British English spelling 'behaviour'.

@cindex ANSI mode, running

If you start @code{mysqld} with the @code{--ansi} option, the following

behavior of MySQL Server changes:

behaviour of MySQL Server changes:

@itemize @bullet

@item

@item

If you try to store @code{NULL} into a column that doesn't take

@code{NULL} values, MySQL Server will store 0 or @code{''} (empty

string) in it instead. (This behavior can, however, be changed with the

string) in it instead. (This behaviour can, however, be changed with the

-DDONT_USE_DEFAULT_FIELDS compile option.)

@item

@table @code

@item MySQL Server

Strips all spaces at the end of @code{CHAR} and @code{VARCHAR}

columns. Use a @code{TEXT} column if this behavior is not desired.

columns. Use a @code{TEXT} column if this behaviour is not desired.

@item mSQL

Retains trailing space.

@end table

@table @code

@item MySQL Server

MySQL correctly prioritises everything (@code{AND} is evaluated

before @code{OR}). To get @code{mSQL} behavior in MySQL Server, use

before @code{OR}). To get @code{mSQL} behaviour in MySQL Server, use

parentheses (as shown in an example later in this section).

@item mSQL

Evaluates everything from left to right. This means that some logical

@item

By default, @code{configure} picks @code{c++} as the compiler name and

GNU @code{c++} links with @code{-lg++}.  If you are using @code{gcc},

that behavior can cause problems during configuration such as this:

that behaviour can cause problems during configuration such as this:

@cindex C++ compiler cannot create executables

@example

arguments is a binary string. Otherwise they are case-insensitive.

@item

@code{STRCMP()} now uses the current character set when doing comparisons,

which means that the default comparison behavior now is case-insensitive.

which means that the default comparison behaviour now is case-insensitive.

@item

@code{HEX(string)} now returns the characters in string converted to

hexadecimal.  If you want to convert a number to hexadecimal, you should

@item

@code{LIKE} now compares strings using the same character comparison rules

as @code{=}.  If you require the old behavior, you can compile

as @code{=}.  If you require the old behaviour, you can compile

MySQL with the @code{CXXFLAGS=-DLIKE_CMP_TOUPPER} flag.

@item

if you ask it to map out an address already in use, zeroing out the data

on the entire page, instead of returning an error.  So, the safety of

@code{mysqld} or any other threaded application depends on the "gentleman"

behavior of the code that creates threads.  The user must take measures to

behaviour of the code that creates threads.  The user must take measures to

make sure the number of running threads at any time is sufficiently low for

thread stacks to stay away from the global heap.  With @code{mysqld}, you

should enforce this "gentleman" behavior by setting a reasonable value for

should enforce this "gentleman" behaviour by setting a reasonable value for

the @code{max_connections} variable.

If you build MySQL yourself and do not want to mess with patching

you link MySQL against unmodified @code{LinuxThreads},

removing processors from the machine improves MySQL performance

in many cases.  We have made a patch available for @code{glibc 2.1.3}

to correct this behavior

to correct this behaviour

(@uref{http://www.mysql.com/Downloads/Linux/linuxthreads-2.1-patch}).

With @code{glibc-2.2.2}

that under some conditions, the current mutex code in @code{glibc-2.2.2}

overspins, which hurts MySQL performance. The chance of this

condition can be reduced by renicing @code{mysqld} process to the highest

priority. We have also been able to correct the overspin behavior with

priority. We have also been able to correct the overspin behaviour with

a patch, available at

@uref{http://www.mysql.com/Downloads/Linux/linuxthreads-2.2.2.patch}.

It combines the correction of overspin, maximum number of

@uref{http://ftp.support.compaq.com/public/unix/}.

On OSF/1 V4.0D and compiler "DEC C V5.6-071 on Digital Unix V4.0 (Rev. 878)"

the compiler had some strange behavior (undefined @code{asm} symbols).

the compiler had some strange behaviour (undefined @code{asm} symbols).

@code{/bin/ld} also appears to be broken (problems with @code{_exit

undefined} errors occuring while linking @code{mysqld}).  On this system, we

have managed to compile MySQL with the following @code{configure}

Using this option will cause most temporary files created to use a small

set of names, rather than a unique name for each new file. This is to

work around a problem in the Linux kernel dealing with creating a bunch

of new files with different names. With the old behavior, Linux seems to

of new files with different names. With the old behaviour, Linux seems to

'leak' memory, as it's being allocated to the directory entry cache

instead of the disk cache.

@item

Use passwords for all MySQL users. Remember that anyone can log in

as any other person as simply as @code{mysql -u other_user db_name} if

@code{other_user} has no password.  It is common behavior with client/server

@code{other_user} has no password.  It is common behaviour with client/server

applications that the client may specify any user name.  You can change the

password of all users by editing the @code{mysql_install_db} script before

you run it, or only the password for the MySQL @code{root} user like

comes to what databases and tables you want to choose.

@code{mysqlcheck} does have a special feature compared to the other

clients; the default behavior, checking tables (-c), can be changed by

clients; the default behaviour, checking tables (-c), can be changed by

renaming the binary. So if you want to have a tool that repairs tables

by default, you should just copy @code{mysqlcheck} to your harddrive

with a new name, @code{mysqlrepair}, or alternatively make a symbolic

@code{mysqlrepair}. If you invoke @code{mysqlrepair} now, it will repair

tables by default.

The names that you can use to change @code{mysqlcheck} default behavior

The names that you can use to change @code{mysqlcheck} default behaviour

are here:

@example

As you can see in these results, all databases have some weak points. That

is, they have different design compromises that lead to different

behavior.

behaviour.

If you strive for database independence, you need to get a good feeling

for each SQL server's bottlenecks. MySQL is very fast in

        -> 2

@end example

Note that the behavior of @code{ROUND()} when the argument

Note that the behaviour of @code{ROUND()} when the argument

is half way between two integers depends on the C library

implementation.  Some round to the nearest even number,

always up, always down, or always toward zero.  If you need

returns @code{NULL}.

@code{ENCRYPT()} ignores all but the first 8 characters of @code{str}, at

least on some systems.  This will be determined by the behavior of the

least on some systems.  This will be determined by the behaviour of the

underlying @code{crypt()} system call.

@findex ENCODE()

If you load data from a local file using the @code{LOCAL} keyword, the server

has no way to stop transmission of the file in the middle of the operation,

so the default behavior is the same as if @code{IGNORE} is specified.

so the default behaviour is the same as if @code{IGNORE} is specified.

If you use @code{LOAD DATA INFILE} on an empty @code{MyISAM} table,

all non-unique indexes are created in a separate batch (like in @code{REPAIR}).

of MySQL does not support @code{BDB} tables, the table will be created

as @code{MyISAM} instead.

The other table options are used to optimise the behavior of the

The other table options are used to optimise the behaviour of the

table. In most cases, you don't have to specify any of them.

The options work for all table types, if not otherwise indicated:

Sets the transaction isolation level for the global, whole session or

the next transaction.

The default behavior is to set the isolation level for the next (not

The default behaviour is to set the isolation level for the next (not

started) transaction.  If you use the @code{GLOBAL} keyword, the statement

sets the default transaction level globally for all new connections

created from that point on.  You will need the @code{SUPER}

The search for the word @code{MySQL} produces no results in the above

example, because that word is present in more than half the rows.  As such,

it is effectively treated as a stopword (that is, a word with zero semantic

value).  This is the most desirable behavior -- a natural language query

value).  This is the most desirable behaviour -- a natural language query

should not return every second row from a 1GB table.

A word that matches half of rows in a table is less likely to locate relevant

Unfortunately, full-text search has few user-tunable parameters yet,

although adding some is very high on the TODO. If you have a

MySQL source distribution (@pxref{Installing source}), you can

exert more control over full-text searching behavior.

exert more control over full-text searching behaviour.

Note that full-text search was carefully tuned for the best searching

effectiveness.  Modifying the default behavior will, in most cases,

effectiveness.  Modifying the default behaviour will, in most cases,

only make the search results worse.  Do not alter the MySQL sources

unless you know what you are doing!

will make @code{AUTO_INCREMENT} columns faster (at least 10%) and old

numbers will not be reused as with the old @code{ISAM}. Note that when an

@code{AUTO_INCREMENT} is defined on the end of a multi-part-key the old

behavior is still present.

behaviour is still present.

@item

When inserted in sorted order (as when you are using an @code{AUTO_INCREMENT}

column) the key tree will be split so that the high node only contains one

system resources than @code{ISAM}, but will need more CPU time when inserting

data into a compressed index.

The following options to @code{mysqld} can be used to change the behavior of

The following options to @code{mysqld} can be used to change the behaviour of

@code{MyISAM} tables. @xref{SHOW VARIABLES}.

@multitable @columnfractions .40 .60

gaps in the number sequence if you roll back transactions which have

got numbers from the counter.

The behavior of auto-increment is not defined if a user gives a negative

The behaviour of auto-increment is not defined if a user gives a negative

value to the column or if the value becomes bigger than the maximum

integer that can be stored in the specified integer type.

committed until you execute @code{COMMIT} (or decide to @code{ROLLBACK}

the changes).

The following options to @code{mysqld} can be used to change the behavior of

The following options to @code{mysqld} can be used to change the behaviour of

BDB tables:

@multitable @columnfractions .25 .55

@subsubheading Description

Can be used to set extra connect options and affect behavior for a connection.

Can be used to set extra connect options and affect behaviour for a connection.

This function may be called multiple times to set several options.

@code{mysql_options()} should be called after @code{mysql_init()} and before

@tindex Environment variable, UMASK

then the environment variable @code{UMASK} might be set incorrectly when

@code{mysqld} starts up.  The default umask value is @code{0660}. You can

change this behavior by starting @code{safe_mysqld} as follows:

change this behaviour by starting @code{safe_mysqld} as follows:

@example

shell> UMASK=384  # = 600 in octal

@tindex UMASK_DIR environment variable

@tindex Environment variable, UMASK_DIR

By default MySQL will create database and @code{RAID}

directories with permission type 0700.  You can modify this behavior by

directories with permission type 0700.  You can modify this behaviour by

setting the @code{UMASK_DIR} variable. If you set this, new

directories are created with the combined @code{UMASK} and

@code{UMASK_DIR}. For example, if you want to give group access to

New character set @code{latin_de} which provides correct German sorting.

@item

@code{STRCMP()} now uses the current character set when doing comparisons,

which means that the default comparison behavior now is case-insensitive.

which means that the default comparison behaviour now is case-insensitive.

@item

@code{TRUNCATE TABLE} and @code{DELETE FROM tbl_name} are now separate

functions. One bonus is that @code{DELETE FROM tbl_name} now returns

will cause most temporary files created to use a small set of names,

rather than a unique name for each new file.  This is to work around a

problem in the Linux kernel dealing with creating a bunch of new files

with different names.  With the old behavior, Linux seems to "leak"

with different names.  With the old behaviour, Linux seems to "leak"

memory, as it's being allocated to the directory entry cache instead of

the disk cache.

@end itemize

Updated @code{mysqlhotcopy} to use the new @code{FLUSH TABLES table_list}

syntax. Only tables which are being backed up are flushed now.

@item

Changed behavior of @code{--enable-thread-safe-client} so

Changed behaviour of @code{--enable-thread-safe-client} so

that both non-threaded (@code{-lmysqlclient}) and threaded

(@code{-lmysqlclient_r}) libraries are built.  Users who linked

against a threaded @code{-lmysqlclient} will need to link against

or @code{IS NOT NULL} to test whether a value is @code{NULL}.

(This is according to ANSI SQL but may break

old applications that are ported from @code{mSQL}.)

You can get the old behavior by compiling with @code{-DmSQL_COMPLIANT}.

You can get the old behaviour by compiling with @code{-DmSQL_COMPLIANT}.

@item

Fixed bug that core dumped when using many @code{LEFT OUTER JOIN} clauses.

@item

when encountering ASCII 0, tab, newline or @code{'\'} while writing

tab-separated output.

This is to allow printing of binary data in a portable format.

To get the old behavior, use @code{-r} (or @code{--raw}).

To get the old behaviour, use @code{-r} (or @code{--raw}).

@item

Added german error messages (60 of 80 error messages translated).

@item

variables.

In many cases it's preferable to use a configure file instead of environment

variables to modify the behavior of MySQL. @xref{Option files}.

variables to modify the behaviour of MySQL. @xref{Option files}.

@tindex CCX environment variable

@tindex Environment variable, CCX