F.2. auto_explain

F.2.1. ����ѥ�᡼��

auto_explain��ư������椹�뤤���Ĥ��ι����ѥ�᡼����¸�ߤ��ޤ����ǥե���Ȥ�ư��ϲ��⤷�ʤ����ȤʤΤǡ��ʤ�餫�η�̤�˾��ΤǤ���о��ʤ��Ȥ�auto_explain.log_min_duration�����ꤷ�ʤ���Фʤ�ʤ����Ȥ����դ��Ƥ���������

�����ѥ�᡼����postgresql.conf�ե���������ꤹ�뤿��ˤϡ�custom_variable_classes��auto_explain���ɲä���ɬ�פ�����ޤ���ŵ��Ū�ʻ���ˡ�ϰʲ��Τ褦�ˤʤ�ޤ���

# postgresql.conf
shared_preload_libraries = 'auto_explain'

custom_variable_classes = 'auto_explain'
auto_explain.log_min_duration = '3s'
  

F.2.2. ��

  postgres=# LOAD 'auto_explain';
  postgres=# SET auto_explain.log_min_duration = 0;
  postgres=# SELECT count(*)
               FROM pg_class, pg_index
              WHERE oid = indrelid AND indisunique;
  

����ˤ�ꡢ�ʲ��Τ褦�ʥ������Ϥ���������ޤ���

  LOG:  duration: 0.986 ms  plan:
          Aggregate  (cost=14.90..14.91 rows=1 width=0)
            ->  Hash Join  (cost=3.91..14.70 rows=81 width=0)
                  Hash Cond: (pg_class.oid = pg_index.indrelid)
                  ->  Seq Scan on pg_class  (cost=0.00..8.27 rows=227 width=4)
                  ->  Hash  (cost=2.90..2.90 rows=81 width=4)
                        ->  Seq Scan on pg_index  (cost=0.00..2.90 rows=81 width=4)
                              Filter: indisunique
  STATEMENT:  SELECT count(*)
            FROM pg_class, pg_index
           WHERE oid = indrelid AND indisunique;
  

F.2.3. ���

�ij� ��͵ <itagaki.takahiro.at.oss.ntt.co.jp>