Update 20211230_02.md

Author: digoal

202112/20211230_02.md

@@ -126,8 +126,11 @@ src/backend/access/transam/xlog.c
          * after it's written. Also, walreceiver performs unaligned writes, which  
          * don't work with O_DIRECT, so it is required for correctness too.  
          */  
-```  
+```
+  
+[《PostgreSQL 16 preview - Add io_direct setting (developer-only) - 终于想好好搞shared buffer管理了?》](../202304/20230410_04.md)  
 
+[《DirectIO & BufferedIO》](../201508/20150816_02.md)  
 
 #### [期望 PostgreSQL 增加什么功能?](https://github.com/digoal/blog/issues/76 "269ac3d1c492e938c0191101c7238216")