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# name : optimizer_fix.patch
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# introduced : 11 or before
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# maintainer : Yasufumi
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# Any small change to this file in the main branch
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# should be done or reviewed by the maintainer!
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+++ b/patch_info/optimizer_fix.info
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+File=optimizer_fix.patch
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+Name=Unofficial optimizer fixes
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+Author=Percona <info@percona.com>
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--- a/sql/mysql_priv.h
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+++ b/sql/mysql_priv.h
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extern ulong slave_exec_mode_options;
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extern my_bool opt_readonly, lower_case_file_system;
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extern my_bool opt_userstat_running, opt_thread_statistics;
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+extern my_bool opt_optimizer_fix;
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extern my_bool opt_enable_named_pipe, opt_sync_frm, opt_allow_suspicious_udfs;
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extern my_bool opt_secure_auth;
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extern char* opt_secure_file_priv;
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#endif /* defined(ENABLED_DEBUG_SYNC) */
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my_bool opt_old_style_user_limits= 0, trust_function_creators= 0;
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my_bool opt_userstat_running= 0, opt_thread_statistics= 0;
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+my_bool opt_optimizer_fix= 0;
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True if there is at least one per-hour limit for some user, so we should
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check them before each query (and possibly reset counters when hour is
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OPT_SLOW_QUERY_LOG_FILE,
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OPT_THREAD_STATISTICS,
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OPT_USE_GLOBAL_LONG_QUERY_TIME,
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OPT_USE_GLOBAL_LOG_SLOW_CONTROL,
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OPT_SLOW_QUERY_LOG_MICROSECONDS_TIMESTAMP,
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@@ -7381,6 +7383,10 @@
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"Control TABLE_STATISTICS running, when userstat_running is enabled",
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(uchar**) &opt_thread_statistics, (uchar**) &opt_thread_statistics,
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0, GET_BOOL, NO_ARG, 0, 0, 1, 0, 1, 0},
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+ {"optimizer_fix", OPT_OPTIMIZER_FIX,
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+ "Enable unofficial optimizer fixes.",
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+ (uchar**) &opt_optimizer_fix, (uchar**) &opt_optimizer_fix,
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+ 0, GET_BOOL, NO_ARG, 1, 0, 1, 0, 1, 0},
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{"binlog-direct-non-transactional-updates", OPT_BINLOG_DIRECT_NON_TRANS_UPDATE,
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"Causes updates to non-transactional engines using statement format to be "
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"written directly to binary log. Before using this option, make sure that "
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--- a/sql/opt_range.cc
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+++ b/sql/opt_range.cc
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static TRP_RANGE *get_key_scans_params(PARAM *param, SEL_TREE *tree,
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bool index_read_must_be_used,
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bool update_tbl_stats,
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+ double read_time, ha_rows *estimated_records);
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TRP_ROR_INTERSECT *get_best_ror_intersect(const PARAM *param, SEL_TREE *tree,
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ha_rows limit, bool force_quick_range)
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+ ha_rows estimated_records=0;
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DBUG_ENTER("SQL_SELECT::test_quick_select");
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DBUG_PRINT("enter",("keys_to_use: %lu prev_tables: %lu const_tables: %lu",
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@@ -2370,12 +2371,17 @@
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/* Get best 'range' plan and prepare data for making other plans */
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if ((range_trp= get_key_scans_params(¶m, tree, FALSE, TRUE,
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+ best_read_time, &estimated_records)))
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best_read_time= best_trp->read_cost;
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+ if (opt_optimizer_fix && estimated_records)
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+ records = estimated_records;
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Simultaneous key scans and row deletes on several handler
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objects are not allowed so don't use ROR-intersection for
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DBUG_EXECUTE("info", print_sel_tree(param, *ptree, &(*ptree)->keys_map,
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"tree in SEL_IMERGE"););
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- if (!(*cur_child= get_key_scans_params(param, *ptree, TRUE, FALSE, read_time)))
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+ if (!(*cur_child= get_key_scans_params(param, *ptree, TRUE, FALSE, read_time, NULL)))
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One of index scans in this index_merge is more expensive than entire
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@@ -4829,11 +4835,12 @@
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static TRP_RANGE *get_key_scans_params(PARAM *param, SEL_TREE *tree,
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bool index_read_must_be_used,
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bool update_tbl_stats,
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+ double read_time, ha_rows *estimated_records)
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SEL_ARG **key,**end, **key_to_read= NULL;
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ha_rows UNINIT_VAR(best_records); /* protected by key_to_read */
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+ ha_rows min_records= HA_POS_ERROR;
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TRP_RANGE* read_plan= NULL;
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bool pk_is_clustered= param->table->file->primary_key_is_clustered();
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DBUG_ENTER("get_key_scans_params");
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@@ -4904,6 +4911,11 @@
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+ if (estimated_records && found_records
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+ && min_records > found_records)
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+ min_records = found_records;
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@@ -4926,6 +4938,12 @@
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DBUG_PRINT("info", ("No 'range' table read plan found"));
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+ /* minimum number of records (not 0) as estimated number of records */
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+ if (estimated_records && min_records != HA_POS_ERROR)
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+ *estimated_records = min_records;
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DBUG_RETURN(read_plan);
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&opt_userstat_running);
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static sys_var_bool_ptr sys_thread_statistics(&vars, "thread_statistics",
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&opt_thread_statistics);
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+static sys_var_bool_ptr sys_optimizer_fix(&vars, "optimizer_fix",
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+ &opt_optimizer_fix);
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static sys_var_thd_ulong sys_read_rnd_buff_size(&vars, "read_rnd_buffer_size",
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&SV::read_rnd_buff_size);
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static sys_var_thd_ulong sys_div_precincrement(&vars, "div_precision_increment",
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--- a/sql/sql_select.cc
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+++ b/sql/sql_select.cc
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@@ -2605,6 +2605,11 @@
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table->reginfo.impossible_range=1;
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+ if (opt_optimizer_fix && error == 0)
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+ /* quick select is not effective. but the estimated value is used. */
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+ DBUG_RETURN(select->records);
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DBUG_PRINT("warning",("Couldn't use record count on const keypart"));
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DBUG_RETURN(HA_POS_ERROR); /* This shouldn't happend */
added
removed
patches/optimizer_fix.patch
