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MWL#17: Table elimination 

- Move eliminate_tables() to before constant table detection. 
- First code for benchmark

sql-bench/test-table-elimination.sh:
  MWL#17: Table elimination
  - sql-bench "Benchmark", incomplete
sql/sql_select.cc:
  MWL#17: Table elimination
  - Move eliminate_tables() to before constant table detection, this will allow
    to spare const table reads (at a cost of not being able to take advantage of 
    tables that are constant because they have no records, but this case is of 
    lesser importance)
pull/843/head
Sergey Petrunia 17 years ago
parent
6b4727dcb9
commit
d8640e3eae
2 changed files with 338 additions and 11 deletions
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  1. 320
      sql-bench/test-table-elimination.sh
  2. 29
      sql/sql_select.cc

320
sql-bench/test-table-elimination.sh
View File

@ -0,0 +1,320 @@
#!@PERL@
# Test of table elimination feature
use Cwd;
use DBI;
use Getopt::Long;
use Benchmark;
$opt_loop_count=100000;
$opt_medium_loop_count=10000;
$opt_small_loop_count=100;
$pwd = cwd(); $pwd = "." if ($pwd eq '');
require "$pwd/bench-init.pl" || die "Can't read Configuration file: $!\n";
if ($opt_small_test)
{
$opt_loop_count/=10;
$opt_medium_loop_count/=10;
$opt_small_loop_count/=10;
}
print "Testing table elimination feature\n";
print "The test table has $opt_loop_count rows.\n\n";
# A query to get the recent versions of all attributes:
$select_current_full_facts="
select
F.id, A1.attr1, A2.attr2
from
elim_facts F
left join elim_attr1 A1 on A1.id=F.id
left join elim_attr2 A2 on A2.id=F.id and
A2.fromdate=(select MAX(fromdate) from
elim_attr2 where id=A2.id);
";
$select_current_full_facts="
select
F.id, A1.attr1, A2.attr2
from
elim_facts F
left join elim_attr1 A1 on A1.id=F.id
left join elim_attr2 A2 on A2.id=F.id and
A2.fromdate=(select MAX(fromdate) from
elim_attr2 where id=F.id);
";
# TODO: same as above but for some given date also?
# TODO:
####
#### Connect and start timeing
####
$dbh = $server->connect();
$start_time=new Benchmark;
####
#### Create needed tables
####
goto select_test if ($opt_skip_create);
print "Creating tables\n";
$dbh->do("drop table elim_facts" . $server->{'drop_attr'});
$dbh->do("drop table elim_attr1" . $server->{'drop_attr'});
$dbh->do("drop table elim_attr2" . $server->{'drop_attr'});
# The facts table
do_many($dbh,$server->create("elim_facts",
["id integer"],
["primary key (id)"]));
# Attribute1, non-versioned
do_many($dbh,$server->create("elim_attr1",
["id integer",
"attr1 integer"],
["primary key (id)",
"key (attr1)"]));
# Attribute1, time-versioned
do_many($dbh,$server->create("elim_attr2",
["id integer",
"attr2 integer",
"fromdate date"],
["primary key (id, fromdate)",
"key (attr2,fromdate)"]));
#NOTE: ignoring: if ($limits->{'views'})
$dbh->do("drop view elim_current_facts");
$dbh->do("create view elim_current_facts as $select_current_full_facts");
if ($opt_lock_tables)
{
do_query($dbh,"LOCK TABLES elim_facts, elim_attr1, elim_attr2 WRITE");
}
if ($opt_fast && defined($server->{vacuum}))
{
$server->vacuum(1,\$dbh);
}
####
#### Fill the facts table
####
$n_facts= $opt_loop_count;
if ($opt_fast && $server->{transactions})
{
$dbh->{AutoCommit} = 0;
}
print "Inserting $n_facts rows into facts table\n";
$loop_time=new Benchmark;
$query="insert into elim_facts values (";
for ($id=0; $id < $n_facts ; $id++)
{
do_query($dbh,"$query $id)");
}
if ($opt_fast && $server->{transactions})
{
$dbh->commit;
$dbh->{AutoCommit} = 1;
}
$end_time=new Benchmark;
print "Time to insert ($n_facts): " .
timestr(timediff($end_time, $loop_time),"all") . "\n\n";
####
#### Fill attr1 table
####
if ($opt_fast && $server->{transactions})
{
$dbh->{AutoCommit} = 0;
}
print "Inserting $n_facts rows into attr1 table\n";
$loop_time=new Benchmark;
$query="insert into elim_attr1 values (";
for ($id=0; $id < $n_facts ; $id++)
{
$attr1= ceil(rand($n_facts));
do_query($dbh,"$query $id, $attr1)");
}
if ($opt_fast && $server->{transactions})
{
$dbh->commit;
$dbh->{AutoCommit} = 1;
}
$end_time=new Benchmark;
print "Time to insert ($n_facts): " .
timestr(timediff($end_time, $loop_time),"all") . "\n\n";
####
#### Fill attr2 table
####
if ($opt_fast && $server->{transactions})
{
$dbh->{AutoCommit} = 0;
}
print "Inserting $n_facts rows into attr2 table\n";
$loop_time=new Benchmark;
for ($id=0; $id < $n_facts ; $id++)
{
# Two values for each $id - current one and obsolete one.
$attr1= ceil(rand($n_facts));
$query="insert into elim_attr2 values ($id, $attr1, now())";
do_query($dbh,$query);
$query="insert into elim_attr2 values ($id, $attr1, '2009-01-01')";
do_query($dbh,$query);
}
if ($opt_fast && $server->{transactions})
{
$dbh->commit;
$dbh->{AutoCommit} = 1;
}
$end_time=new Benchmark;
print "Time to insert ($n_facts): " .
timestr(timediff($end_time, $loop_time),"all") . "\n\n";
####
#### Finalize the database population
####
if ($opt_lock_tables)
{
do_query($dbh,"UNLOCK TABLES");
}
if ($opt_fast && defined($server->{vacuum}))
{
$server->vacuum(0,\$dbh,["elim_facts", "elim_attr1", "elim_attr2"]);
}
if ($opt_lock_tables)
{
do_query($dbh,"LOCK TABLES elim_facts, elim_attr1, elim_attr2 WRITE");
}
####
#### Do some selects on the table
####
select_test:
#
# The selects will be:
# - N pk-lookups with all attributes
# - pk-attribute-based lookup
# - latest-attribute value based lookup.
###
### Bare facts select:
###
print "testing bare facts facts table\n";
$loop_time=new Benchmark;
$rows=0;
for ($i=0 ; $i < $opt_medium_loop_count ; $i++)
{
$val= ceil(rand($n_facts));
$rows+=fetch_all_rows($dbh,"select * from elim_facts where id=$val");
}
$count=$i;
$end_time=new Benchmark;
print "time for select_bare_facts ($count:$rows): " .
timestr(timediff($end_time, $loop_time),"all") . "\n";
###
### Full facts select, no elimination:
###
print "testing full facts facts table\n";
$loop_time=new Benchmark;
$rows=0;
for ($i=0 ; $i < $opt_medium_loop_count ; $i++)
{
$val= rand($n_facts);
$rows+=fetch_all_rows($dbh,"select * from elim_current_facts where id=$val");
}
$count=$i;
$end_time=new Benchmark;
print "time for select_two_attributes ($count:$rows): " .
timestr(timediff($end_time, $loop_time),"all") . "\n";
###
### Now with elimination: select only only one fact
###
print "testing selection of one attribute\n";
$loop_time=new Benchmark;
$rows=0;
for ($i=0 ; $i < $opt_medium_loop_count ; $i++)
{
$val= rand($n_facts);
$rows+=fetch_all_rows($dbh,"select id, attr1 from elim_current_facts where id=$val");
}
$count=$i;
$end_time=new Benchmark;
print "time for select_one_attribute ($count:$rows): " .
timestr(timediff($end_time, $loop_time),"all") . "\n";
###
### Now with elimination: select only only one fact
###
print "testing selection of one attribute\n";
$loop_time=new Benchmark;
$rows=0;
for ($i=0 ; $i < $opt_medium_loop_count ; $i++)
{
$val= rand($n_facts);
$rows+=fetch_all_rows($dbh,"select id, attr2 from elim_current_facts where id=$val");
}
$count=$i;
$end_time=new Benchmark;
print "time for select_one_attribute ($count:$rows): " .
timestr(timediff($end_time, $loop_time),"all") . "\n";
###
### TODO...
###
;
####
#### End of benchmark
####
if ($opt_lock_tables)
{
do_query($dbh,"UNLOCK TABLES");
}
if (!$opt_skip_delete)
{
do_query($dbh,"drop table elim_facts, elim_attr1, elim_attr2" . $server->{'drop_attr'});
}
if ($opt_fast && defined($server->{vacuum}))
{
$server->vacuum(0,\$dbh);
}
$dbh->disconnect; # close connection
end_benchmark($start_time);

29
sql/sql_select.cc
View File

@ -2959,22 +2959,28 @@ make_join_statistics(JOIN *join, TABLE_LIST *tables_arg, COND *conds,
/* Read tables with 0 or 1 rows (system tables) */
join->const_table_map= 0;
eliminate_tables(join, &const_count, &found_const_table_map);
join->const_table_map= found_const_table_map;
for (POSITION *p_pos=join->positions, *p_end=p_pos+const_count;
p_pos < p_end ;
p_pos++)
{
int tmp;
s= p_pos->table;
s->type=JT_SYSTEM;
join->const_table_map|=s->table->map;
if ((tmp=join_read_const_table(s, p_pos)))
if (! (s->table->map & join->eliminated_tables))
{
if (tmp > 0)
goto error; // Fatal error
int tmp;
s->type=JT_SYSTEM;
join->const_table_map|=s->table->map;
if ((tmp=join_read_const_table(s, p_pos)))
{
if (tmp > 0)
goto error; // Fatal error
}
else
found_const_table_map|= s->table->map;
}
else
found_const_table_map|= s->table->map;
}
/* loop until no more const tables are found */
@ -2999,7 +3005,8 @@ make_join_statistics(JOIN *join, TABLE_LIST *tables_arg, COND *conds,
substitution of a const table the key value happens to be null
then we can state that there are no matches for this equi-join.
*/
if ((keyuse= s->keyuse) && *s->on_expr_ref && !s->embedding_map)
if ((keyuse= s->keyuse) && *s->on_expr_ref && !s->embedding_map &&
!(table->map & join->eliminated_tables))
{
/*
When performing an outer join operation if there are no matching rows
@ -3135,7 +3142,7 @@ make_join_statistics(JOIN *join, TABLE_LIST *tables_arg, COND *conds,
}
//psergey-todo: table elimination
eliminate_tables(join, &const_count, &found_const_table_map);
//eliminate_tables(join, &const_count, &found_const_table_map);
//:psergey-todo
/* Calc how many (possible) matched records in each table */
@ -16517,7 +16524,7 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
quick_type= -1;
//psergey-todo:
/* Don't show eliminated tables */
if (table->map & join->eliminated_tables)
{
used_tables|=table->map;

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