personCollection {
+          edges {
+            node {
+              id
+            }
+          }
+        }
+      }
+    $$);
+                                                  resolve                                                   
+------------------------------------------------------------------------------------------------------------
+ {"data": {"personCollection": {"edges": [{"node": {"id": 1}}, {"node": {"id": 2}}, {"node": {"id": 3}}]}}}
+(1 row)
+
+    -- nested view with max_rows
+    create view parent as
+    select * from person;
+    comment on view parent is e'@graphql({"primary_key_columns": ["id"], "max_rows": 2})';
+    -- expect 2 rows on first page
+    select graphql.resolve($$
+      {
+        parentCollection {
+          edges {
+            node {
+              id
+            }
+          }
+        }
+      }
+    $$);
+                                        resolve                                        
+---------------------------------------------------------------------------------------
+ {"data": {"parentCollection": {"edges": [{"node": {"id": 1}}, {"node": {"id": 2}}]}}}
+(1 row)
+
 rollback;

test/sql/max_rows_directive.sql

@@ -52,4 +52,56 @@ begin;
       }
     $$);
 
+    -- table-specific max_rows
+    comment on table account is e'@graphql({"max_rows": 5})';
+
+    -- expect 5 rows on first page
+    select graphql.resolve($$
+      {
+        accountCollection {
+          edges {
+            node {
+              id
+            }
+          }
+        }
+      }
+    $$);
+
+    -- view-specific max_rows
+    create view person as
+    select * from account;
+    comment on view person is e'@graphql({"primary_key_columns": ["id"], "max_rows": 3})';
+
+    -- expect 3 rows on first page
+    select graphql.resolve($$
+      {
+        personCollection {
+          edges {
+            node {
+              id
+            }
+          }
+        }
+      }
+    $$);
+
+    -- nested view with max_rows
+    create view parent as
+    select * from person;
+    comment on view parent is e'@graphql({"primary_key_columns": ["id"], "max_rows": 2})';
+
+    -- expect 2 rows on first page
+    select graphql.resolve($$
+      {
+        parentCollection {
+          edges {
+            node {
+              id
+            }
+          }
+        }
+      }
+    $$);
+
 rollback;