Merge paul@work.mysql.com:/home/bk/mysql-4.0

options.  @xref{InnoDB start}.

If you are using BDB (Berkeley DB) tables, you should familiarise

yourself with the different BDB specific startup options.  @xref{BDB start}.

yourself with the different BDB-specific startup options.  @xref{BDB start}.

@node Automatic start,  , Starting server, Post-installation

because configure didn't detect the @code{readlink} system call.)

@item

@code{OPTIMIZE TABLE} now only works for @code{MyISAM} tables.

@code{OPTIMIZE TABLE} now works only for @code{MyISAM} tables.

For other table types, you can use @code{ALTER TABLE} to optimise the table.

During @code{OPTIMIZE TABLE} the table is now locked from other threads.

@end enumerate

Another solution is to sort all rows descending by price and only

get the first row using the MySQL specific @code{LIMIT} clause:

get the first row using the MySQL-specific @code{LIMIT} clause:

@example

SELECT article, dealer, price

Copies to the backup directory the minimum number of table files needed

to restore the table, after flushing any buffered changes to disk. Currently

only works for @code{MyISAM} tables.

works only for @code{MyISAM} tables.

For @code{MyISAM} tables, copies @file{.frm} (definition)  and

@file{.MYD} (data) files. The index file can be rebuilt from those two.

option = QUICK | FAST | MEDIUM | EXTENDED | CHANGED

@end example

@code{CHECK TABLE} only works on @code{MyISAM} and @code{InnoDB} tables. On

@code{CHECK TABLE} works only 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.

REPAIR TABLE tbl_name[,tbl_name...] [QUICK] [EXTENDED] [USE_FRM]

@end example

@code{REPAIR TABLE} only works on @code{MyISAM} tables and is the same

@code{REPAIR TABLE} works only on @code{MyISAM} tables and is the same

as running @code{myisamchk -r table_name} on the table.

Normally you should never have to run this command, but if disaster strikes

If you use @code{EXTENDED} then MySQL will create the index row

by row instead of creating one index at a time with sorting; this may be

better than sorting on fixed-length keys if you have long @code{char()}

keys that compress very good.

better than sorting on fixed-length keys if you have long @code{CHAR}

keys that compress very well.

As of @code{MySQL} 4.0.2 there is a @code{USE_FRM} mode for @code{REPAIR}.

Use it if the @file{.MYI} file is missing or if its header is corrupted.

operations reuse old record positions. You can use @code{OPTIMIZE TABLE} to

reclaim the unused space and to defragment the datafile.

For the moment, @code{OPTIMIZE TABLE} only works on @code{MyISAM} and

For the moment, @code{OPTIMIZE TABLE} works only on @code{MyISAM} and

@code{BDB} tables. For @code{BDB} tables, @code{OPTIMIZE TABLE} is

currently mapped to @code{ANALYZE TABLE}.

@xref{ANALYZE TABLE, , @code{ANALYZE TABLE}}.

You can also use the @code{mysqladmin processlist} and @code{mysqladmin kill}

commands to examine and kill threads.

When you do a @code{KILL}, a thread specific @code{kill flag} is set for

When you do a @code{KILL}, a thread-specific @code{kill flag} is set for

the thread.

In most cases it may take some time for the thread to die as the kill

@item @code{record_rnd_buffer_size}

When reading rows in sorted order after a sort, the rows are read

through this buffer to avoid a disk seeks.  Can improve @code{ORDER BY}

by a lot if set to a high value.  As this is a thread specific variable,

by a lot if set to a high value.  As this is a thread-specific variable,

one should not set this big globally, but just change this when running

some specific big queries.

and connection variables. One can change most of them without having to take

down the server.

There are two kind of system variables: Thread (or connection) specific

There are two kind of system variables: Thread-specific (or

connection-specific)

variables that are unique to the current connection and global variables

that are either used to configure global events or used as initial

variables for a new connection.

that are used to configure global events.

Global variables also are used to set up the initial values of the

corresponding thread-specific variables for new connections.

When mysqld starts all global variables are initialised from command

line arguments and option files.  You can change the used value with the

@code{SET GLOBAL} command. When a new thread is created the thread

specific variables are initialised from the global variables and they

will not change even if one issues a new @code{SET GLOBAL} command.

When @code{mysqld} starts, all global variables are initialised from command

line arguments and option files.  You can change the value with the

@code{SET GLOBAL} command. When a new thread is created, the thread-specific

variables are initialised from the global variables and they

will not change even if you issue a new @code{SET GLOBAL} command.

To set the value for a @code{GLOBAL} variable, you should use one

of the following syntaxes:

When you @strong{retrieve} a variable value with the

@code{@@@@variable_name} syntax and you don't specify @code{GLOBAL} or

@code{SESSION} then MySQL will return the thread specific

@code{SESSION} then MySQL will return the thread-specific

(@code{SESSION}) value if it exists.  If not, MySQL will return the

global value.

The reason for requiring @code{GLOBAL} for setting @code{GLOBAL} only

variables but not for retrieving them is to ensure that we don't later

run into problems if we later would introduce a thread specific variable

with the same name or remove a thread specific variable.  In this case

you could accidently change the state for the whole server and not

run into problems if we later would introduce a thread-specific variable

with the same name or remove a thread-specific variable.  In this case,

you could accidentally change the state for the server as a whole, rather than

just for your own connection.

The following is a full list of all variables that you change and retrieve

@item query_cache_size @tab num @tab GLOBAL

@item query_cache_type @tab enum @tab GLOBAL

@item read_buffer_size @tab num @tab GLOBAL | SESSION

@item read_rnd_buffer_size num @tab GLOBAL | SESSION

@item read_rnd_buffer_size @tab num @tab GLOBAL | SESSION

@item rpl_recovery_rank @tab num @tab GLOBAL

@item safe_show_database @tab bool @tab GLOBAL

@item server_id @tab num @tab GLOBAL

@item identity @tab Alias for last_insert_id (Sybase compatiblity)

@item sql_low_priority_updates @tab Alias for low_priority_updates

@item sql_max_join_size @tab Alias for max_join_size

@item delay_key_write_for_all_tables @tab If this and delay_key_write is set then all new MyISAM tables that are opened will use delayed key writes.

@item delay_key_write_for_all_tables @tab If this and delay_key_write are set, then all new MyISAM tables that are opened will use delayed key writes.

@item version @tab Alias for VERSION() (Sybase (?) compatability)

@end multitable

@subsubheading Description

This function needs to be called for each created thread to initialise

thread specific variables.

thread-specific variables.

This is automatically called by @code{my_init()} and @code{mysql_connect()}.

MySQL database:

When you call @code{mysql_init()} or @code{mysql_connect()}, MySQL will

create a thread specific variable for the thread that is used by the

create a thread-specific variable for the thread that is used by the

debug library (among other things).

If you call a MySQL function, before the thread has

called @code{mysql_init()} or @code{mysql_connect()}, the thread will

not have the necessary thread specific variables in place and you are

not have the necessary thread-specific variables in place and you are

likely to end up with a core dump sooner or later.

The get things to work smoothly you have to do the following:

any MySQL function.

@item

In the thread, call @code{mysql_thread_end()} before calling

@code{pthread_exit()}.  This will free the memory used by MySQL thread

specific variables.

@code{pthread_exit()}.  This will free the memory used by MySQL

thread-specific variables.

@end enumerate

You may get some errors because of undefined symbols when linking your

Put common options in the @code{[server]} section. These will be read by

both MySQL versions.

@item

Put client/server specific options in the @code{[mysqld]} section.

Put client/server-specific options in the @code{[mysqld]} section.

@item

Put embedded MySQL specific options in the @code{[embedded]} section.

Put embedded MySQL-specific options in the @code{[embedded]} section.

@item

Put application specific options in a @code{[ApplicationName_SERVER]}

Put application-specific options in a @code{[ApplicationName_SERVER]}

section.

@end itemize

It's safe to increase this variable as memory is only allocated when

needed; this variable is more a precaution to catch wrong packets

between the client/server and also to ensure that you don't accidently

between the client/server and also to ensure that you don't accidentally

use big packets so that you run out of memory.

If you are using the @code{mysql} client, you may specify a bigger

@item

Fixed a timing bug in @code{DROP DATABASE}

@item

New @code{SET [GLOBAL | SESSION]} syntax to change thread specific and global

New @code{SET [GLOBAL | SESSION]} syntax to change thread-specific and global

server variables at runtime.

@item

Added variable @code{slave_compressed_protocol}.