src/gausskernel/dbmind/kernel/hypopg_index.cpp

@@ -17,6 +17,21 @@
  *
  * -------------------------------------------------------------------------
  */
+
+
+/*
+In PG database, if you check whether an index contributes to one or more queries,
+HypoPG can play a key role. It is an extension of postgresql, which allows you to create 
+virtual indexes and observe whether the optimizer is used. Therefore, you can provide methods
+for which queries need to be optimized and which indexes you want to try. So for the average user,
+how to better judge whether indexing is effective or not? Virtual index is a very useful thing, with no
+side effects. It is just a virtual index. After establishing a virtual index, you can check the COST estimate
+after adding the index through EXPLAIN to judge whether the cost will be reduced. In addition, the hypothetica
+l index HypoPG will create is not stored in any directory, but in the connection private memory. Therefore, it
+will not inflate any tables, nor will it affect any concurrent connections. Because it is assumed that indexes 
+don't really exist, HypoPG ensures that they will only be used with a simple EXPLAIN statement (no ANALYZE option).
+
+*/
 #include <unistd.h>
 #include <math.h>
 #include "postgres.h"