MySQL 5.6.51にPLEASE句を実装するパッチ

please_clause_for_5651.patch

--- ./sql/sql_yacc.yy.orig	2021-01-05 19:19:59.000000000 +0900
+++ ./sql/sql_yacc.yy	2021-04-01 11:52:06.167953286 +0900
@@ -2,2 +2,3 @@
    Copyright (c) 2000, 2019, Oracle and/or its affiliates. All rights reserved.
+   Copyright (c) 2021, yoku0825. All rights reserved.
 
@@ -1570,2 +1571,3 @@
 %token  SSL_SYM
+%token  PLEASE_SYM                    /* yoku0825 */
 %token  STARTING
@@ -2083,4 +2085,12 @@
         | xa
+        | please
         ;
 
+please:
+          PLEASE_SYM statement
+          {
+            YYTHD->variables.is_pleased= true;
+          }
+        ;  
+
 deallocate:
--- ./sql/sql_parse.cc.orig	2021-01-05 19:19:59.000000000 +0900
+++ ./sql/sql_parse.cc	2021-04-01 14:14:16.605954893 +0900
@@ -1385,2 +1385,3 @@
       break;					// fatal error is set
+
     MYSQL_QUERY_START(thd->query(), thd->thread_id,
@@ -1389,2 +1390,3 @@
                       (char *) thd->security_ctx->host_or_ip);
+ 
     char *packet_end= thd->query() + thd->query_length();
@@ -1483,3 +1485,4 @@
       mysql_parse(thd, beginning_of_next_stmt, length, &parser_state);
-    }
+
+   }
 
@@ -1829,2 +1832,3 @@
     thd->send_kill_message();
+
   thd->protocol->end_statement();
@@ -6427,2 +6431,3 @@
   mysql_reset_thd_for_next_command(thd);
+  thd->variables.is_pleased= 0; /* yoku0825 */
 
@@ -6434,2 +6439,21 @@
 
+    /* yoku0825 */
+    if (!(thd->variables.is_pleased))
+    {
+      if (thd->variables.sql_mode & MODE_STRICT_PLEASE)
+      {
+        my_printf_error(490825, "Please add PLEASE clause. I don't run your query.", MYF(0));
+        error= 1;
+        DBUG_VOID_RETURN;
+      }
+      else
+      {
+        sleep(1);
+        push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
+                            490825,
+                            "Please add PLEASE clause for speedup MySQL. See https://sakaik.hateblo.jp/entry/20210401/mysql_please_clause_in_aprilfool");
+      }
+    }
+    /* yoku0825 */
+
     const char *found_semicolon= parser_state->m_lip.found_semicolon;
--- ./sql/sql_class.h.orig	2021-01-05 19:19:59.000000000 +0900
+++ ./sql/sql_class.h	2021-04-01 13:55:47.458828101 +0900
@@ -156,2 +156,3 @@
 #define MODE_NO_ENGINE_SUBSTITUTION     (MODE_HIGH_NOT_PRECEDENCE*2)
+#define MODE_STRICT_PLEASE              (MODE_NO_ENGINE_SUBSTITUTION*2)
 #define MODE_PAD_CHAR_TO_FULL_LENGTH    (ULL(1) << 31)
@@ -569,2 +570,4 @@
 
+  my_bool is_pleased; /* yoku0825 */
+
   double long_query_time_double;
--- ./sql/sys_vars.cc.orig	2021-01-05 19:19:59.000000000 +0900
+++ ./sql/sys_vars.cc	2021-04-01 14:19:46.438828823 +0900
@@ -2912,3 +2912,3 @@
   "NO_AUTO_CREATE_USER", "HIGH_NOT_PRECEDENCE", "NO_ENGINE_SUBSTITUTION",
-  "PAD_CHAR_TO_FULL_LENGTH",
+  "STRICT_PLEASE_MODE", "PAD_CHAR_TO_FULL_LENGTH",
   0
@@ -3400,2 +3400,8 @@
 
+/* yoku0825 */
+static Sys_var_mybool Sys_is_pleased(
+       "is_pleased", "yoku0825",
+       SESSION_VAR(is_pleased), NO_CMD_LINE, DEFAULT(FALSE));
+/* yoku0825 */
+
 static Sys_var_bit Sys_transaction_allow_batching(
--- ./sql/lex.h.orig	2021-01-05 19:19:59.000000000 +0900
+++ ./sql/lex.h	2021-04-01 11:46:05.186445098 +0900
@@ -559,2 +559,3 @@
   { "SSL",		SYM(SSL_SYM)},
+  { "PLEASE",		SYM(PLEASE_SYM)},
   { "START",		SYM(START_SYM)},

Could you also add a "HURRY UP!" one to increase speed of long queries ? it would be nice to reduce the query time of about 50% with that SQL command.
Thank you for you great patch !

@lefred

That's very good idea!
But I don't enough time to improve the feature, because I have only 3 hours April 1st in Japanese Standard Time!

See you next April 1st!! :D

How about some positive reinforcement? Instead of refusing to execute non-polite queries please double the execution speed of polite queries :)

RKajiyama told me an idea "multiply sleep time like a connection_control plugin".
I think this is great idea for "not refusing but slowdown for non-polite queries." ;)

https://twitter.com/RKajiyama/status/1377505078962057217