Adding the function ps_thread_id() which returns the Performance Schema thread id for the connection id passed as an argument

Author: JesperWisborgKrogh

functions/ps_thread_id.sql

@@ -0,0 +1,60 @@
+/* Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; version 2 of the License.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
+
+DROP FUNCTION IF EXISTS ps_thread_id;
+
+CREATE DEFINER='root'@'localhost' FUNCTION ps_thread_id(
+        in_connection_id BIGINT UNSIGNED
+    ) RETURNS BIGINT UNSIGNED
+    COMMENT '
+             Description
+             -----------
+
+             Return the Performance Schema THREAD_ID for the specified connection ID.
+
+             Parameters
+             -----------
+
+             in_connection_id (BIGINT UNSIGNED):
+               The id of the connection to return the thread id for.
+
+             Example
+             -----------
+
+             mysql> SELECT sys.ps_thread_id(79);
+             +----------------------+
+             | sys.ps_thread_id(79) |
+             +----------------------+
+             |                   98 |
+             +----------------------+
+             1 row in set (0.00 sec)
+
+             mysql> SELECT sys.ps_thread_id(CONNECTION_ID());
+             +-----------------------------------+
+             | sys.ps_thread_id(CONNECTION_ID()) |
+             +-----------------------------------+
+             |                                98 |
+             +-----------------------------------+
+             1 row in set (0.00 sec)
+            '
+
+SQL SECURITY INVOKER
+NOT DETERMINISTIC
+READS SQL DATA
+    RETURN (SELECT THREAD_ID
+              FROM `performance_schema`.`threads`
+             WHERE PROCESSLIST_ID = in_connection_id
+           )
+;