diff options
Diffstat (limited to 'statement.c')
| -rw-r--r-- | statement.c | 44 |
1 files changed, 33 insertions, 11 deletions
diff --git a/statement.c b/statement.c index 7af103f..ad98223 100644 --- a/statement.c +++ b/statement.c @@ -142,6 +142,14 @@ static const struct ,{ STMT_TYPE_EXPLAIN, "EXPLAIN" } + + /* + * Special-commands that cannot be run in a transaction block. This isn't + * as granular as it could be. VACUUM can never be run in a transaction + * block, but some variants of REINDEX and CLUSTER can be. CHECKPOINT + * doesn't throw an error if you do, but it cannot be rolled back so + * there's no point in beginning a new transaction for it. + */ ,{ STMT_TYPE_SPECIAL, "VACUUM" } @@ -154,6 +162,7 @@ static const struct ,{ STMT_TYPE_SPECIAL, "CHECKPOINT" } + ,{ STMT_TYPE_WITH, "WITH" } @@ -1897,15 +1906,22 @@ SC_execute(StatementClass *self) /* || SC_is_with_hold(self) thiw would lose the performance */ )) issue_begin = FALSE; - else + else if (self->statement_type == STMT_TYPE_SPECIAL) { - switch (self->statement_type) - { - case STMT_TYPE_START: - case STMT_TYPE_SPECIAL: - issue_begin = FALSE; - break; - } + /* + * Some utility commands like VACUUM cannot be run in a transaction + * block, so don't begin one even if auto-commit mode is disabled. + * + * An application should never issue an explicit BEGIN when + * auto-commit mode is disabled (probably not even when it's enabled, + * actually). We used to also suppress the implicit BEGIN when the + * statement was of STMT_TYPE_START type, ie. if the application + * issued an explicit BEGIN, but that actually seems like a bad idea. + * First of all, if you issue a BEGIN twice the backend will give a + * warning which can be helpful to spot mistakes in the application + * (because it shouldn't be doing that). + */ + issue_begin = FALSE; } if (issue_begin) { @@ -2465,10 +2481,16 @@ RequestStart(StatementClass *stmt, ConnectionClass *conn, const char *func) SC_set_error(stmt, STMT_INTERNAL_ERROR, emsg, func); return FALSE; } - if (!CC_is_in_trans(conn) && CC_loves_visible_trans(conn)) + + /* + * In auto-commit mode, begin a new transaction implicitly if no + * transaction is in progress yet. However, some special statements like + * VACUUM and CLUSTER cannot be run in a transaction block. + */ + if (!CC_is_in_trans(conn) && CC_loves_visible_trans(conn) && + stmt->statement_type != STMT_TYPE_SPECIAL) { - if (ret = CC_begin(conn), !ret) - return ret; + ret = CC_begin(conn); } return ret; } |