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| -rw-r--r-- | Docs/manual.texi | 38 |
1 files changed, 25 insertions, 13 deletions
diff --git a/Docs/manual.texi b/Docs/manual.texi index 2cb5569ce6c..c060c0e4d21 100644 --- a/Docs/manual.texi +++ b/Docs/manual.texi @@ -17384,7 +17384,7 @@ CHECK TABLE tbl_name[,tbl_name...] [option [option...]] option = QUICK | FAST | MEDIUM | EXTENDED | CHANGED @end example -@code{CHECK TABLE} only works on @code{MyISAM} tables. On +@code{CHECK TABLE} only works on @code{MyISAM} and @code{InnoDB} tables. On @code{MyISAM} tables it's the same thing as running @code{myisamchk -m table_name} on the table. @@ -25842,10 +25842,17 @@ from the data, you should not lose anything by using @code{DELAY_KEY_WRITE}. You can find a discussion about different locking methods in the appendix. @xref{Locking methods}. -All locking in MySQL is deadlock-free. This is managed by always +All locking in MySQL is deadlock-free, except for @code{InnoDB} and +@code{BDB} type tables. +This is managed by always requesting all needed locks at once at the beginning of a query and always locking the tables in the same order. +@code{InnoDB} type tables automatically acquire their row locks and +@code{BDB} type tables +their page locks during the processing of SQL statements, not at the start +of the transaction. + The locking method MySQL uses for @code{WRITE} locks works as follows: @itemize @bullet @@ -25905,16 +25912,18 @@ priority, which might help some applications. The table locking code in MySQL is deadlock free. MySQL uses table locking (instead of row locking or column -locking) on all table types, except @code{BDB} tables, to achieve a very +locking) on all table types, except @code{InnoDB} and @code{BDB} tables, +to achieve a very high lock speed. For large tables, table locking is much better than row locking for most applications, but there are, of course, some pitfalls. For @code{InnoDB} and @code{BDB} tables, MySQL only uses table -locking if you explicitely lock the table with @code{LOCK TABLES} or -execute a command that will modify every row in the table, like -@code{ALTER TABLE}. For these table types we recommend you to not use -@code{LOCK TABLES} at all. +locking if you explicitly lock the table with @code{LOCK TABLES}. +For these table types we recommend you to not use +@code{LOCK TABLES} at all, because @code{InnoDB} uses automatic +row level locking and @code{BDB} uses page level locking to +ensure transaction isolation. In MySQL Version 3.23.7 and above, you can insert rows into @code{MyISAM} tables at the same time other threads are reading from the @@ -35217,8 +35226,8 @@ exist. @code{RESTRICT} and @code{CASCADE} are allowed to make porting easier. For the moment they don't do anything. -@strong{Note}: @code{DROP TABLE} is not transaction-safe and will -automatically commit any active transactions. +@strong{Note}: @code{DROP TABLE} will +automatically commit current active transaction. @node CREATE INDEX, DROP INDEX, DROP TABLE, Data Definition @@ -54935,8 +54944,10 @@ In MySQL, common tags to print (with the @code{d} option) are: @cindex methods, locking Currently MySQL only supports table locking for -@code{ISAM}/@code{MyISAM} and @code{HEAP} tables and page level locking -for @code{BDB} tables. @xref{Internal locking}. With @code{MyISAM} +@code{ISAM}/@code{MyISAM} and @code{HEAP} tables. +@code{InnoDB} tables use row level locking, +and @code{BDB} tables page level locking. @xref{Internal locking}. +With @code{MyISAM} tables one can freely mix @code{INSERT} and @code{SELECT} without locks (@code{Versioning}). @@ -55036,8 +55047,9 @@ a single lock is much faster than updates without locks). Splitting thing to different tables will also helps. If you get speed problems with the table locks in MySQL, you -may be able to solve these to convert some of your tables to @code{BDB} tables. -@xref{BDB}. +may be able to solve these by converting some of your tables to @code{InnoDB} +or @code{BDB} tables. +@xref{InnoDB}. @xref{BDB}. The optimisation section in the manual covers a lot of different aspects of how to tune ones application. @xref{Tips}. |