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Fixed calculation of JOIN_CACHE::max_records

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The old code did set max_records to either number_of_rows
(partial_join_cardinality) or memory size (join_buffer_space_limit)
which did not make sense.

Fixed by setting max_records to number of rows that fits into
join_buffer_size.

Other things:
- Initialize buffer cache values in JOIN_CACHE constructors (safety)

Reviewer: Sergei Petrunia <sergey@mariadb.com>
This commit is contained in:
Monty 2023-05-04 12:43:18 +03:00
parent 08a4732860
commit 5fd46be5a7
3 changed files with 18 additions and 18 deletions
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2
mysql-test/main/join_cache.result
View File

@ -3781,9 +3781,9 @@ id1 num3 text1 id4 id3 dummy
228808822 6 CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC 826928662 935693782 0
228808822 18 CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC 826928662 935693782 0
228808822 1 CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC 826928662 935693782 0
228808822 3 CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC 826928662 935693782 0
228808822 17 CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC 826928662 935693782 0
228808822 50 CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC 826928662 935693782 0
228808822 3 CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC 826928662 935693782 0
228808822 4 CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC 826928662 935693782 0
228808822 89 CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC 2381969632 2482416112 0
228808822 19 CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC 2381969632 2482416112 0

24
sql/sql_join_cache.cc
View File

@ -634,7 +634,7 @@ void JOIN_CACHE::create_remaining_fields()
/*
Calculate and set all cache constants
Calculate and set all cache constants
SYNOPSIS
set_constants()
@ -829,6 +829,12 @@ size_t JOIN_CACHE::get_max_join_buffer_size(bool optimize_buff_size)
size_t max_sz;
size_t min_sz= get_min_join_buffer_size();
size_t len= 0;
double max_records, partial_join_cardinality=
(join_tab-1)->get_partial_join_cardinality();
size_t limit_sz= (size_t) join->thd->variables.join_buff_size;
/* Expected join buffer space used for one record */
size_t space_per_record;
for (JOIN_TAB *tab= start_tab; tab != join_tab;
tab= next_linear_tab(join, tab, WITHOUT_BUSH_ROOTS))
{
@ -839,13 +845,17 @@ size_t JOIN_CACHE::get_max_join_buffer_size(bool optimize_buff_size)
len+= get_max_key_addon_space_per_record() + avg_aux_buffer_incr;
space_per_record= len;
size_t limit_sz= (size_t)join->thd->variables.join_buff_size;
/* Note that space_per_record can be 0 if no table fields where used */
max_records= (double) (limit_sz / MY_MAX(space_per_record, 1));
set_if_smaller(max_records, partial_join_cardinality);
set_if_bigger(max_records, 10.0);
if (!optimize_buff_size)
max_sz= limit_sz;
else
{
if (limit_sz / max_records > space_per_record)
max_sz= space_per_record * max_records;
if ((size_t) (limit_sz / max_records) > space_per_record)
max_sz= space_per_record * (size_t) max_records;
else
max_sz= limit_sz;
max_sz+= pack_length_with_blob_ptrs;
@ -855,7 +865,7 @@ size_t JOIN_CACHE::get_max_join_buffer_size(bool optimize_buff_size)
max_buff_size= max_sz;
}
return max_buff_size;
}
}
/*
@ -895,14 +905,10 @@ int JOIN_CACHE::alloc_buffer()
join->thd->variables.join_buff_space_limit;
bool optimize_buff_size=
optimizer_flag(join->thd, OPTIMIZER_SWITCH_OPTIMIZE_JOIN_BUFFER_SIZE);
double partial_join_cardinality= (join_tab-1)->get_partial_join_cardinality();
buff= NULL;
min_buff_size= 0;
max_buff_size= 0;
min_records= 1;
max_records= (size_t) (partial_join_cardinality <= join_buff_space_limit ?
(ulonglong) partial_join_cardinality : join_buff_space_limit);
set_if_bigger(max_records, 10);
min_buff_size= get_min_join_buffer_size();
buff_size= get_max_join_buffer_size(optimize_buff_size);

10
sql/sql_join_cache.h
View File

@ -248,9 +248,6 @@ protected:
/* The expected size of the space per record in the auxiliary buffer */
size_t avg_aux_buffer_incr;
/* Expected join buffer space used for one record */
size_t space_per_record;
/* Pointer to the beginning of the join buffer */
uchar *buff;
/*
@ -272,11 +269,6 @@ protected:
the minimal size equal to min_buff_size
*/
size_t min_records;
/*
The maximum expected number of records to be put in the join buffer
at one refill
*/
size_t max_records;
/*
Pointer to the current position in the join buffer.
@ -542,6 +534,7 @@ protected:
join_tab= tab;
prev_cache= next_cache= 0;
buff= 0;
min_buff_size= max_buff_size= 0; // Caches
}
/*
@ -557,6 +550,7 @@ protected:
next_cache= 0;
prev_cache= prev;
buff= 0;
min_buff_size= max_buff_size= 0; // Caches
if (prev)
prev->next_cache= this;
}