perfschema 5.6.24

including the big commit
  commit 305130361bf72726de220f3d2b2787395e10be61
  Author: Marc Alff <marc.alff@oracle.com>
  Date:   Tue Feb 10 11:31:32 2015 +0100

      WL#8354 BACKPORT DIGEST IMPROVEMENTS TO MYSQL 5.6

(with the following commits) and related changes in sql/

sql/sql_digest.h

@@ -0,0 +1,130 @@
+/* Copyright (c) 2008, 2015, 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,
+  51 Franklin Street, Suite 500, Boston, MA 02110-1335 USA */
+
+#ifndef SQL_DIGEST_H
+#define SQL_DIGEST_H
+
+#include <string.h>
+class String;
+#include "my_md5.h"
+
+#define MAX_DIGEST_STORAGE_SIZE (1024*1024)
+
+/**
+  Structure to store token count/array for a statement
+  on which digest is to be calculated.
+*/
+struct sql_digest_storage
+{
+  bool m_full;
+  uint m_byte_count;
+  unsigned char m_md5[MD5_HASH_SIZE];
+  /** Character set number. */
+  uint m_charset_number;
+  /**
+    Token array.
+    Token array is an array of bytes to store tokens received during parsing.
+    Following is the way token array is formed.
+    ... &lt;non-id-token&gt; &lt;non-id-token&gt; &lt;id-token&gt; &lt;id_len&gt; &lt;id_text&gt; ...
+    For Example:
+    SELECT * FROM T1;
+    &lt;SELECT_TOKEN&gt; &lt;*&gt; &lt;FROM_TOKEN&gt; &lt;ID_TOKEN&gt; &lt;2&gt; &lt;T1&gt;
+  */
+  unsigned char *m_token_array;
+  /* Length of the token array to be considered for DIGEST_TEXT calculation. */
+  uint m_token_array_length;
+
+  sql_digest_storage()
+  {
+    reset(NULL, 0);
+  }
+
+  inline void reset(unsigned char *token_array, uint length)
+  {
+    m_token_array= token_array;
+    m_token_array_length= length;
+    reset();
+  }
+
+  inline void reset()
+  {
+    m_full= false;
+    m_byte_count= 0;
+    m_charset_number= 0;
+    if (m_token_array_length > 0)
+    {
+      memset(m_token_array, 0, m_token_array_length);
+    }
+    memset(m_md5, 0, MD5_HASH_SIZE);
+  }
+
+  inline bool is_empty()
+  {
+    return (m_byte_count == 0);
+  }
+
+  inline void copy(const sql_digest_storage *from)
+  {
+    /*
+      Keep in mind this is a dirty copy of something that may change,
+      as the thread producing the digest is executing concurrently,
+      without any lock enforced.
+    */
+    uint byte_count_copy= m_token_array_length < from->m_byte_count ?
+                          m_token_array_length : from->m_byte_count;
+
+    if (byte_count_copy > 0)
+    {
+      m_full= from->m_full;
+      m_byte_count= byte_count_copy;
+      m_charset_number= from->m_charset_number;
+      memcpy(m_token_array, from->m_token_array, m_byte_count);
+      memcpy(m_md5, from->m_md5, MD5_HASH_SIZE);
+    }
+    else
+    {
+      m_full= false;
+      m_byte_count= 0;
+      m_charset_number= 0;
+    }
+  }
+};
+typedef struct sql_digest_storage sql_digest_storage;
+
+/**
+  Compute a digest hash.
+  @param digest_storage The digest
+  @param [out] md5 The computed digest hash. This parameter is a buffer of size @c MD5_HASH_SIZE.
+*/
+void compute_digest_md5(const sql_digest_storage *digest_storage, unsigned char *md5);
+
+/**
+  Compute a digest text.
+  A 'digest text' is a textual representation of a query,
+  where:
+  - comments are removed,
+  - non significant spaces are removed,
+  - literal values are replaced with a special '?' marker,
+  - lists of values are collapsed using a shorter notation
+  @param digest_storage The digest
+  @param [out] digest_text
+  @param digest_text_length Size of @c digest_text.
+  @param [out] truncated true if the text representation was truncated
+*/
+void compute_digest_text(const sql_digest_storage *digest_storage,
+                         String *digest_text);
+
+#endif
+