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1bd681c8b3
This is a complete rewrite of DROP TABLE, also as part of other DDL, such as ALTER TABLE, CREATE TABLE...SELECT, TRUNCATE TABLE. The background DROP TABLE queue hack is removed. If a transaction needs to drop and create a table by the same name (like TRUNCATE TABLE does), it must first rename the table to an internal #sql-ib name. No committed version of the data dictionary will include any #sql-ib tables, because whenever a transaction renames a table to a #sql-ib name, it will also drop that table. Either the rename will be rolled back, or the drop will be committed. Data files will be unlinked after the transaction has been committed and a FILE_RENAME record has been durably written. The file will actually be deleted when the detached file handle returned by fil_delete_tablespace() will be closed, after the latches have been released. It is possible that a purge of the delete of the SYS_INDEXES record for the clustered index will execute fil_delete_tablespace() concurrently with the DDL transaction. In that case, the thread that arrives later will wait for the other thread to finish. HTON_TRUNCATE_REQUIRES_EXCLUSIVE_USE: A new handler flag. ha_innobase::truncate() now requires that all other references to the table be released in advance. This was implemented by Monty. ha_innobase::delete_table(): If CREATE TABLE..SELECT is detected, we will "hijack" the current transaction, drop the table in the current transaction and commit the current transaction. This essentially fixes MDEV-21602. There is a FIXME comment about making the check less failure-prone. ha_innobase::truncate(), ha_innobase::delete_table(): Implement a fast path for temporary tables. We will no longer allow temporary tables to use the adaptive hash index. dict_table_t::mdl_name: The original table name for the purpose of acquiring MDL in purge, to prevent a race condition between a DDL transaction that is dropping a table, and purge processing undo log records of DML that had executed before the DDL operation. For #sql-backup- tables during ALTER TABLE...ALGORITHM=COPY, the dict_table_t::mdl_name will differ from dict_table_t::name. dict_table_t::parse_name(): Use mdl_name instead of name. dict_table_rename_in_cache(): Update mdl_name. For the internal FTS_ tables of FULLTEXT INDEX, purge would acquire MDL on the FTS_ table name, but not on the main table, and therefore it would be able to run concurrently with a DDL transaction that is dropping the table. Previously, the DROP TABLE queue hack prevented a race between purge and DDL. For now, we introduce purge_sys.stop_FTS() to prevent purge from opening any table, while a DDL transaction that may drop FTS_ tables is in progress. The function fts_lock_table(), which will be invoked before the dictionary is locked, will wait for purge to release any table handles. trx_t::drop_table_statistics(): Drop statistics for the table. This replaces dict_stats_drop_index(). We will drop or rename persistent statistics atomically as part of DDL transactions. On lock conflict for dropping statistics, we will fail instantly with DB_LOCK_WAIT_TIMEOUT, because we will be holding the exclusive data dictionary latch. trx_t::commit_cleanup(): Separated from trx_t::commit_in_memory(). Relax an assertion around fts_commit() and allow DB_LOCK_WAIT_TIMEOUT in addition to DB_DUPLICATE_KEY. The call to fts_commit() is entirely misplaced here and may obviously break the consistency of transactions that affect FULLTEXT INDEX. It needs to be fixed separately. dict_table_t::n_foreign_key_checks_running: Remove (MDEV-21175). The counter was a work-around for missing meta-data locking (MDL) on the SQL layer, and not really needed in MariaDB. ER_TABLE_IN_FK_CHECK: Replaced with ER_UNUSED_28. HA_ERR_TABLE_IN_FK_CHECK: Remove. row_ins_check_foreign_constraints(): Do not acquire dict_sys.latch either. The SQL-layer MDL will protect us. This was reviewed by Thirunarayanan Balathandayuthapani and tested by Matthias Leich.
40 lines
891 B
Plaintext
40 lines
891 B
Plaintext
CREATE TABLE t1 (a INT) ENGINE=InnoDB;
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INSERT INTO t1 VALUES (1);
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connect con1,localhost,root;
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XA START 'x';
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UPDATE t1 set a=2;
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XA END 'x';
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XA PREPARE 'x';
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connect con2,localhost,root;
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CREATE TABLE t2 (a INT) ENGINE=InnoDB;
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XA START 'y';
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INSERT INTO t2 VALUES (1);
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XA END 'y';
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XA PREPARE 'y';
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connection default;
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# restart: --innodb-force-recovery=2
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disconnect con1;
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disconnect con2;
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connect con1,localhost,root;
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SELECT * FROM t1 LOCK IN SHARE MODE;
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connection default;
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SET innodb_lock_wait_timeout=1;
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DROP TABLE t2;
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ERROR HY000: Lock wait timeout exceeded; try restarting transaction
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disconnect con1;
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SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED;
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SELECT * FROM t1;
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a
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2
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XA ROLLBACK 'x';
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SELECT * FROM t1;
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a
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1
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DROP TABLE t1;
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DROP TABLE t2;
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ERROR HY000: Lock wait timeout exceeded; try restarting transaction
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XA ROLLBACK 'y';
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DROP TABLE t2;
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SET GLOBAL innodb_fast_shutdown=0;
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# restart
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