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WL#2985 "Partition Pruning": post-review fixes: Better comments

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sergefp@mysql.com
2005-12-29 09:32:46 +03:00
parent 328f8fa735
commit f2d603c245
4 changed files with 48 additions and 17 deletions
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15
mysql-test/r/partition_pruning.result
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@ -259,3 +259,18 @@ explain partitions select * from t1 where a is not null;
id select_type table partitions type possible_keys key key_len ref rows Extra
1 SIMPLE t1 p0,p1 ALL NULL NULL NULL NULL 2 Using where
drop table t1;
create table t1 (a int not null, b int not null, key(a), key(b))
partition by hash(a) partitions 4;
insert into t1 values (1,1),(2,2),(3,3),(4,4);
explain partitions
select * from t1 X, t1 Y
where X.b = Y.b and (X.a=1 or X.a=2) and (Y.a=2 or Y.a=3);
id select_type table partitions type possible_keys key key_len ref rows Extra
1 SIMPLE X p1,p2 ALL a,b NULL NULL NULL 4 Using where
1 SIMPLE Y p2,p3 ref a,b b 4 test.X.b 2 Using where
explain partitions
select * from t1 X, t1 Y where X.a = Y.a and (X.a=1 or X.a=2);
id select_type table partitions type possible_keys key key_len ref rows Extra
1 SIMPLE X p1,p2 ALL a NULL NULL NULL 4 Using where
1 SIMPLE Y p1,p2 ref a a 4 test.X.a 2
drop table t1;

15
mysql-test/t/partition_pruning.test
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@ -230,9 +230,22 @@ create table t1 (a int) partition by hash(a) partitions 2;
insert into t1 values (1),(2);
explain partitions select * from t1 where a is null;
# this selects both
# this uses both partitions
explain partitions select * from t1 where a is not null;
drop table t1;
# Join tests
create table t1 (a int not null, b int not null, key(a), key(b))
partition by hash(a) partitions 4;
insert into t1 values (1,1),(2,2),(3,3),(4,4);
explain partitions
select * from t1 X, t1 Y
where X.b = Y.b and (X.a=1 or X.a=2) and (Y.a=2 or Y.a=3);
explain partitions
select * from t1 X, t1 Y where X.a = Y.a and (X.a=1 or X.a=2);
drop table t1;
# No tests for NULLs in RANGE(monotonic_expr()) - they depend on BUG#15447
# being fixed.

4
sql/handler.h
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@ -567,9 +567,9 @@ public:
*/
get_subpart_id_func get_subpartition_id;
/* NULL-terminated list of fields used in partitioned expression */
/* NULL-terminated array of fields used in partitioned expression */
Field **part_field_array;
/* NULL-terminated list of fields used in subpartitioned expression */
/* NULL-terminated array of fields used in subpartitioned expression */
Field **subpart_field_array;
/*

29
sql/opt_range.cc
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@ -2246,11 +2246,11 @@ typedef struct st_part_prune_param
/***************************************************************
Following fields are used to store an 'iterator' that can be
used to obtain a set of used artitions.
used to obtain a set of used partitions.
**************************************************************/
/*
Start and end+1 partition "numbers". They can have two meanings depending
depending of the value of part_num_to_part_id:
of the value of part_num_to_part_id:
part_num_to_part_id_range - numbers are partition ids
part_num_to_part_id_list - numbers are indexes in part_info->list_array
*/
@ -2536,7 +2536,7 @@ static uint32 part_num_to_part_id_list(PART_PRUNE_PARAM* ppar, uint32 num)
List<SEL_IMERGE> represents "imerge1 AND imerge2 AND ...".
The set of used partitions is an intersection of used partitions sets
for imerge_{i}.
We accumulate this intersection a separate bitmap.
We accumulate this intersection in a separate bitmap.
RETURN
See find_used_partitions()
@ -2554,7 +2554,7 @@ static int find_used_partitions_imerge_list(PART_PRUNE_PARAM *ppar,
bitmap_bytes)))
{
/*
Fallback, process just first SEL_IMERGE. This can leave us with more
Fallback, process just the first SEL_IMERGE. This can leave us with more
partitions marked as used then actually needed.
*/
return find_used_partitions_imerge(ppar, merges.head());
@ -2623,20 +2623,20 @@ int find_used_partitions_imerge(PART_PRUNE_PARAM *ppar, SEL_IMERGE *imerge)
/*
Recursively walk the SEL_ARG tree, find/mark partitions that need to be used
Collect partitioning ranges for the SEL_ARG tree and mark partitions as used
SYNOPSIS
find_used_partitions()
ppar Partition pruning context.
key_tree Intervals tree to perform pruning for.
key_tree SEL_ARG range tree to perform pruning for
DESCRIPTION
This function
* recursively walks the SEL_ARG* tree collecting partitioning
"intervals";
* finds the partitions one needs to use to get rows in these intervals;
* marks these partitions as used.
* recursively walks the SEL_ARG* tree collecting partitioning "intervals"
* finds the partitions one needs to use to get rows in these intervals
* marks these partitions as used
NOTES
WHAT IS CONSIDERED TO BE "INTERVALS"
A partition pruning "interval" is equivalent to condition in one of the
forms:
@ -2687,7 +2687,7 @@ int find_used_partitions(PART_PRUNE_PARAM *ppar, SEL_ARG *key_tree)
{
/*
Partitioning is done by RANGE|INTERVAL(monotonic_expr(fieldX)), and
we got "const1 < fieldX < const2" interval.
we got "const1 CMP fieldX CMP const2" interval
*/
DBUG_EXECUTE("info", dbug_print_segment_range(key_tree,
ppar->range_param.
@ -2761,7 +2761,7 @@ int find_used_partitions(PART_PRUNE_PARAM *ppar, SEL_ARG *key_tree)
DBUG_EXECUTE("info", dbug_print_singlepoint_range(ppar->arg_stack,
ppar->part_fields););
uint32 part_id;
/* then find in which partition the {const1, ...,constN} tuple goes */
/* Find in which partition the {const1, ...,constN} tuple goes */
if (ppar->get_top_partition_id_func(ppar->part_info, &part_id))
{
res= 0; /* No satisfying partitions */
@ -2843,7 +2843,10 @@ process_next_key_part:
if (set_full_part_if_bad_ret)
{
/* Restore the "used partition iterator" to its default */
/*
Restore the "used partitions iterator" to the default setting that
specifies iteration over all partitions.
*/
ppar->part_num_to_part_id= part_num_to_part_id_range;
ppar->start_part_num= 0;
ppar->end_part_num= ppar->part_info->no_parts;