defrag: defrag both patricia key and variable size columns

GitHub: groongaGH-2168

Ensure defragmentation covers both keys and variable-size columns
in Patricia trees

Previously, the defragmentation process for Patricia trees only
targeted the keys, leaving variable-size columns untouched. This
change handles both the keys and the variable-size columns.

lib/db.c

@@ -14872,7 +14872,7 @@ grn_obj_defrag(grn_ctx *ctx, grn_obj *obj, int threshold)
   case GRN_TABLE_PAT_KEY:
     GRN_TABLE_LOCK_BEGIN(ctx, obj) { r = grn_pat_defrag(ctx, (grn_pat *)obj); }
     GRN_TABLE_LOCK_END(ctx);
-    break;
+    /* FALLTHROUGH */
   case GRN_TABLE_HASH_KEY:
   case GRN_TABLE_DAT_KEY:
   case GRN_TABLE_NO_KEY:

test/command/suite/defrag/combined/pat_and_var_size_column.expected

@@ -0,0 +1,101 @@
+table_create --name Users --flags TABLE_PAT_KEY --key_type ShortText
+[[0,0.0,0.0],true]
+column_create Users secret COLUMN_SCALAR ShortText
+[[0,0.0,0.0],true]
+delete Users --filter '_id == 2'
+[[0,0.0,0.0],true]
+object_inspect Users
+[
+  [
+    0,
+    0.0,
+    0.0
+  ],
+  {
+    "id": 256,
+    "name": "Users",
+    "type": {
+      "id": 49,
+      "name": "table:pat_key"
+    },
+    "key": {
+      "type": {
+        "id": 14,
+        "name": "ShortText",
+        "type": {
+          "id": 32,
+          "name": "type"
+        },
+        "size": 4096
+      },
+      "total_size": 36,
+      "max_total_size": 4294967294
+    },
+    "value": {
+      "type": null
+    },
+    "n_records": 3,
+    "disk_usage": 0
+  }
+]
+defrag Users
+[[0,0.0,0.0],true]
+#|w| segment_infos[1] = 2097160 after defrag
+object_inspect Users
+[
+  [
+    0,
+    0.0,
+    0.0
+  ],
+  {
+    "id": 256,
+    "name": "Users",
+    "type": {
+      "id": 49,
+      "name": "table:pat_key"
+    },
+    "key": {
+      "type": {
+        "id": 14,
+        "name": "ShortText",
+        "type": {
+          "id": 32,
+          "name": "type"
+        },
+        "size": 4096
+      },
+      "total_size": 27,
+      "max_total_size": 4294967294
+    },
+    "value": {
+      "type": null
+    },
+    "n_records": 3,
+    "disk_usage": 0
+  }
+]
+check Users
+[
+  [
+    0,
+    0.0,
+    0.0
+  ],
+  [
+    {
+      "flags": "0000C001",
+      "key size": 4096,
+      "value_size": 0,
+      "tokenizer": 0,
+      "normalizer": 0,
+      "n_entries": 3,
+      "curr_rec": 4,
+      "curr_key": 27,
+      "curr_del": 1,
+      "curr_del2": 0,
+      "curr_del3": 0,
+      "n_garbages": 1
+    }
+  ]
+]

test/command/suite/defrag/combined/pat_and_var_size_column.test

@@ -0,0 +1,22 @@
+# This is too slow with HTTP chunked.
+#@require-interface stdio
+
+table_create --name Users --flags TABLE_PAT_KEY --key_type ShortText
+column_create Users secret COLUMN_SCALAR ShortText
+
+# The 'secret' column stores large strings over 65536B, whicha are `SEQUENTIAL`
+# elements and stored in `SEQUENTIAL` segments. These segments will be
+# defragmentation targets.
+#@disable-logging
+#@generate-series 1 4 Users '{"_key" => "user-no-#{i}", "secret" => "#{"x" * (2 ** 20)}"}'
+#@enable-logging
+
+delete Users --filter '_id == 2'
+
+# After defragmentation, the total size of the PAT keys should decrease.
+# Additionally, defragmentation logs for the variable-size column should be
+# displayed.
+object_inspect Users
+defrag Users
+object_inspect Users
+check Users