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MDEV-39251: Add an option to count records_in_range calls and skip them for point lookups
Add @@optimizer_min_point_range_size_to_use_stats. If the range optimizer estimates a point lookup and the index statistics say that expected number of matching rows is less than that, then skip records_in_range() and use index statistics. The default is @@optimizer_min_point_range_size_to_use_stats=0 which means the old behavior (use records_in_range(), unless the lookup is over unique key, or @@eq_range_index_dive_limit is hit)
1 parent a13fbcf commit 78ccd80

9 files changed

Lines changed: 276 additions & 3 deletions

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‎mysql-test/main/mysqld--help.result‎

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@@ -849,6 +849,9 @@ The following specify which files/extra groups are read (specified before remain
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The maximum number of SEL_ARG objects created when
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optimizing a range. If more objects would be needed, the
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range will not be used by the optimizer
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--optimizer-min-point-range-size-to-use-stats=#
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Minimum point range size for which the optimizer will use
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statistics instead of records_in_range call
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--optimizer-prune-level=#
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Controls the heuristic(s) applied during query
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optimization to prune less-promising partial plans from
@@ -1883,6 +1886,7 @@ optimizer-key-lookup-cost 0.435777
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optimizer-key-next-find-cost 0.082347
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optimizer-max-sel-arg-weight 32000
18851888
optimizer-max-sel-args 16000
1889+
optimizer-min-point-range-size-to-use-stats 0
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optimizer-prune-level 2
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optimizer-row-copy-cost 0.060866
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optimizer-row-lookup-cost 0.130839

‎mysql-test/main/range.result‎

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@@ -3871,5 +3871,91 @@ l_orderkey
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291
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DROP TABLE lineitem;
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#
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# MDEV-39251: Add an option to count records_in_range calls and skip them for point lookups
3875+
#
3876+
create table t1 (
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a int,
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b int,
3879+
index(a),
3880+
index(b)
3881+
);
3882+
insert into t1 select seq, floor(seq/10) from seq_1_to_100;
3883+
#
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# The default behavior is to make records_in_range calls:
3885+
#
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flush status;
3887+
explain select * from t1 where a in (1,2);
3888+
id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 range a a 5 NULL 2 Using index condition
3890+
show status like 'Handler_records_in_range';
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Variable_name Value
3892+
Handler_records_in_range 2
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flush status;
3894+
explain select * from t1 where a=1;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ref a a 5 const 1
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show status like 'Handler_records_in_range';
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Variable_name Value
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Handler_records_in_range 1
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flush status;
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explain select * from t1 where b=1;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ref b b 5 const 5
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show status like 'Handler_records_in_range';
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Variable_name Value
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Handler_records_in_range 1
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#
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# Now, INDEX(a) should be handled without records_in_range:
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#
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set @tmp=@@optimizer_min_point_range_size_to_use_stats;
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set optimizer_min_point_range_size_to_use_stats=5;
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flush status;
3913+
explain select * from t1 where a in (1,2);
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 range a a 5 NULL 2 Using index condition
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show status like 'Handler_records_in_range';
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Variable_name Value
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Handler_records_in_range 0
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flush status;
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explain select * from t1 where a=1;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ref a a 5 const 1
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show status like 'Handler_records_in_range';
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Variable_name Value
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Handler_records_in_range 0
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flush status;
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explain select * from t1 where b=1;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ref b b 5 const 5
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show status like 'Handler_records_in_range';
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Variable_name Value
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Handler_records_in_range 1
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#
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# Now, both INDEX(a) and INDEX(a) should be handled without records_in_range:
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#
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set optimizer_min_point_range_size_to_use_stats=30;
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flush status;
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explain select * from t1 where a in (1,2);
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 range a a 5 NULL 2 Using index condition
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show status like 'Handler_records_in_range';
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Variable_name Value
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Handler_records_in_range 0
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flush status;
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explain select * from t1 where a=1;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ref a a 5 const 1
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show status like 'Handler_records_in_range';
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Variable_name Value
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Handler_records_in_range 0
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flush status;
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explain select * from t1 where b=1;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ref b b 5 const 9
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show status like 'Handler_records_in_range';
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Variable_name Value
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Handler_records_in_range 0
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set optimizer_min_point_range_size_to_use_stats=@tmp;
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#
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# End of 11.0 tests
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#

‎mysql-test/main/range.test‎

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@@ -2638,6 +2638,69 @@ EXPLAIN SELECT DISTINCT l_orderkey FROM lineitem FORCE KEY (i_l_orderkey, i_l_re
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SELECT DISTINCT l_orderkey FROM lineitem FORCE KEY (i_l_orderkey, i_l_receiptdate) WHERE l_orderkey > 1 ORDER BY l_receiptdate;
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DROP TABLE lineitem;
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--echo #
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--echo # MDEV-39251: Add an option to count records_in_range calls and skip them for point lookups
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--echo #
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create table t1 (
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a int,
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b int,
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index(a),
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index(b)
2649+
);
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insert into t1 select seq, floor(seq/10) from seq_1_to_100;
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--echo #
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--echo # The default behavior is to make records_in_range calls:
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--echo #
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flush status;
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explain select * from t1 where a in (1,2);
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show status like 'Handler_records_in_range';
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flush status;
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explain select * from t1 where a=1;
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show status like 'Handler_records_in_range';
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flush status;
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explain select * from t1 where b=1;
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show status like 'Handler_records_in_range';
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--echo #
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--echo # Now, INDEX(a) should be handled without records_in_range:
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--echo #
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set @tmp=@@optimizer_min_point_range_size_to_use_stats;
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set optimizer_min_point_range_size_to_use_stats=5;
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flush status;
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explain select * from t1 where a in (1,2);
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show status like 'Handler_records_in_range';
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flush status;
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explain select * from t1 where a=1;
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show status like 'Handler_records_in_range';
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flush status;
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explain select * from t1 where b=1;
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show status like 'Handler_records_in_range';
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--echo #
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--echo # Now, both INDEX(a) and INDEX(a) should be handled without records_in_range:
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--echo #
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set optimizer_min_point_range_size_to_use_stats=30;
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flush status;
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explain select * from t1 where a in (1,2);
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show status like 'Handler_records_in_range';
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flush status;
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explain select * from t1 where a=1;
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show status like 'Handler_records_in_range';
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flush status;
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explain select * from t1 where b=1;
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show status like 'Handler_records_in_range';
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set optimizer_min_point_range_size_to_use_stats=@tmp;
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--echo #
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--echo # End of 11.0 tests
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--echo #

‎mysql-test/main/range_mrr_icp.result‎

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@@ -3869,6 +3869,92 @@ l_orderkey
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291
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DROP TABLE lineitem;
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#
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# MDEV-39251: Add an option to count records_in_range calls and skip them for point lookups
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#
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create table t1 (
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a int,
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b int,
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index(a),
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index(b)
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);
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insert into t1 select seq, floor(seq/10) from seq_1_to_100;
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#
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# The default behavior is to make records_in_range calls:
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#
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flush status;
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explain select * from t1 where a in (1,2);
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 range a a 5 NULL 2 Using index condition; Rowid-ordered scan
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show status like 'Handler_records_in_range';
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Variable_name Value
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Handler_records_in_range 2
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flush status;
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explain select * from t1 where a=1;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ref a a 5 const 1
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show status like 'Handler_records_in_range';
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Variable_name Value
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Handler_records_in_range 1
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flush status;
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explain select * from t1 where b=1;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ref b b 5 const 5
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show status like 'Handler_records_in_range';
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Variable_name Value
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Handler_records_in_range 1
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#
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# Now, INDEX(a) should be handled without records_in_range:
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#
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set @tmp=@@optimizer_min_point_range_size_to_use_stats;
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set optimizer_min_point_range_size_to_use_stats=5;
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flush status;
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explain select * from t1 where a in (1,2);
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 range a a 5 NULL 2 Using index condition; Rowid-ordered scan
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show status like 'Handler_records_in_range';
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Variable_name Value
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Handler_records_in_range 0
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flush status;
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explain select * from t1 where a=1;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ref a a 5 const 1
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show status like 'Handler_records_in_range';
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Variable_name Value
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Handler_records_in_range 0
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flush status;
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explain select * from t1 where b=1;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ref b b 5 const 5
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show status like 'Handler_records_in_range';
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Variable_name Value
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Handler_records_in_range 1
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#
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# Now, both INDEX(a) and INDEX(a) should be handled without records_in_range:
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#
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set optimizer_min_point_range_size_to_use_stats=30;
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flush status;
3936+
explain select * from t1 where a in (1,2);
3937+
id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 range a a 5 NULL 2 Using index condition; Rowid-ordered scan
3939+
show status like 'Handler_records_in_range';
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Variable_name Value
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Handler_records_in_range 0
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flush status;
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explain select * from t1 where a=1;
3944+
id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ref a a 5 const 1
3946+
show status like 'Handler_records_in_range';
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Variable_name Value
3948+
Handler_records_in_range 0
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flush status;
3950+
explain select * from t1 where b=1;
3951+
id select_type table type possible_keys key key_len ref rows Extra
3952+
1 SIMPLE t1 ref b b 5 const 9
3953+
show status like 'Handler_records_in_range';
3954+
Variable_name Value
3955+
Handler_records_in_range 0
3956+
set optimizer_min_point_range_size_to_use_stats=@tmp;
3957+
#
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# End of 11.0 tests
38733959
#
38743960
set optimizer_switch=@mrr_icp_extra_tmp;

‎mysql-test/suite/sys_vars/r/sysvars_server_embedded.result‎

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@@ -2572,6 +2572,16 @@ NUMERIC_BLOCK_SIZE 1
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ENUM_VALUE_LIST NULL
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READ_ONLY NO
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COMMAND_LINE_ARGUMENT REQUIRED
2575+
VARIABLE_NAME OPTIMIZER_MIN_POINT_RANGE_SIZE_TO_USE_STATS
2576+
VARIABLE_SCOPE SESSION
2577+
VARIABLE_TYPE BIGINT UNSIGNED
2578+
VARIABLE_COMMENT Minimum point range size for which the optimizer will use statistics instead of records_in_range call
2579+
NUMERIC_MIN_VALUE 0
2580+
NUMERIC_MAX_VALUE 18446744073709551615
2581+
NUMERIC_BLOCK_SIZE 1
2582+
ENUM_VALUE_LIST NULL
2583+
READ_ONLY NO
2584+
COMMAND_LINE_ARGUMENT REQUIRED
25752585
VARIABLE_NAME OPTIMIZER_PRUNE_LEVEL
25762586
VARIABLE_SCOPE SESSION
25772587
VARIABLE_TYPE BIGINT UNSIGNED

‎mysql-test/suite/sys_vars/r/sysvars_server_notembedded.result‎

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@@ -2782,6 +2782,16 @@ NUMERIC_BLOCK_SIZE 1
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ENUM_VALUE_LIST NULL
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READ_ONLY NO
27842784
COMMAND_LINE_ARGUMENT REQUIRED
2785+
VARIABLE_NAME OPTIMIZER_MIN_POINT_RANGE_SIZE_TO_USE_STATS
2786+
VARIABLE_SCOPE SESSION
2787+
VARIABLE_TYPE BIGINT UNSIGNED
2788+
VARIABLE_COMMENT Minimum point range size for which the optimizer will use statistics instead of records_in_range call
2789+
NUMERIC_MIN_VALUE 0
2790+
NUMERIC_MAX_VALUE 18446744073709551615
2791+
NUMERIC_BLOCK_SIZE 1
2792+
ENUM_VALUE_LIST NULL
2793+
READ_ONLY NO
2794+
COMMAND_LINE_ARGUMENT REQUIRED
27852795
VARIABLE_NAME OPTIMIZER_PRUNE_LEVEL
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VARIABLE_SCOPE SESSION
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VARIABLE_TYPE BIGINT UNSIGNED

‎sql/multi_range_read.cc‎

Lines changed: 6 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -240,10 +240,13 @@ handler::multi_range_read_info_const(uint keyno, RANGE_SEQ_IF *seq,
240240
*/
241241
single_point_ranges++;
242242
}
243-
else if (use_statistics_for_eq_range &&
244-
!(range.range_flag & NULL_RANGE) &&
243+
else if (!(range.range_flag & NULL_RANGE) &&
245244
(range.range_flag & EQ_RANGE) &&
246-
table->key_info[keyno].actual_rec_per_key(keyparts_used - 1) > 0.5)
245+
(use_statistics_for_eq_range ||
246+
(thd->variables.optimizer_min_point_range_size_to_use_stats >
247+
table->key_info[keyno].actual_rec_per_key(keyparts_used - 1))
248+
) &&
249+
table->key_info[keyno].actual_rec_per_key(keyparts_used - 1) > 0.5 )
247250
{
248251
rows= ((ha_rows) table->key_info[keyno].
249252
actual_rec_per_key(keyparts_used-1));

‎sql/sql_class.h‎

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -775,6 +775,7 @@ typedef struct system_variables
775775
ha_rows select_limit;
776776
ha_rows max_join_size;
777777
ha_rows expensive_subquery_limit;
778+
ha_rows optimizer_min_point_range_size_to_use_stats;
778779

779780
#ifdef WITH_WSREP
780781
/*

‎sql/sys_vars.cc‎

Lines changed: 10 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -3102,6 +3102,16 @@ static Sys_var_ulong Sys_optimizer_adjust_secondary_key_costs(
31023102
NO_MUTEX_GUARD, NOT_IN_BINLOG, ON_CHECK(0), ON_UPDATE(0),
31033103
DEPRECATED(1100, ""));
31043104

3105+
static Sys_var_harows Sys_optimizer_min_point_range_size_to_use_stats(
3106+
"optimizer_min_point_range_size_to_use_stats",
3107+
"Minimum point range size for which the optimizer will use "
3108+
"statistics instead of records_in_range call",
3109+
SESSION_VAR(optimizer_min_point_range_size_to_use_stats),
3110+
CMD_LINE(REQUIRED_ARG),
3111+
VALID_RANGE(0, HA_POS_ERROR), DEFAULT(0), BLOCK_SIZE(1),
3112+
NO_MUTEX_GUARD, NOT_IN_BINLOG, ON_CHECK(0),
3113+
ON_UPDATE(0));
3114+
31053115
static Sys_var_charptr_fscs Sys_pid_file(
31063116
"pid_file", "Pid file used by mariadbd-safe",
31073117
READ_ONLY GLOBAL_VAR(pidfile_name_ptr), CMD_LINE(REQUIRED_ARG),

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