PostgreSQL �̎��s�v��� Tid Scan
PostgreSQL �ɂ� ORACLE �� ROWID �̂悤�� �s��f�����w�肷�邽�߂̗� ctid ������܂��B
db=# SELECT ctid, * FROM test.table1; ctid | f1 | f2 ----------+-------+--------------- (0,1) | A143H | test@test.com (0,2) | A393G | test@test.com (0,3) | A380E | test@test.com (0,4) | A147K | test@test.com
ctid �́A�s�o�[�W�����̕����I�ʒu�Ȃ̂� �s���X�V������AVACUUM FULL �ŕς���Ă��܂��܂��B
�����A���� ctid ���g�p����Ƃ��Ȃ葁���s���擾�ł��܂��B ���̂Ƃ��̎��s�v��ɏo�Ă��鉉�Z�q�� Tid Scan �Ȃ̂ł��B
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db=# EXPLAIN db-# SELECT * FROM test.table1 WHERE ctid = '(0,2)'; QUERY PLAN ------------------------------------------------------------ Tid Scan on table1 (cost=0.00..4.01 rows=1 width=218) TID Cond: (ctid = '(0,2)'::tid)
Tid Scan �Əo�܂����B
PRIMARY KEY �Ō��������ꍇ�̎��s�v����擾���Ă݂܂��B
db=# EXPLAIN db-# SELECT * FROM test.table1 WHERE field1 = 1; QUERY PLAN --------------------------------------------------------------------------- Index Scan using table1_pkey on table1 (cost=0.00..8.27 rows=1 width=50) Index Cond: ((field1)::text = '1'::text)
Index Scan ������� Tid Scan �̕����R�X�g���������ł��ˁB
