Merge work:/my/mysql into tik.mysql.fi:/home/my/mysql

mwagner@evoq.mwagner.org

tim@threads.polyesthetic.msg

tim@work.mysql.com

heikki@donna.mysql.fi

paul@central.snake.net

monty@donna.mysql.fi

monty@tik.mysql.fi

Ignore the @code{delay_key_write} option for all tables.

@xref{Server parameters}.

@item -Sg, --skip-grant-tables

@item --skip-grant-tables

This option causes the server not to use the privilege system at all.  This

gives everyone @emph{full access} to all databases!  (You can tell a running

server to start using the grant tables again by executing @code{mysqladmin

Add one line to @file{lex.h} that defines the function name in the

@code{sql_functions[]} array.

@item

Add two lines to @file{sql_yacc.yy}. One indicates the preprocessor

symbol that @code{yacc} should define (this should be added at the

beginning of the file). Then define the function parameters and add an

``item'' with these parameters to the @code{simple_expr} parsing rule.

For an example, check all occurrences of @code{SOUNDEX} in

@file{sql_yacc.yy} to see how this is done.

If the function prototype is simple (just takes zero, one, two or three

arguments), you should in lex.h specify SYM(FUNC_ARG#) (where # is the

number of arguments) as the second argument in the

@code{sql_functions[]} array and add a function that creates a function

object in @file{item_create.cc}.  Take a look at @code{"ABS"} and

@code{create_funcs_abs()} for an example of this.

If the function prototype is complicated (for example takes a variable number

of arguments), you should add two lines to @file{sql_yacc.yy}. One

indicates the preprocessor symbol that @code{yacc} should define (this

should be added at the beginning of the file). Then define the function

parameters and add an ``item'' with these parameters to the

@code{simple_expr} parsing rule.  For an example, check all occurrences

of @code{ATAN} in @file{sql_yacc.yy} to see how this is done.

@item

In @file{item_func.h}, declare a class inheriting from @code{Item_num_func} or

@code{Item_str_func}, depending on whether your function returns a number or a

longlong Item_func_newname::val_int()

String  *Item_func_newname::Str(String *str)

@end example

If you inherit your object from any of the standard items (like

@code{Item_num_func} you probably only have to define one of the above

functions and let the parent object take care of the other functions.

For example, the @code{Item_str_func} class defines a @code{val()} function

that executes @code{atof()} on the value returned by @code{::str()}.

@item

You should probably also define the following function:

You should probably also define the following object function:

@example

void Item_func_newname::fix_length_and_dec()

@end example

This function should at least calculate @code{max_length} based on the

given arguments. @code{max_length} is the maximum number of characters

the function may return.  This function should also set @code{maybe_null = 0}

if the main function can't return a @code{NULL} value.  The function can check

if any of the function arguments can return @code{NULL} by checking the

arguments @code{maybe_null} variable.

the function may return.  This function should also set @code{maybe_null

= 0} if the main function can't return a @code{NULL} value.  The

function can check if any of the function arguments can return

@code{NULL} by checking the arguments @code{maybe_null} variable. You

can take a look at @code{Item_func_mod::fix_length_and_dec} for a

typical example of how to do this.

@end enumerate

All functions must be thread safe.

All functions must be thread safe (In other words, don't use any global or

static variables in the functions without protecting them with mutexes).

If you want to return @code{NULL}, from @code{::val()}, @code{::val_int()}

or @code{::str()} you should set @code{null_value} to 1 and return 0.

For @code{::str()} object functions, there are some additional

considerations to be aware of:

For string functions, there are some additional considerations to be aware of:

@itemize @bullet

@item

The @code{String *str} argument provides a string

buffer that may be used to hold the result.

The @code{String *str} argument provides a string buffer that may be

used to hold the result. (For more information about the @code{String} type,

take a look at the @file{sql_string.h} file.)

@item

The function should return the string that holds the result.

The @code{::str()} function should return the string that holds the result or

@code{(char*) 0} if the result is @code{NULL}.

@item

All current string functions try to avoid allocating any memory unless

absolutely necessary!

encrypt('foo', 'ff')

ffTU0fyIP09Z.

length(encrypt('foo', 'ff')) <> 0

1

select encrypt('foo', 'ff');

select length(encrypt('foo', 'ff')) <> 0;

	check_locks(lock,"read lock with old write lock",0);

	if (lock->get_status)

	  (*lock->get_status)(data->status_param);

	++locks_immediate;

	statistic_increment(locks_immediate,&THR_LOCK_lock);

	goto end;

      }

      if (lock->write.data->type == TL_WRITE_ONLY)

      if ((int) lock_type == (int) TL_READ_NO_INSERT)

	lock->read_no_write_count++;

      check_locks(lock,"read lock with no write locks",0);

      ++locks_immediate;

      statistic_increment(locks_immediate,&THR_LOCK_lock);

      goto end;

    }

    /* Can't get lock yet;  Wait for it */

	data->cond=get_cond();

	if (lock->get_status)

	  (*lock->get_status)(data->status_param);

	++locks_immediate;

	statistic_increment(locks_immediate,&THR_LOCK_lock);

	goto end;

      }

    }

	check_locks(lock,"second write lock",0);

	if (data->lock->get_status)

	  (*data->lock->get_status)(data->status_param);

	++locks_immediate;

	statistic_increment(locks_immediate,&THR_LOCK_lock);

	goto end;

      }

      DBUG_PRINT("lock",("write locked by thread: %ld",

	  if (data->lock->get_status)

	    (*data->lock->get_status)(data->status_param);

	  check_locks(lock,"only write lock",0);

	  ++locks_immediate;

	  statistic_increment(locks_immediate,&THR_LOCK_lock);

	  goto end;

	}

      }