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# name : optimizer_fix.patch
# introduced : 11 or before
# maintainer : Yasufumi
#
#!!! 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/optimizer_fix.info
--- /dev/null 1970-01-01 09:00:00.000000000 +0900
+++ b/patch_info/optimizer_fix.info 2010-07-26 18:29:35.685061376 +0900
@@ -0,0 +1,8 @@
+File=optimizer_fix.patch
+Name=Unofficial optimizer fixes
+Version=1.0
+Author=Percona <info@percona.com>
+License=GPL
+Comment=
+2010-01
+Ported to 5.1.42
diff -ruN a/sql/mysql_priv.h b/sql/mysql_priv.h
--- a/sql/mysql_priv.h 2010-07-26 18:29:12.224113574 +0900
+++ b/sql/mysql_priv.h 2010-07-26 18:29:35.697144981 +0900
@@ -2110,6 +2110,7 @@
extern ulong slave_exec_mode_options;
extern my_bool opt_readonly, lower_case_file_system;
extern my_bool opt_userstat_running, opt_thread_statistics;
+extern my_bool opt_optimizer_fix;
extern my_bool opt_enable_named_pipe, opt_sync_frm, opt_allow_suspicious_udfs;
extern my_bool opt_secure_auth;
extern char* opt_secure_file_priv;
diff -ruN a/sql/mysqld.cc b/sql/mysqld.cc
--- a/sql/mysqld.cc 2010-07-26 18:29:12.238109757 +0900
+++ b/sql/mysqld.cc 2010-07-26 18:29:35.687113582 +0900
@@ -533,6 +533,7 @@
#endif /* defined(ENABLED_DEBUG_SYNC) */
my_bool opt_old_style_user_limits= 0, trust_function_creators= 0;
my_bool opt_userstat_running= 0, opt_thread_statistics= 0;
+my_bool opt_optimizer_fix= 0;
/*
True if there is at least one per-hour limit for some user, so we should
check them before each query (and possibly reset counters when hour is
@@ -5849,6 +5850,7 @@
OPT_SLOW_QUERY_LOG_FILE,
OPT_USERSTAT_RUNNING,
OPT_THREAD_STATISTICS,
+ OPT_OPTIMIZER_FIX,
OPT_USE_GLOBAL_LONG_QUERY_TIME,
OPT_USE_GLOBAL_LOG_SLOW_CONTROL,
OPT_SLOW_QUERY_LOG_MICROSECONDS_TIMESTAMP,
@@ -7358,6 +7360,10 @@
"Control TABLE_STATISTICS running, when userstat_running is enabled",
(uchar**) &opt_thread_statistics, (uchar**) &opt_thread_statistics,
0, GET_BOOL, NO_ARG, 0, 0, 1, 0, 1, 0},
+ {"optimizer_fix", OPT_OPTIMIZER_FIX,
+ "Enable unofficial optimizer fixes.",
+ (uchar**) &opt_optimizer_fix, (uchar**) &opt_optimizer_fix,
+ 0, GET_BOOL, NO_ARG, 1, 0, 1, 0, 1, 0},
{"binlog-direct-non-transactional-updates", OPT_BINLOG_DIRECT_NON_TRANS_UPDATE,
"Causes updates to non-transactional engines using statement format to be "
"written directly to binary log. Before using this option, make sure that "
diff -ruN a/sql/opt_range.cc b/sql/opt_range.cc
--- a/sql/opt_range.cc 2010-07-09 21:34:57.000000000 +0900
+++ b/sql/opt_range.cc 2010-07-26 18:29:35.711113511 +0900
@@ -695,7 +695,7 @@
static TRP_RANGE *get_key_scans_params(PARAM *param, SEL_TREE *tree,
bool index_read_must_be_used,
bool update_tbl_stats,
- double read_time);
+ double read_time, ha_rows *estimated_records);
static
TRP_ROR_INTERSECT *get_best_ror_intersect(const PARAM *param, SEL_TREE *tree,
double read_time,
@@ -2200,6 +2200,7 @@
ha_rows limit, bool force_quick_range)
{
uint idx;
+ ha_rows estimated_records=0;
double scan_time;
DBUG_ENTER("SQL_SELECT::test_quick_select");
DBUG_PRINT("enter",("keys_to_use: %lu prev_tables: %lu const_tables: %lu",
@@ -2370,12 +2371,17 @@
/* Get best 'range' plan and prepare data for making other plans */
if ((range_trp= get_key_scans_params(¶m, tree, FALSE, TRUE,
- best_read_time)))
+ best_read_time, &estimated_records)))
{
best_trp= range_trp;
best_read_time= best_trp->read_cost;
}
+ if (opt_optimizer_fix && estimated_records)
+ {
+ records = estimated_records;
+ }
+
/*
Simultaneous key scans and row deletes on several handler
objects are not allowed so don't use ROR-intersection for
@@ -3726,7 +3732,7 @@
{
DBUG_EXECUTE("info", print_sel_tree(param, *ptree, &(*ptree)->keys_map,
"tree in SEL_IMERGE"););
- if (!(*cur_child= get_key_scans_params(param, *ptree, TRUE, FALSE, read_time)))
+ if (!(*cur_child= get_key_scans_params(param, *ptree, TRUE, FALSE, read_time, NULL)))
{
/*
One of index scans in this index_merge is more expensive than entire
@@ -4829,11 +4835,12 @@
static TRP_RANGE *get_key_scans_params(PARAM *param, SEL_TREE *tree,
bool index_read_must_be_used,
bool update_tbl_stats,
- double read_time)
+ double read_time, ha_rows *estimated_records)
{
int idx;
SEL_ARG **key,**end, **key_to_read= NULL;
ha_rows UNINIT_VAR(best_records); /* protected by key_to_read */
+ ha_rows min_records= HA_POS_ERROR;
TRP_RANGE* read_plan= NULL;
bool pk_is_clustered= param->table->file->primary_key_is_clustered();
DBUG_ENTER("get_key_scans_params");
@@ -4904,6 +4911,11 @@
key_to_read= key;
}
+ if (estimated_records && found_records
+ && min_records > found_records)
+ {
+ min_records = found_records;
+ }
}
}
@@ -4926,6 +4938,12 @@
else
DBUG_PRINT("info", ("No 'range' table read plan found"));
+ /* minimum number of records (not 0) as estimated number of records */
+ if (estimated_records && min_records != HA_POS_ERROR)
+ {
+ *estimated_records = min_records;
+ }
+
DBUG_RETURN(read_plan);
}
diff -ruN a/sql/set_var.cc b/sql/set_var.cc
--- a/sql/set_var.cc 2010-07-26 18:29:12.250113584 +0900
+++ b/sql/set_var.cc 2010-07-26 18:29:35.724113196 +0900
@@ -571,6 +571,8 @@
&opt_userstat_running);
static sys_var_bool_ptr sys_thread_statistics(&vars, "thread_statistics",
&opt_thread_statistics);
+static sys_var_bool_ptr sys_optimizer_fix(&vars, "optimizer_fix",
+ &opt_optimizer_fix);
static sys_var_thd_ulong sys_read_rnd_buff_size(&vars, "read_rnd_buffer_size",
&SV::read_rnd_buff_size);
static sys_var_thd_ulong sys_div_precincrement(&vars, "div_precision_increment",
diff -ruN a/sql/sql_select.cc b/sql/sql_select.cc
--- a/sql/sql_select.cc 2010-07-26 18:23:40.015145156 +0900
+++ b/sql/sql_select.cc 2010-07-26 18:29:35.743144611 +0900
@@ -2601,6 +2601,11 @@
table->reginfo.impossible_range=1;
DBUG_RETURN(0);
}
+ if (opt_optimizer_fix && error == 0)
+ {
+ /* quick select is not effective. but the estimated value is used. */
+ DBUG_RETURN(select->records);
+ }
DBUG_PRINT("warning",("Couldn't use record count on const keypart"));
}
DBUG_RETURN(HA_POS_ERROR); /* This shouldn't happend */
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