revision-id: a0643458ca5bcd69e91cffcb9e637f544aca7cf1 (mariadb-10.6.1-231-ga0643458ca5)
parent(s): d3b5ea4c6b0d3abbe18bf63d9fe076dcb0a043ce
author: Sergei Petrunia
committer: Sergei Petrunia
timestamp: 2021-12-14 01:47:01 +0300
message:
MDEV-26996: Support descending indexes in the range optimizer
Make the Range Optimizer support descending index key parts.
We follow the approach taken in MySQL-8.
See HowRangeOptimizerHandlesDescKeyparts for the description.
---
mysql-test/main/desc_index_range.result | 158 ++++++++++++++++++++++
mysql-test/main/desc_index_range.test | 74 +++++++++++
sql/item_geofunc.cc | 3 +-
sql/key.cc | 16 ++-
sql/opt_range.cc | 162 +++++++++++++++-------
sql/opt_range.h | 229 ++++++++++++++++++++++++++++----
sql/opt_range_mrr.cc | 46 +++----
7 files changed, 583 insertions(+), 105 deletions(-)
diff --git a/mysql-test/main/desc_index_range.result b/mysql-test/main/desc_index_range.result
new file mode 100644
index 00000000000..53a608fe2d9
--- /dev/null
+++ b/mysql-test/main/desc_index_range.result
@@ -0,0 +1,158 @@
+create table t1 (
+a int,
+key (a desc)
+);
+insert into t1 select seq from seq_1_to_1000;
+set optimizer_trace=1;
+explain select * from t1 force index(a) where a in (2, 4, 6);
+id select_type table type possible_keys key key_len ref rows Extra
+1 SIMPLE t1 range a a 5 NULL 3 Using where; Using index
+select json_detailed(json_extract(trace, '$**.range_access_plan.ranges'))
+from information_schema.optimizer_trace;
+json_detailed(json_extract(trace, '$**.range_access_plan.ranges'))
+[
+
+ [
+ "(6) <= (a) <= (6)",
+ "(4) <= (a) <= (4)",
+ "(2) <= (a) <= (2)"
+ ]
+]
+set optimizer_trace=default;
+# These should go in reverse order:
+select * from t1 force index(a) where a in (2, 4, 6);
+a
+6
+4
+2
+drop table t1;
+#
+# Multi-part key tests
+#
+create table t1 (
+a int not null,
+b int not null,
+key ab(a, b desc)
+);
+insert into t1 select A.seq, B.seq*10 from seq_1_to_10 A, seq_1_to_10 B;
+set optimizer_trace=1;
+explain select * from t1 force index(ab) where a>=8 and b>=50;
+id select_type table type possible_keys key key_len ref rows Extra
+1 SIMPLE t1 range ab ab 4 NULL 51 Using where; Using index
+select json_detailed(json_extract(trace, '$**.range_access_plan.ranges'))
+from information_schema.optimizer_trace;
+json_detailed(json_extract(trace, '$**.range_access_plan.ranges'))
+[
+
+ [
+ "(8) <= (a)"
+ ]
+]
+explain select * from t1 force index(ab) where a>=8 and b<=50;
+id select_type table type possible_keys key key_len ref rows Extra
+1 SIMPLE t1 range ab ab 8 NULL 46 Using where; Using index
+select json_detailed(json_extract(trace, '$**.range_access_plan.ranges'))
+from information_schema.optimizer_trace;
+json_detailed(json_extract(trace, '$**.range_access_plan.ranges'))
+[
+
+ [
+ "(8,50) <= (a,b)"
+ ]
+]
+select * from t1 force index(ab) where a>=8 and b<=50;
+a b
+8 50
+8 40
+8 30
+8 20
+8 10
+9 50
+9 40
+9 30
+9 20
+9 10
+10 50
+10 40
+10 30
+10 20
+10 10
+select * from t1 ignore index(ab) where a>=8 and b<=50 order by a, b desc;
+a b
+8 50
+8 40
+8 30
+8 20
+8 10
+9 50
+9 40
+9 30
+9 20
+9 10
+10 50
+10 40
+10 30
+10 20
+10 10
+explain
+select * from t1 where a between 2 and 4 and b between 50 and 80;
+id select_type table type possible_keys key key_len ref rows Extra
+1 SIMPLE t1 range ab ab 8 NULL 17 Using where; Using index
+select json_detailed(json_extract(trace, '$**.range_access_plan.ranges'))
+from information_schema.optimizer_trace;
+json_detailed(json_extract(trace, '$**.range_access_plan.ranges'))
+[
+
+ [
+ "(2,80) <= (a,b) <= (4,50)"
+ ]
+]
+select * from t1 where a between 2 and 4 and b between 50 and 80;
+a b
+2 80
+2 70
+2 60
+2 50
+3 80
+3 70
+3 60
+3 50
+4 80
+4 70
+4 60
+4 50
+drop table t1;
+create table t2 (
+a int not null,
+b int not null,
+key ab(a desc, b desc)
+);
+insert into t2 select A.seq, B.seq*10 from seq_1_to_10 A, seq_1_to_10 B;
+explain
+select * from t2 where a between 2 and 4;
+id select_type table type possible_keys key key_len ref rows Extra
+1 SIMPLE t2 range ab ab 4 NULL 40 Using where; Using index
+select json_detailed(json_extract(trace, '$**.range_access_plan.ranges'))
+from information_schema.optimizer_trace;
+json_detailed(json_extract(trace, '$**.range_access_plan.ranges'))
+[
+
+ [
+ "(4) <= (a) <= (2)"
+ ]
+]
+explain
+select * from t2 where a between 2 and 4 and b between 50 and 80;
+id select_type table type possible_keys key key_len ref rows Extra
+1 SIMPLE t2 range ab ab 8 NULL 31 Using where; Using index
+select json_detailed(json_extract(trace, '$**.range_access_plan.ranges'))
+from information_schema.optimizer_trace;
+json_detailed(json_extract(trace, '$**.range_access_plan.ranges'))
+[
+
+ [
+ "(4,80) <= (a,b) <= (2,50)"
+ ]
+]
+set optimizer_trace=default;
+drop table t2;
diff --git a/mysql-test/main/desc_index_range.test b/mysql-test/main/desc_index_range.test
new file mode 100644
index 00000000000..7fdf439c523
--- /dev/null
+++ b/mysql-test/main/desc_index_range.test
@@ -0,0 +1,74 @@
+#
+# Tests for range access and descending indexes
+#
+--source include/have_sequence.inc
+--source include/have_innodb.inc
+
+create table t1 (
+ a int,
+ key (a desc)
+);
+insert into t1 select seq from seq_1_to_1000;
+
+set optimizer_trace=1;
+explain select * from t1 force index(a) where a in (2, 4, 6);
+
+select json_detailed(json_extract(trace, '$**.range_access_plan.ranges'))
+from information_schema.optimizer_trace;
+set optimizer_trace=default;
+
+--echo # These should go in reverse order:
+select * from t1 force index(a) where a in (2, 4, 6);
+drop table t1;
+
+--echo #
+--echo # Multi-part key tests
+--echo #
+create table t1 (
+ a int not null,
+ b int not null,
+ key ab(a, b desc)
+);
+
+insert into t1 select A.seq, B.seq*10 from seq_1_to_10 A, seq_1_to_10 B;
+
+set optimizer_trace=1;
+explain select * from t1 force index(ab) where a>=8 and b>=50;
+select json_detailed(json_extract(trace, '$**.range_access_plan.ranges'))
+from information_schema.optimizer_trace;
+
+explain select * from t1 force index(ab) where a>=8 and b<=50;
+select json_detailed(json_extract(trace, '$**.range_access_plan.ranges'))
+from information_schema.optimizer_trace;
+
+select * from t1 force index(ab) where a>=8 and b<=50;
+select * from t1 ignore index(ab) where a>=8 and b<=50 order by a, b desc;
+
+explain
+select * from t1 where a between 2 and 4 and b between 50 and 80;
+select json_detailed(json_extract(trace, '$**.range_access_plan.ranges'))
+from information_schema.optimizer_trace;
+
+select * from t1 where a between 2 and 4 and b between 50 and 80;
+
+drop table t1;
+
+create table t2 (
+ a int not null,
+ b int not null,
+ key ab(a desc, b desc)
+);
+insert into t2 select A.seq, B.seq*10 from seq_1_to_10 A, seq_1_to_10 B;
+
+explain
+select * from t2 where a between 2 and 4;
+select json_detailed(json_extract(trace, '$**.range_access_plan.ranges'))
+from information_schema.optimizer_trace;
+
+explain
+select * from t2 where a between 2 and 4 and b between 50 and 80;
+select json_detailed(json_extract(trace, '$**.range_access_plan.ranges'))
+from information_schema.optimizer_trace;
+
+set optimizer_trace=default;
+drop table t2;
diff --git a/sql/item_geofunc.cc b/sql/item_geofunc.cc
index 49b85e2213b..a2a99bcdf8f 100644
--- a/sql/item_geofunc.cc
+++ b/sql/item_geofunc.cc
@@ -1083,7 +1083,8 @@ Item_func_spatial_rel::get_mm_leaf(RANGE_OPT_PARAM *param,
DBUG_RETURN(0); // out of memory
field->get_key_image(str, key_part->length, key_part->image_type);
SEL_ARG *tree;
- if (!(tree= new (param->mem_root) SEL_ARG(field, str, str)))
+
+ if (!(tree= new (param->mem_root) SEL_ARG(field, true, str, str)))
DBUG_RETURN(0); // out of memory
switch (type) {
diff --git a/sql/key.cc b/sql/key.cc
index f2cebfe6d82..c43d3c36d5d 100644
--- a/sql/key.cc
+++ b/sql/key.cc
@@ -495,6 +495,7 @@ int key_cmp(KEY_PART_INFO *key_part, const uchar *key, uint key_length)
{
int cmp;
store_length= key_part->store_length;
+ int sort_order = (key_part->key_part_flag & HA_REVERSE_SORT) ? -1 : 1;
if (key_part->null_bit)
{
/* This key part allows null values; NULL is lower than everything */
@@ -503,19 +504,19 @@ int key_cmp(KEY_PART_INFO *key_part, const uchar *key, uint key_length)
{
/* the range is expecting a null value */
if (!field_is_null)
- return 1; // Found key is > range
+ return sort_order; // Found key is > range
/* null -- exact match, go to next key part */
continue;
}
else if (field_is_null)
- return -1; // NULL is less than any value
+ return -sort_order; // NULL is less than any value
key++; // Skip null byte
store_length--;
}
if ((cmp=key_part->field->key_cmp(key, key_part->length)) < 0)
- return -1;
+ return -sort_order;
if (cmp > 0)
- return 1;
+ return sort_order;
}
return 0; // Keys are equal
}
@@ -574,6 +575,7 @@ int key_rec_cmp(void *key_p, uchar *first_rec, uchar *second_rec)
do
{
field= key_part->field;
+ int sort_order = (key_part->key_part_flag & HA_REVERSE_SORT) ? -1 : 1;
if (key_part->null_bit)
{
@@ -593,12 +595,12 @@ int key_rec_cmp(void *key_p, uchar *first_rec, uchar *second_rec)
; /* Fall through, no NULL fields */
else
{
- DBUG_RETURN(+1);
+ DBUG_RETURN(sort_order);
}
}
else if (!sec_is_null)
{
- DBUG_RETURN(-1);
+ DBUG_RETURN(-sort_order);
}
else
goto next_loop; /* Both were NULL */
@@ -612,7 +614,7 @@ int key_rec_cmp(void *key_p, uchar *first_rec, uchar *second_rec)
*/
if ((result= field->cmp_prefix(field->ptr+first_diff, field->ptr+sec_diff,
key_part->length)))
- DBUG_RETURN(result);
+ DBUG_RETURN(result * sort_order);
next_loop:
key_part++;
key_part_num++;
diff --git a/sql/opt_range.cc b/sql/opt_range.cc
index 86539046a32..541a921435a 100644
--- a/sql/opt_range.cc
+++ b/sql/opt_range.cc
@@ -1879,6 +1879,7 @@ SEL_ARG::SEL_ARG(SEL_ARG &arg) :Sql_alloc()
max_flag=arg.max_flag;
maybe_flag=arg.maybe_flag;
maybe_null=arg.maybe_null;
+ is_ascending= arg.is_ascending;
part=arg.part;
field=arg.field;
min_value=arg.min_value;
@@ -1904,9 +1905,10 @@ inline void SEL_ARG::make_root()
use_count=0; elements=1;
}
-SEL_ARG::SEL_ARG(Field *f,const uchar *min_value_arg,
+SEL_ARG::SEL_ARG(Field *f, bool is_asc, const uchar *min_value_arg,
const uchar *max_value_arg)
:min_flag(0), max_flag(0), maybe_flag(0), maybe_null(f->real_maybe_null()),
+ is_ascending(is_asc),
elements(1), use_count(1), field(f), min_value((uchar*) min_value_arg),
max_value((uchar*) max_value_arg), next(0),prev(0),
next_key_part(0), color(BLACK), type(KEY_RANGE), weight(1)
@@ -1915,11 +1917,12 @@ SEL_ARG::SEL_ARG(Field *f,const uchar *min_value_arg,
max_part_no= 1;
}
-SEL_ARG::SEL_ARG(Field *field_,uint8 part_,
+SEL_ARG::SEL_ARG(Field *field_,uint8 part_, bool is_asc_,
uchar *min_value_, uchar *max_value_,
uint8 min_flag_,uint8 max_flag_,uint8 maybe_flag_)
:min_flag(min_flag_),max_flag(max_flag_),maybe_flag(maybe_flag_),
- part(part_),maybe_null(field_->real_maybe_null()), elements(1),use_count(1),
+ part(part_),maybe_null(field_->real_maybe_null()), is_ascending(is_asc_),
+ elements(1),use_count(1),
field(field_), min_value(min_value_), max_value(max_value_),
next(0),prev(0),next_key_part(0),color(BLACK),type(KEY_RANGE), weight(1)
{
@@ -1938,8 +1941,8 @@ SEL_ARG::SEL_ARG(Field *field_,uint8 part_,
class SEL_ARG_LE: public SEL_ARG
{
public:
- SEL_ARG_LE(const uchar *key, Field *field)
- :SEL_ARG(field, key, key)
+ SEL_ARG_LE(const uchar *key, Field *field, bool is_asc)
+ :SEL_ARG(field, is_asc, key, key)
{
if (!field->real_maybe_null())
min_flag= NO_MIN_RANGE; // From start
@@ -1959,16 +1962,17 @@ class SEL_ARG_LT: public SEL_ARG_LE
Use this constructor if value->save_in_field() went precisely,
without any data rounding or truncation.
*/
- SEL_ARG_LT(const uchar *key, Field *field)
- :SEL_ARG_LE(key, field)
+ SEL_ARG_LT(const uchar *key, Field *field, bool is_asc)
+ :SEL_ARG_LE(key, field, is_asc)
{ max_flag= NEAR_MAX; }
/*
Use this constructor if value->save_in_field() returned success,
but we don't know if rounding or truncation happened
(as some Field::store() do not report minor data changes).
*/
- SEL_ARG_LT(THD *thd, const uchar *key, Field *field, Item *value)
- :SEL_ARG_LE(key, field)
+ SEL_ARG_LT(THD *thd, const uchar *key, Field *field, bool is_asc,
+ Item *value)
+ :SEL_ARG_LE(key, field, is_asc)
{
if (stored_field_cmp_to_item(thd, field, value) == 0)
max_flag= NEAR_MAX;
@@ -1984,7 +1988,7 @@ class SEL_ARG_GT: public SEL_ARG
without any data rounding or truncation.
*/
SEL_ARG_GT(const uchar *key, const KEY_PART *key_part, Field *field)
- :SEL_ARG(field, key, key)
+ :SEL_ARG(field, !(key_part->flag & HA_REVERSE_SORT), key, key)
{
// Don't use open ranges for partial key_segments
if (!(key_part->flag & HA_PART_KEY_SEG))
@@ -1998,7 +2002,7 @@ class SEL_ARG_GT: public SEL_ARG
*/
SEL_ARG_GT(THD *thd, const uchar *key,
const KEY_PART *key_part, Field *field, Item *value)
- :SEL_ARG(field, key, key)
+ :SEL_ARG(field, !(key_part->flag & HA_REVERSE_SORT), key, key)
{
// Don't use open ranges for partial key_segments
if ((!(key_part->flag & HA_PART_KEY_SEG)) &&
@@ -2016,8 +2020,8 @@ class SEL_ARG_GE: public SEL_ARG
Use this constructor if value->save_in_field() went precisely,
without any data rounding or truncation.
*/
- SEL_ARG_GE(const uchar *key, Field *field)
- :SEL_ARG(field, key, key)
+ SEL_ARG_GE(const uchar *key, Field *field, bool is_asc)
+ :SEL_ARG(field, is_asc, key, key)
{
max_flag= NO_MAX_RANGE;
}
@@ -2028,7 +2032,7 @@ class SEL_ARG_GE: public SEL_ARG
*/
SEL_ARG_GE(THD *thd, const uchar *key,
const KEY_PART *key_part, Field *field, Item *value)
- :SEL_ARG(field, key, key)
+ :SEL_ARG(field, !(key_part->flag & HA_REVERSE_SORT), key, key)
{
// Don't use open ranges for partial key_segments
if ((!(key_part->flag & HA_PART_KEY_SEG)) &&
@@ -2059,7 +2063,8 @@ SEL_ARG *SEL_ARG::clone(RANGE_OPT_PARAM *param, SEL_ARG *new_parent,
}
else
{
- if (!(tmp= new (param->mem_root) SEL_ARG(field,part, min_value,max_value,
+ if (!(tmp= new (param->mem_root) SEL_ARG(field, part, is_ascending,
+ min_value, max_value,
min_flag, max_flag, maybe_flag)))
return 0; // OOM
tmp->parent=new_parent;
@@ -2830,6 +2835,7 @@ int SQL_SELECT::test_quick_select(THD *thd, key_map keys_to_use,
}
trace_keypart.end();
trace_idx_details.add("usable", !unusable_has_desc_keyparts);
+ unusable_has_desc_keyparts= false;
if (unusable_has_desc_keyparts) // TODO MDEV-13756
{
key_parts= param.key[param.keys];
@@ -4420,12 +4426,14 @@ int find_used_partitions(PART_PRUNE_PARAM *ppar, SEL_ARG *key_tree)
key_tree->next_key_part->store_min_key(ppar->key,
&tmp_min_key,
&tmp_min_flag,
- ppar->last_part_partno);
+ ppar->last_part_partno,
+ true);
if (!tmp_max_flag)
key_tree->next_key_part->store_max_key(ppar->key,
&tmp_max_key,
&tmp_max_flag,
- ppar->last_part_partno);
+ ppar->last_part_partno,
+ false);
flag= tmp_min_flag | tmp_max_flag;
}
else
@@ -8671,7 +8679,8 @@ Item_func_null_predicate::get_mm_leaf(RANGE_OPT_PARAM *param,
if (!field->real_maybe_null())
DBUG_RETURN(type == ISNULL_FUNC ? &null_element : NULL);
SEL_ARG *tree;
- if (!(tree= new (alloc) SEL_ARG(field, is_null_string, is_null_string)))
+ bool is_asc= !(key_part->flag & HA_REVERSE_SORT);
+ if (!(tree= new (alloc) SEL_ARG(field, is_asc, is_null_string, is_null_string)))
DBUG_RETURN(0);
if (type == Item_func::ISNOTNULL_FUNC)
{
@@ -8771,7 +8780,8 @@ Item_func_like::get_mm_leaf(RANGE_OPT_PARAM *param,
int2store(min_str + maybe_null, min_length);
int2store(max_str + maybe_null, max_length);
}
- SEL_ARG *tree= new (param->mem_root) SEL_ARG(field, min_str, max_str);
+ bool is_asc= !(key_part->flag & HA_REVERSE_SORT);
+ SEL_ARG *tree= new (param->mem_root) SEL_ARG(field, is_asc, min_str, max_str);
DBUG_RETURN(tree);
}
@@ -9019,18 +9029,19 @@ SEL_ARG *Field::stored_field_make_mm_leaf(RANGE_OPT_PARAM *param,
if (!(str= make_key_image(param->mem_root, key_part)))
DBUG_RETURN(0);
+ bool is_asc= !(key_part->flag & HA_REVERSE_SORT);
switch (op) {
case SCALAR_CMP_LE:
- DBUG_RETURN(new (mem_root) SEL_ARG_LE(str, this));
+ DBUG_RETURN(new (mem_root) SEL_ARG_LE(str, this, is_asc));
case SCALAR_CMP_LT:
- DBUG_RETURN(new (mem_root) SEL_ARG_LT(thd, str, this, value));
+ DBUG_RETURN(new (mem_root) SEL_ARG_LT(thd, str, this, is_asc, value));
case SCALAR_CMP_GT:
DBUG_RETURN(new (mem_root) SEL_ARG_GT(thd, str, key_part, this, value));
case SCALAR_CMP_GE:
DBUG_RETURN(new (mem_root) SEL_ARG_GE(thd, str, key_part, this, value));
case SCALAR_CMP_EQ:
case SCALAR_CMP_EQUAL:
- DBUG_RETURN(new (mem_root) SEL_ARG(this, str, str));
+ DBUG_RETURN(new (mem_root) SEL_ARG(this, is_asc, str, str));
break;
}
DBUG_ASSERT(0);
@@ -9048,18 +9059,19 @@ SEL_ARG *Field::stored_field_make_mm_leaf_exact(RANGE_OPT_PARAM *param,
if (!(str= make_key_image(param->mem_root, key_part)))
DBUG_RETURN(0);
+ bool is_asc= !(key_part->flag & HA_REVERSE_SORT);
switch (op) {
case SCALAR_CMP_LE:
- DBUG_RETURN(new (param->mem_root) SEL_ARG_LE(str, this));
+ DBUG_RETURN(new (param->mem_root) SEL_ARG_LE(str, this, is_asc));
case SCALAR_CMP_LT:
- DBUG_RETURN(new (param->mem_root) SEL_ARG_LT(str, this));
+ DBUG_RETURN(new (param->mem_root) SEL_ARG_LT(str, this, is_asc));
case SCALAR_CMP_GT:
DBUG_RETURN(new (param->mem_root) SEL_ARG_GT(str, key_part, this));
case SCALAR_CMP_GE:
- DBUG_RETURN(new (param->mem_root) SEL_ARG_GE(str, this));
+ DBUG_RETURN(new (param->mem_root) SEL_ARG_GE(str, this, is_asc));
case SCALAR_CMP_EQ:
case SCALAR_CMP_EQUAL:
- DBUG_RETURN(new (param->mem_root) SEL_ARG(this, str, str));
+ DBUG_RETURN(new (param->mem_root) SEL_ARG(this, is_asc, str, str));
break;
}
DBUG_ASSERT(0);
@@ -11777,6 +11789,46 @@ get_quick_select(PARAM *param,uint idx,SEL_ARG *key_tree, uint mrr_flags,
}
+void SEL_ARG::store_next_min_max_keys(KEY_PART *key,
+ uchar **cur_min_key, uint *cur_min_flag,
+ uchar **cur_max_key, uint *cur_max_flag,
+ int *min_part, int *max_part)
+{
+ DBUG_ASSERT(next_key_part);
+ bool asc = next_key_part->is_ascending;
+
+ if (!get_min_flag())
+ {
+ if (asc)
+ {
+ *min_part += next_key_part->store_min_key(key, cur_min_key,
+ cur_min_flag, MAX_KEY, true);
+ }
+ else
+ {
+ uint tmp_flag = invert_min_flag(*cur_min_flag);
+ *min_part += next_key_part->store_max_key(key, cur_min_key, &tmp_flag,
+ MAX_KEY, true);
+ *cur_min_flag = invert_max_flag(tmp_flag);
+ }
+ }
+ if (!get_max_flag())
+ {
+ if (asc)
+ {
+ *max_part += next_key_part->store_max_key(key, cur_max_key,
+ cur_max_flag, MAX_KEY, false);
+ }
+ else
+ {
+ uint tmp_flag = invert_max_flag(*cur_max_flag);
+ *max_part += next_key_part->store_min_key(key, cur_max_key, &tmp_flag,
+ MAX_KEY, false);
+ *cur_max_flag = invert_min_flag(tmp_flag);
+ }
+ }
+}
+
/*
** Fix this to get all possible sub_ranges
*/
@@ -11790,17 +11842,19 @@ get_quick_keys(PARAM *param,QUICK_RANGE_SELECT *quick,KEY_PART *key,
int min_part= key_tree->part-1, // # of keypart values in min_key buffer
max_part= key_tree->part-1; // # of keypart values in max_key buffer
- if (key_tree->left != &null_element)
+ SEL_ARG *next_tree = key_tree->is_ascending ? key_tree->left : key_tree->right;
+ if (next_tree != &null_element)
{
- if (get_quick_keys(param,quick,key,key_tree->left,
+ if (get_quick_keys(param,quick,key,next_tree,
min_key,min_key_flag, max_key, max_key_flag))
return 1;
}
uchar *tmp_min_key=min_key,*tmp_max_key=max_key;
- min_part+= key_tree->store_min(key[key_tree->part].store_length,
- &tmp_min_key,min_key_flag);
- max_part+= key_tree->store_max(key[key_tree->part].store_length,
- &tmp_max_key,max_key_flag);
+
+ key_tree->store_min_max(key[key_tree->part].store_length,
+ &tmp_min_key, min_key_flag,
+ &tmp_max_key, max_key_flag,
+ &min_part, &max_part);
if (key_tree->next_key_part &&
key_tree->next_key_part->type == SEL_ARG::KEY_RANGE &&
@@ -11810,31 +11864,40 @@ get_quick_keys(PARAM *param,QUICK_RANGE_SELECT *quick,KEY_PART *key,
memcmp(min_key, max_key, (uint)(tmp_max_key - max_key))==0 &&
key_tree->min_flag==0 && key_tree->max_flag==0)
{
+ // psergey-note: simplified the parameters below as follows:
+ // min_key_flag | key_tree->min_flag -> min_key_flag
+ // max_key_flag | key_tree->max_flag -> max_key_flag
if (get_quick_keys(param,quick,key,key_tree->next_key_part,
- tmp_min_key, min_key_flag | key_tree->min_flag,
- tmp_max_key, max_key_flag | key_tree->max_flag))
+ tmp_min_key, min_key_flag,
+ tmp_max_key, max_key_flag))
return 1;
goto end; // Ugly, but efficient
}
{
- uint tmp_min_flag=key_tree->min_flag,tmp_max_flag=key_tree->max_flag;
- if (!tmp_min_flag)
- min_part+= key_tree->next_key_part->store_min_key(key,
- &tmp_min_key,
- &tmp_min_flag,
- MAX_KEY);
- if (!tmp_max_flag)
- max_part+= key_tree->next_key_part->store_max_key(key,
- &tmp_max_key,
- &tmp_max_flag,
- MAX_KEY);
+ uint tmp_min_flag= key_tree->get_min_flag();
+ uint tmp_max_flag= key_tree->get_max_flag();
+
+ key_tree->store_next_min_max_keys(key,
+ &tmp_min_key, &tmp_min_flag,
+ &tmp_max_key, &tmp_max_flag,
+ &min_part, &max_part);
flag=tmp_min_flag | tmp_max_flag;
}
}
else
{
- flag = (key_tree->min_flag & GEOM_FLAG) ?
- key_tree->min_flag : key_tree->min_flag | key_tree->max_flag;
+ if (key_tree->is_ascending)
+ {
+ flag= (key_tree->min_flag & GEOM_FLAG) ? key_tree->min_flag:
+ (key_tree->min_flag |
+ key_tree->max_flag);
+ }
+ else
+ {
+ // Invert flags for DESC keypart
+ flag= invert_min_flag(key_tree->min_flag) |
+ invert_max_flag(key_tree->max_flag);
+ }
}
/*
@@ -11895,8 +11958,9 @@ get_quick_keys(PARAM *param,QUICK_RANGE_SELECT *quick,KEY_PART *key,
return 1;
end:
- if (key_tree->right != &null_element)
- return get_quick_keys(param,quick,key,key_tree->right,
+ next_tree = key_tree->is_ascending ? key_tree->right : key_tree->left;
+ if (next_tree != &null_element)
+ return get_quick_keys(param,quick,key,next_tree,
min_key,min_key_flag,
max_key,max_key_flag);
return 0;
diff --git a/sql/opt_range.h b/sql/opt_range.h
index 1014176ecc5..6864a5c583a 100644
--- a/sql/opt_range.h
+++ b/sql/opt_range.h
@@ -54,6 +54,33 @@ struct KEY_PART {
};
+/**
+ A helper function to invert min flags to max flags for DESC key parts.
+ It changes NEAR_MIN, NO_MIN_RANGE to NEAR_MAX, NO_MAX_RANGE appropriately
+*/
+
+inline uint invert_min_flag(uint min_flag)
+{
+ uint max_flag_out = min_flag & ~(NEAR_MIN | NO_MIN_RANGE);
+ if (min_flag & NEAR_MIN) max_flag_out |= NEAR_MAX;
+ if (min_flag & NO_MIN_RANGE) max_flag_out |= NO_MAX_RANGE;
+ return max_flag_out;
+}
+
+
+/**
+ A helper function to invert max flags to min flags for DESC key parts.
+ It changes NEAR_MAX, NO_MAX_RANGE to NEAR_MIN, NO_MIN_RANGE appropriately
+*/
+
+inline uint invert_max_flag(uint max_flag)
+{
+ uint min_flag_out = max_flag & ~(NEAR_MAX | NO_MAX_RANGE);
+ if (max_flag & NEAR_MAX) min_flag_out |= NEAR_MIN;
+ if (max_flag & NO_MAX_RANGE) min_flag_out |= NO_MIN_RANGE;
+ return min_flag_out;
+}
+
class RANGE_OPT_PARAM;
/*
A construction block of the SEL_ARG-graph.
@@ -267,6 +294,8 @@ class RANGE_OPT_PARAM;
- it is a lot easier to compute than computing the number of ranges,
- it can be updated incrementally when performing AND/OR operations on
parts of the graph.
+
+ 6. For handling DESC keyparts, See HowRangeOptimizerHandlesDescKeyparts
*/
class SEL_ARG :public Sql_alloc
@@ -277,6 +306,11 @@ class SEL_ARG :public Sql_alloc
uint8 min_flag,max_flag,maybe_flag;
uint8 part; // Which key part
uint8 maybe_null;
+ /*
+ Whether the keypart is ascending or descending.
+ See HowRangeOptimizerHandlesDescKeyparts for details.
+ */
+ uint8 is_ascending;
/*
The ordinal number the least significant component encountered in
the ranges of the SEL_ARG tree (the first component has number 1)
@@ -327,11 +361,15 @@ class SEL_ARG :public Sql_alloc
SEL_ARG() {}
SEL_ARG(SEL_ARG &);
- SEL_ARG(Field *,const uchar *, const uchar *);
- SEL_ARG(Field *field, uint8 part, uchar *min_value, uchar *max_value,
+ SEL_ARG(Field *, bool is_asc, const uchar *, const uchar *);
+ SEL_ARG(Field *field, uint8 part, bool is_asc,
+ uchar *min_value, uchar *max_value,
uint8 min_flag, uint8 max_flag, uint8 maybe_flag);
+
+ /* This is used to construct degenerate SEL_ARGS like ALWAYS, IMPOSSIBLE, etc */
SEL_ARG(enum Type type_arg)
- :min_flag(0), max_part_no(0) /* first key part means 1. 0 mean 'no parts'*/,
+ :min_flag(0), is_ascending(false),
+ max_part_no(0) /* first key part means 1. 0 mean 'no parts'*/,
elements(1),use_count(1),left(0),right(0),
next_key_part(0), color(BLACK), type(type_arg), weight(1)
{}
@@ -409,19 +447,20 @@ class SEL_ARG :public Sql_alloc
{
new_max=arg->max_value; flag_max=arg->max_flag;
}
- return new (thd->mem_root) SEL_ARG(field, part, new_min, new_max, flag_min,
+ return new (thd->mem_root) SEL_ARG(field, part, is_ascending,
+ new_min, new_max, flag_min,
flag_max,
MY_TEST(maybe_flag && arg->maybe_flag));
}
SEL_ARG *clone_first(SEL_ARG *arg)
{ // min <= X < arg->min
- return new SEL_ARG(field,part, min_value, arg->min_value,
+ return new SEL_ARG(field, part, is_ascending, min_value, arg->min_value,
min_flag, arg->min_flag & NEAR_MIN ? 0 : NEAR_MAX,
maybe_flag | arg->maybe_flag);
}
SEL_ARG *clone_last(SEL_ARG *arg)
{ // min <= X <= key_max
- return new SEL_ARG(field, part, min_value, arg->max_value,
+ return new SEL_ARG(field, part, is_ascending, min_value, arg->max_value,
min_flag, arg->max_flag, maybe_flag | arg->maybe_flag);
}
SEL_ARG *clone(RANGE_OPT_PARAM *param, SEL_ARG *new_parent, SEL_ARG **next);
@@ -504,6 +543,56 @@ class SEL_ARG :public Sql_alloc
return 0;
}
+ /* Save minimum and maximum, taking index order into account */
+ void store_min_max(uint length,
+ uchar **min_key, uint min_flag,
+ uchar **max_key, uint max_flag,
+ int *min_part, int *max_part)
+ {
+ if (is_ascending) {
+ *min_part += store_min(length, min_key, min_flag);
+ *max_part += store_max(length, max_key, max_flag);
+ } else {
+ *max_part += store_min(length, max_key, min_flag);
+ *min_part += store_max(length, min_key, max_flag);
+ }
+ }
+ /*
+ Get the flag for range's starting endpoint, taking index order into
+ account.
+ */
+ uint get_min_flag()
+ {
+ return (is_ascending ? min_flag : invert_max_flag(max_flag));
+ }
+ /*
+ Get the flag for range's starting endpoint, taking index order into
+ account.
+ */
+ uint get_max_flag()
+ {
+ return (is_ascending ? max_flag : invert_min_flag(min_flag));
+ }
+ /* Get the previous interval, taking index order into account */
+ inline SEL_ARG* index_order_prev()
+ {
+ return is_ascending? prev: next;
+ }
+ /* Get the next interval, taking index order into account */
+ inline SEL_ARG* index_order_next()
+ {
+ return is_ascending? next: prev;
+ }
+
+ /*
+ Produce a single multi-part interval, taking key part ordering into
+ account.
+ */
+ void store_next_min_max_keys(KEY_PART *key, uchar **cur_min_key,
+ uint *cur_min_flag, uchar **cur_max_key,
+ uint *cur_max_flag, int *min_part,
+ int *max_part);
+
/*
Returns a number of keypart values appended to the key buffer
for min key and max key. This function is used by both Range
@@ -516,7 +605,8 @@ class SEL_ARG :public Sql_alloc
int store_min_key(KEY_PART *key,
uchar **range_key,
uint *range_key_flag,
- uint last_part)
+ uint last_part,
+ bool start_key)
{
SEL_ARG *key_tree= first();
uint res= key_tree->store_min(key[key_tree->part].store_length,
@@ -525,15 +615,26 @@ class SEL_ARG :public Sql_alloc
if (!res)
return 0;
*range_key_flag|= key_tree->min_flag;
- if (key_tree->next_key_part &&
- key_tree->next_key_part->type == SEL_ARG::KEY_RANGE &&
+ SEL_ARG *nkp= key_tree->next_key_part;
+ if (nkp && nkp->type == SEL_ARG::KEY_RANGE &&
key_tree->part != last_part &&
- key_tree->next_key_part->part == key_tree->part+1 &&
+ nkp->part == key_tree->part+1 &&
!(*range_key_flag & (NO_MIN_RANGE | NEAR_MIN)))
- res+= key_tree->next_key_part->store_min_key(key,
- range_key,
- range_key_flag,
- last_part);
+ {
+ const bool asc = nkp->is_ascending;
+ if (start_key == asc)
+ {
+ res+= nkp->store_min_key(key, range_key, range_key_flag, last_part,
+ start_key);
+ }
+ else
+ {
+ uint tmp_flag = invert_min_flag(*range_key_flag);
+ res += nkp->store_max_key(key, range_key, &tmp_flag, last_part,
+ start_key);
+ *range_key_flag = invert_max_flag(tmp_flag);
+ }
+ }
return res;
}
@@ -541,7 +642,8 @@ class SEL_ARG :public Sql_alloc
int store_max_key(KEY_PART *key,
uchar **range_key,
uint *range_key_flag,
- uint last_part)
+ uint last_part,
+ bool start_key)
{
SEL_ARG *key_tree= last();
uint res=key_tree->store_max(key[key_tree->part].store_length,
@@ -549,15 +651,26 @@ class SEL_ARG :public Sql_alloc
if (!res)
return 0;
*range_key_flag|= key_tree->max_flag;
- if (key_tree->next_key_part &&
- key_tree->next_key_part->type == SEL_ARG::KEY_RANGE &&
+ SEL_ARG *nkp= key_tree->next_key_part;
+ if (nkp && nkp->type == SEL_ARG::KEY_RANGE &&
key_tree->part != last_part &&
- key_tree->next_key_part->part == key_tree->part+1 &&
+ nkp->part == key_tree->part+1 &&
!(*range_key_flag & (NO_MAX_RANGE | NEAR_MAX)))
- res+= key_tree->next_key_part->store_max_key(key,
- range_key,
- range_key_flag,
- last_part);
+ {
+ const bool asc = nkp->is_ascending;
+ if ((!start_key && asc) || (start_key && !asc))
+ {
+ res += nkp->store_max_key(key, range_key, range_key_flag, last_part,
+ start_key);
+ }
+ else
+ {
+ uint tmp_flag = invert_max_flag(*range_key_flag);
+ res += nkp->store_min_key(key, range_key, &tmp_flag, last_part,
+ start_key);
+ *range_key_flag = invert_min_flag(tmp_flag);
+ }
+ }
return res;
}
@@ -661,13 +774,83 @@ class SEL_ARG :public Sql_alloc
SEL_ARG *clone_tree(RANGE_OPT_PARAM *param);
};
+/*
+ HowRangeOptimizerHandlesDescKeyparts
+ ====================================
+
+ Starting with MySQL-8.0 and MariaDB 10.8, index key parts may be descending,
+ for example:
+
+ INDEX idx1(col1, col2 DESC, col3, col4 DESC)
+
+ Range Optimizer handles this as follows:
+
+ The SEL_ARG object has SEL_ARG::is_ascending which specifies whether the
+ keypart is ascending.
+
+ Other than that, the SEL_ARG graph is built without any regard to DESC
+ keyparts.
+
+ For example, for an index
+
+ INDEX idx2(kp1 DESC, kp2)
+
+ and range
+
+ kp1 BETWEEN 10 and 20 (RANGE-1)
+
+ the SEL_ARG will have min_value=10, max_value=20, is_ascending=false.
+
+ The ordering of key parts is taken into account when SEL_ARG graph is
+ linearized to ranges, in sel_arg_range_seq_next() and get_quick_keys().
+
+ The storage engine expects the first bound to be the first in the index and
+ the last bound to be the last, that is, for (RANGE-1) we will flip min and
+ max and generate these key_range structures:
+
+ start.key='20' , end.key='10'
+
+ See SEL_ARG::store_min_max(). The flag values are flipped as well, see
+ SEL_ARG::get_min_flag(), get_max_flag().
+
+ == Handling multiple key parts ==
+
+ For multi-part keys, the order of key parts has an effect on which ranges are
+ generated. Consider
+
+ kp1 >= 10 AND kp2 >'foo'
+
+ for INDEX(kp1 ASC, kp2 ASC) the range will be
+
+ (kp1, kp2) > (10, 'foo')
+
+ while for INDEX(kp1 ASC, kp2 DESC) it will be just
+
+ kp1 >= 10
+
+ Another example:
+
+ (kp1 BETWEEN 10 AND 20) AND (kp2 BETWEEN 'foo' AND 'quux')
+
+ with INDEX (kp1 ASC, kp2 ASC) will generate
+
+ (10, 'foo') <= (kp1, kp2) < (20, 'quux')
+
+ while with index INDEX (kp1 ASC, kp2 DESC) it will generate
+
+ (10, 'quux') <= (kp1, kp2) < (20, 'foo')
+
+ This is again achieved by sel_arg_range_seq_next() and get_quick_keys()
+ flipping SEL_ARG's min,max, their flags and next/prev as needed.
+*/
+
extern MYSQL_PLUGIN_IMPORT SEL_ARG null_element;
class SEL_ARG_IMPOSSIBLE: public SEL_ARG
{
public:
SEL_ARG_IMPOSSIBLE(Field *field)
- :SEL_ARG(field, 0, 0)
+ :SEL_ARG(field, false, 0, 0)
{
type= SEL_ARG::IMPOSSIBLE;
}
diff --git a/sql/opt_range_mrr.cc b/sql/opt_range_mrr.cc
index 20413f5df63..8877e15d5b5 100644
--- a/sql/opt_range_mrr.cc
+++ b/sql/opt_range_mrr.cc
@@ -34,7 +34,7 @@ typedef struct st_range_seq_entry
uint min_key_flag, max_key_flag;
/* Number of key parts */
- uint min_key_parts, max_key_parts;
+ int min_key_parts, max_key_parts;
SEL_ARG *key_tree;
} RANGE_SEQ_ENTRY;
@@ -105,13 +105,14 @@ static void step_down_to(SEL_ARG_RANGE_SEQ *arg, SEL_ARG *key_tree)
cur->max_key_parts= prev->max_key_parts;
uint16 stor_length= arg->param->key[arg->keyno][key_tree->part].store_length;
- cur->min_key_parts += key_tree->store_min(stor_length, &cur->min_key,
- prev->min_key_flag);
- cur->max_key_parts += key_tree->store_max(stor_length, &cur->max_key,
- prev->max_key_flag);
- cur->min_key_flag= prev->min_key_flag | key_tree->min_flag;
- cur->max_key_flag= prev->max_key_flag | key_tree->max_flag;
+ key_tree->store_min_max(stor_length,
+ &cur->min_key, prev->min_key_flag,
+ &cur->max_key, prev->max_key_flag,
+ &cur->min_key_parts, &cur->max_key_parts);
+
+ cur->min_key_flag= prev->min_key_flag | key_tree->get_min_flag();
+ cur->max_key_flag= prev->max_key_flag | key_tree->get_max_flag();
if (key_tree->is_null_interval())
cur->min_key_flag |= NULL_RANGE;
@@ -165,12 +166,12 @@ bool sel_arg_range_seq_next(range_seq_t rseq, KEY_MULTI_RANGE *range)
/* Ok, we're at some "full tuple" position in the tree */
/* Step down if we can */
- if (key_tree->next && key_tree->next != &null_element)
+ if (key_tree->index_order_next() && key_tree->index_order_next() != &null_element)
{
//step down; (update the tuple, we'll step right and stay there)
seq->i--;
- step_down_to(seq, key_tree->next);
- key_tree= key_tree->next;
+ step_down_to(seq, key_tree->index_order_next());
+ key_tree= key_tree->index_order_next();
seq->is_ror_scan= FALSE;
goto walk_right_n_up;
}
@@ -185,12 +186,12 @@ bool sel_arg_range_seq_next(range_seq_t rseq, KEY_MULTI_RANGE *range)
key_tree= seq->stack[seq->i].key_tree;
/* Step down if we can */
- if (key_tree->next && key_tree->next != &null_element)
+ if (key_tree->index_order_next() && key_tree->index_order_next() != &null_element)
{
// Step down; update the tuple
seq->i--;
- step_down_to(seq, key_tree->next);
- key_tree= key_tree->next;
+ step_down_to(seq, key_tree->index_order_next());
+ key_tree= key_tree->index_order_next();
break;
}
}
@@ -214,16 +215,10 @@ bool sel_arg_range_seq_next(range_seq_t rseq, KEY_MULTI_RANGE *range)
!key_tree->min_flag && !key_tree->max_flag))
{
seq->is_ror_scan= FALSE;
- if (!key_tree->min_flag)
- cur->min_key_parts +=
- key_tree->next_key_part->store_min_key(seq->param->key[seq->keyno],
- &cur->min_key,
- &cur->min_key_flag, MAX_KEY);
- if (!key_tree->max_flag)
- cur->max_key_parts +=
- key_tree->next_key_part->store_max_key(seq->param->key[seq->keyno],
- &cur->max_key,
- &cur->max_key_flag, MAX_KEY);
+ key_tree->store_next_min_max_keys(seq->param->key[seq->keyno],
+ &cur->min_key, &cur->min_key_flag,
+ &cur->max_key, &cur->max_key_flag,
+ &cur->min_key_parts, &cur->max_key_parts);
break;
}
}
@@ -235,10 +230,11 @@ bool sel_arg_range_seq_next(range_seq_t rseq, KEY_MULTI_RANGE *range)
key_tree= key_tree->next_key_part;
walk_up_n_right:
- while (key_tree->prev && key_tree->prev != &null_element)
+ while (key_tree->index_order_prev() &&
+ key_tree->index_order_prev() != &null_element)
{
/* Step up */
- key_tree= key_tree->prev;
+ key_tree= key_tree->index_order_prev();
}
step_down_to(seq, key_tree);
}
