フリー問題

問題文

Two sessions both insert rows into the same global temporary table and then both query it. What does each session see in the table?

選択肢

1. Each session sees no rows at all, because the definition of such a table is shared while the data is discarded as soon as the insert finishes.
2. The second session fails to insert, because the definition of such a table belongs to the session that created it and cannot be used by anybody else at all.
3. Each session sees its own rows alone, because the definition of such a table is shared while the rows of that table belong to the session that wrote them.
4. Each session sees the rows of both sessions, because the definition of such a table is shared and the data is shared with it in the same way.