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|
# name : query_cache_with_comments.patch
# introduced : 11 or before
# maintainer : Oleg
#
#!!! notice !!!
# Any small change to this file in the main branch
# should be done or reviewed by the maintainer!
diff -ruN /dev/null b/patch_info/query_cache_enhance.patch
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ b/patch_info/query_cache_enhance.patch 2011-04-09 18:48:53.000000000 +0400
@@ -0,0 +1,15 @@
+File=query_cache_enhance.patch
+Name= query cache Percona's cumulative patch
+Version=1.0
+Author=Percona <info@percona.com>
+License=GPL
+Comment= 1) Add new status - Waiting on query cache mutex (status_wait_query_cache_mutex.patch)
+ 2) Remove comments from query (need for cache hit) (query_cache_with_comments.patch)
+ 3) Totally disable query cache (query_cache_totally_disable.info)
+2010-05 - First version avaliable (query_cache_with_comments.patch)
+2010-07 - First version avaliable (status_wait_query_cache_mutex.patch
+2010-07 - First version avaliable (query_cache_totally_disable.info)
+2010-07 - Fix crash (query_cache_with_comments.patch)
+2010-07 - Fix incorrect behavior diff (query_cache_with_comments.patch)
+2010-09 - Merge patches to one
+2010-11 - Ported to 5.5
diff -ruN a/sql/mysqld.cc b/sql/mysqld.cc
--- a/sql/mysqld.cc 2011-04-09 18:48:50.000000000 +0400
+++ b/sql/mysqld.cc 2011-04-09 18:48:53.000000000 +0400
@@ -903,6 +903,7 @@
#endif
#ifdef HAVE_QUERY_CACHE
ulong query_cache_min_res_unit= QUERY_CACHE_MIN_RESULT_DATA_SIZE;
+my_bool opt_query_cache_strip_comments= FALSE;
Query_cache query_cache;
#endif
#ifdef HAVE_SMEM
diff -ruN a/sql/mysqld.h b/sql/mysqld.h
--- a/sql/mysqld.h 2011-04-09 18:48:50.000000000 +0400
+++ b/sql/mysqld.h 2011-04-09 18:48:53.000000000 +0400
@@ -91,6 +91,7 @@
extern my_bool opt_log, opt_slow_log;
extern my_bool opt_backup_history_log;
extern my_bool opt_backup_progress_log;
+extern my_bool opt_query_cache_strip_comments;
extern ulonglong log_output_options;
extern ulong log_backup_output_options;
extern my_bool opt_log_queries_not_using_indexes;
diff -ruN /dev/null b/sql/query_strip_comments.h
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ b/sql/query_strip_comments.h 2011-04-09 18:48:53.000000000 +0400
@@ -0,0 +1,37 @@
+#ifndef _SQL_QUERY_STRIPC_COMMENTS_H_
+#define _SQL_QUERY_STRIPC_COMMENTS_H_
+#ifdef HAVE_QUERY_CACHE
+
+// implemented in sql_cache.cc
+class QueryStripComments
+{
+private:
+ QueryStripComments(const QueryStripComments&);
+ QueryStripComments& operator=(const QueryStripComments&);
+public:
+ QueryStripComments();
+ ~QueryStripComments();
+ void set(const char* a_query, uint a_query_length, uint a_additional_length);
+
+ char* query() { return buffer; }
+ uint query_length() { return length; }
+private:
+ void cleanup();
+private:
+ char* buffer;
+ uint length /*query length, not buffer length*/;
+ uint buffer_length;
+};
+class QueryStripComments_Backup
+{
+public:
+ QueryStripComments_Backup(THD* a_thd,QueryStripComments* qsc);
+ ~QueryStripComments_Backup();
+private:
+ THD* thd;
+ char* query;
+ uint length;
+};
+
+#endif // HAVE_QUERY_CACHE
+#endif // _SQL_QUERY_STRIPC_COMMENTS_H_
diff -ruN a/sql/sql_cache.cc b/sql/sql_cache.cc
--- a/sql/sql_cache.cc 2011-04-09 18:48:50.000000000 +0400
+++ b/sql/sql_cache.cc 2011-04-09 18:48:53.000000000 +0400
@@ -344,6 +344,181 @@
#include "probes_mysql.h"
#include "transaction.h"
+#include "query_strip_comments.h"
+
+QueryStripComments::QueryStripComments()
+{
+ buffer = 0;
+ length = 0;
+ buffer_length = 0;
+}
+QueryStripComments::~QueryStripComments()
+{
+ cleanup();
+}
+
+inline bool query_strip_comments_is_white_space(char c)
+{
+ return ((' ' == c) || ('\t' == c) || ('\r' == c) || ('\n' ==c ));
+}
+void QueryStripComments::set(const char* query, uint query_length, uint additional_length)
+{
+ uint new_buffer_length = query_length + additional_length;
+ if(new_buffer_length > buffer_length)
+ {
+ cleanup();
+ buffer = (char*)my_malloc(new_buffer_length,MYF(0));
+ }
+ uint query_position = 0;
+ uint position = 0;
+ // Skip whitespaces from begin
+ while((query_position < query_length) && query_strip_comments_is_white_space(query[query_position]))
+ {
+ ++query_position;
+ }
+ long int last_space = -1;
+ while(query_position < query_length)
+ {
+ char current = query[query_position];
+ bool insert_space = false; // insert space to buffer, (IMPORTANT) don't update query_position
+ switch(current)
+ {
+ case '\'':
+ case '"':
+ {
+ buffer[position++] = query[query_position++]; // copy current symbol
+ while(query_position < query_length)
+ {
+ if(current == query[query_position]) // found pair quote
+ {
+ break;
+ }
+ buffer[position++] = query[query_position++]; // copy current symbol
+ }
+ break;
+ }
+ case '/':
+ {
+ if(((query_position + 2) < query_length) && ('*' == query[query_position+1]) && ('!' != query[query_position+2]))
+ {
+ query_position += 2; // skip "/*"
+ do
+ {
+ if('*' == query[query_position] && '/' == query[query_position+1]) // check for "*/"
+ {
+ query_position += 2; // skip "*/"
+ insert_space = true;
+ break;
+ }
+ else
+ {
+ ++query_position;
+ }
+ }
+ while(query_position < query_length);
+ if(!insert_space)
+ {
+ continue;
+ }
+ }
+ break;
+ }
+ case '-':
+ {
+ if(query[query_position+1] == '-')
+ {
+ ++query_position; // skip "-", and go to search of "\n"
+ }
+ else
+ {
+ break;
+ }
+ }
+ case '#':
+ {
+ do
+ {
+ ++query_position; // skip current symbol (# or -)
+ if('\n' == query[query_position]) // check for '\n'
+ {
+ ++query_position; // skip '\n'
+ insert_space = true;
+ break;
+ }
+ }
+ while(query_position < query_length);
+ if(insert_space)
+ {
+ break;
+ }
+ else
+ {
+ continue;
+ }
+ }
+ default:
+ if(query_strip_comments_is_white_space(current))
+ {
+ insert_space = true;
+ ++query_position;
+ }
+ break; // make gcc happy
+ }
+ if(insert_space)
+ {
+ if((last_space + 1) != position)
+ {
+ last_space = position;
+ buffer[position++] = ' ';
+ }
+ }
+ else
+ {
+ buffer[position++] = query[query_position++];
+ }
+ }
+ while((0 < position) && query_strip_comments_is_white_space(buffer[position - 1]))
+ {
+ --position;
+ }
+ buffer[position] = 0;
+ length = position;
+}
+void QueryStripComments::cleanup()
+{
+ if(buffer)
+ {
+ my_free(buffer);
+ }
+ buffer = 0;
+ length = 0;
+ buffer_length = 0;
+}
+QueryStripComments_Backup::QueryStripComments_Backup(THD* a_thd,QueryStripComments* qsc)
+{
+ if(opt_query_cache_strip_comments)
+ {
+ thd = a_thd;
+ query = thd->query();
+ length = thd->query_length();
+ qsc->set(query,length,thd->db_length + 1 + QUERY_CACHE_FLAGS_SIZE);
+ thd->set_query(qsc->query(),qsc->query_length());
+ }
+ else
+ {
+ thd = 0;
+ query = 0;
+ length = 0;
+ }
+}
+QueryStripComments_Backup::~QueryStripComments_Backup()
+{
+ if(thd)
+ {
+ thd->set_query(query,length);
+ }
+}
+
#ifdef EMBEDDED_LIBRARY
#include "emb_qcache.h"
#endif
@@ -454,7 +629,12 @@
Query_cache_wait_state wait_state(thd, __func__, __FILE__, __LINE__);
DBUG_ENTER("Query_cache::try_lock");
+ const char* old_proc_info= thd->proc_info;
+ thd_proc_info(thd,"Waiting on query cache mutex");
mysql_mutex_lock(&structure_guard_mutex);
+ DBUG_EXECUTE_IF("status_wait_query_cache_mutex_sleep", {
+ sleep(5);
+ });
while (1)
{
if (m_cache_lock_status == Query_cache::UNLOCKED)
@@ -501,6 +681,7 @@
}
}
mysql_mutex_unlock(&structure_guard_mutex);
+ thd->proc_info = old_proc_info;
DBUG_RETURN(interrupt);
}
@@ -1274,6 +1455,8 @@
unlock();
DBUG_VOID_RETURN;
}
+ QueryStripComments *query_strip_comments = &(thd->query_strip_comments);
+ QueryStripComments_Backup backup(thd,query_strip_comments);
/* Key is query + database + flag */
if (thd->db_length)
@@ -1451,6 +1634,9 @@
Query_cache_block_table *block_table, *block_table_end;
ulong tot_length;
Query_cache_query_flags flags;
+ QueryStripComments *query_strip_comments = &(thd->query_strip_comments);
+ char *sql_backup = sql;
+ uint query_length_backup = query_length;
DBUG_ENTER("Query_cache::send_result_to_client");
/*
@@ -1472,21 +1658,103 @@
{
uint i= 0;
- /*
- Skip '(' characters in queries like following:
- (select a from t1) union (select a from t1);
- */
- while (sql[i]=='(')
- i++;
+ if(opt_query_cache_strip_comments)
+ {
+ /* Skip all comments and non-letter symbols */
+ uint& query_position = i;
+ char* query = sql;
+ while(query_position < query_length)
+ {
+ bool check = false;
+ char current = query[query_position];
+ switch(current)
+ {
+ case '/':
+ if(((query_position + 2) < query_length) && ('*' == query[query_position+1]) && ('!' != query[query_position+2]))
+ {
+ query_position += 2; // skip "/*"
+ do
+ {
+ if('*' == query[query_position] && '/' == query[query_position+1]) // check for "*/" (without space)
+ {
+ query_position += 2; // skip "*/" (without space)
+ break;
+ }
+ else
+ {
+ ++query_position;
+ }
+ }
+ while(query_position < query_length);
+ continue; // analyze current symbol
+ }
+ break;
+ case '-':
+ if(query[query_position+1] == '-')
+ {
+ ++query_position; // skip "-"
+ }
+ else
+ {
+ break;
+ }
+ case '#':
+ do
+ {
+ ++query_position; // skip current symbol
+ if('\n' == query[query_position]) // check for '\n'
+ {
+ ++query_position; // skip '\n'
+ break;
+ }
+ }
+ while(query_position < query_length);
+ continue; // analyze current symbol
+ case '\r':
+ case '\n':
+ case '\t':
+ case ' ':
+ case '(':
+ case ')':
+ break;
+ default:
+ check = true;
+ break; // make gcc happy
+ } // switch(current)
+ if(check)
+ {
+ if(query_position + 2 < query_length)
+ {
+ // cacheable
+ break;
+ }
+ else
+ {
+ DBUG_PRINT("qcache", ("The statement is not a SELECT; Not cached"));
+ goto err;
+ }
+ } // if(check)
+ ++query_position;
+ } // while(query_position < query_length)
+ }
+ else // if(opt_query_cache_strip_comments)
+ {
+ /*
+ Skip '(' characters in queries like following:
+ (select a from t1) union (select a from t1);
+ */
+ while (sql[i]=='(')
+ i++;
- /*
- Test if the query is a SELECT
- (pre-space is removed in dispatch_command).
+ } // if(opt_query_cache_strip_comments)
+ /*
+ Test if the query is a SELECT
+ (pre-space is removed in dispatch_command).
- First '/' looks like comment before command it is not
- frequently appeared in real life, consequently we can
- check all such queries, too.
- */
+ First '/' looks like comment before command it is not
+ frequently appeared in real life, consequently we can
+ check all such queries, too.
+ */
if ((my_toupper(system_charset_info, sql[i]) != 'S' ||
my_toupper(system_charset_info, sql[i + 1]) != 'E' ||
my_toupper(system_charset_info, sql[i + 2]) != 'L') &&
@@ -1521,6 +1789,12 @@
goto err_unlock;
Query_cache_block *query_block;
+ if(opt_query_cache_strip_comments)
+ {
+ query_strip_comments->set(sql, query_length, thd->db_length + 1 + QUERY_CACHE_FLAGS_SIZE);
+ sql = query_strip_comments->query();
+ query_length = query_strip_comments->query_length();
+ }
tot_length= query_length + thd->db_length + 1 + QUERY_CACHE_FLAGS_SIZE;
if (thd->db_length)
@@ -1587,6 +1861,8 @@
(uchar*) &flags, QUERY_CACHE_FLAGS_SIZE);
query_block = (Query_cache_block *) my_hash_search(&queries, (uchar*) sql,
tot_length);
+ sql = sql_backup;
+ query_length = query_length_backup;
/* Quick abort on unlocked data */
if (query_block == 0 ||
query_block->query()->result() == 0 ||
diff -ruN a/sql/sql_class.h b/sql/sql_class.h
--- a/sql/sql_class.h 2011-04-09 18:48:50.000000000 +0400
+++ b/sql/sql_class.h 2011-04-09 18:48:53.000000000 +0400
@@ -40,6 +40,9 @@
#include "thr_lock.h" /* thr_lock_type, THR_LOCK_DATA,
THR_LOCK_INFO */
+#ifdef HAVE_QUERY_CACHE
+#include "query_strip_comments.h"
+#endif // HAVE_QUERY_CACHE
class Reprepare_observer;
class Relay_log_info;
@@ -765,6 +768,9 @@
statement lifetime. FIXME: must be const
*/
ulong id;
+#ifdef HAVE_QUERY_CACHE
+ QueryStripComments query_strip_comments; // see sql_cache.cc
+#endif //HAVE_QUERY_CACHE
/*
MARK_COLUMNS_NONE: Means mark_used_colums is not set and no indicator to
diff -ruN a/sql/sys_vars.cc b/sql/sys_vars.cc
--- a/sql/sys_vars.cc 2011-04-09 18:48:50.000000000 +0400
+++ b/sql/sys_vars.cc 2011-04-09 18:48:53.000000000 +0400
@@ -1786,6 +1786,11 @@
NO_MUTEX_GUARD, NOT_IN_BINLOG, ON_CHECK(0),
ON_UPDATE(fix_query_cache_size));
+static Sys_var_mybool Sys_query_cache_strip_comments(
+ "query_cache_strip_comments", "Enable and disable optimisation \"strip comment for query cache\" - optimisation strip all comments from query while search query result in query cache",
+ GLOBAL_VAR(opt_query_cache_strip_comments), CMD_LINE(OPT_ARG),
+ DEFAULT(FALSE));
+
static Sys_var_ulong Sys_query_cache_limit(
"query_cache_limit",
"Don't cache results that are bigger than this",
|