Commit 94d2e27d authored by unknown's avatar unknown

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


Docs/manual.texi:
  Auto merged
parents b616a107 64603d9b
mwagner@evoq.mwagner.org monty@tik.mysql.fi
tim@threads.polyesthetic.msg
tim@work.mysql.com
heikki@donna.mysql.fi
paul@central.snake.net
monty@donna.mysql.fi
...@@ -10370,7 +10370,7 @@ feature). ...@@ -10370,7 +10370,7 @@ feature).
Ignore the @code{delay_key_write} option for all tables. Ignore the @code{delay_key_write} option for all tables.
@xref{Server parameters}. @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 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 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 server to start using the grant tables again by executing @code{mysqladmin
...@@ -35350,12 +35350,20 @@ To add a new native @strong{MySQL} function, follow these steps: ...@@ -35350,12 +35350,20 @@ To add a new native @strong{MySQL} function, follow these steps:
Add one line to @file{lex.h} that defines the function name in the Add one line to @file{lex.h} that defines the function name in the
@code{sql_functions[]} array. @code{sql_functions[]} array.
@item @item
Add two lines to @file{sql_yacc.yy}. One indicates the preprocessor If the function prototype is simple (just takes zero, one, two or three
symbol that @code{yacc} should define (this should be added at the arguments), you should in lex.h specify SYM(FUNC_ARG#) (where # is the
beginning of the file). Then define the function parameters and add an number of arguments) as the second argument in the
``item'' with these parameters to the @code{simple_expr} parsing rule. @code{sql_functions[]} array and add a function that creates a function
For an example, check all occurrences of @code{SOUNDEX} in object in @file{item_create.cc}. Take a look at @code{"ABS"} and
@file{sql_yacc.yy} to see how this is done. @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 @item
In @file{item_func.h}, declare a class inheriting from @code{Item_num_func} or 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 @code{Item_str_func}, depending on whether your function returns a number or a
...@@ -35368,28 +35376,45 @@ double Item_func_newname::val() ...@@ -35368,28 +35376,45 @@ double Item_func_newname::val()
longlong Item_func_newname::val_int() longlong Item_func_newname::val_int()
String *Item_func_newname::Str(String *str) String *Item_func_newname::Str(String *str)
@end example @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 @item
You should probably also define the following function: You should probably also define the following object function:
@example @example
void Item_func_newname::fix_length_and_dec() void Item_func_newname::fix_length_and_dec()
@end example @end example
This function should at least calculate @code{max_length} based on the This function should at least calculate @code{max_length} based on the
given arguments. @code{max_length} is the maximum number of characters given arguments. @code{max_length} is the maximum number of characters
the function may return. This function should also set @code{maybe_null = 0} the function may return. This function should also set @code{maybe_null
if the main function can't return a @code{NULL} value. The function can check = 0} if the main function can't return a @code{NULL} value. The
if any of the function arguments can return @code{NULL} by checking the function can check if any of the function arguments can return
arguments @code{maybe_null} variable. @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 @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 @itemize @bullet
@item @item
The @code{String *str} argument provides a string The @code{String *str} argument provides a string buffer that may be
buffer that may be used to hold the result. used to hold the result. (For more information about the @code{String} type,
take a look at the @file{sql_string.h} file.)
@item @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 @item
All current string functions try to avoid allocating any memory unless All current string functions try to avoid allocating any memory unless
absolutely necessary! absolutely necessary!
encrypt('foo', 'ff') length(encrypt('foo', 'ff')) <> 0
ffTU0fyIP09Z. 1
select encrypt('foo', 'ff');
select length(encrypt('foo', 'ff')) <> 0;
...@@ -449,7 +449,7 @@ int thr_lock(THR_LOCK_DATA *data,enum thr_lock_type lock_type) ...@@ -449,7 +449,7 @@ int thr_lock(THR_LOCK_DATA *data,enum thr_lock_type lock_type)
check_locks(lock,"read lock with old write lock",0); check_locks(lock,"read lock with old write lock",0);
if (lock->get_status) if (lock->get_status)
(*lock->get_status)(data->status_param); (*lock->get_status)(data->status_param);
++locks_immediate; statistic_increment(locks_immediate,&THR_LOCK_lock);
goto end; goto end;
} }
if (lock->write.data->type == TL_WRITE_ONLY) if (lock->write.data->type == TL_WRITE_ONLY)
...@@ -473,7 +473,7 @@ int thr_lock(THR_LOCK_DATA *data,enum thr_lock_type lock_type) ...@@ -473,7 +473,7 @@ int thr_lock(THR_LOCK_DATA *data,enum thr_lock_type lock_type)
if ((int) lock_type == (int) TL_READ_NO_INSERT) if ((int) lock_type == (int) TL_READ_NO_INSERT)
lock->read_no_write_count++; lock->read_no_write_count++;
check_locks(lock,"read lock with no write locks",0); check_locks(lock,"read lock with no write locks",0);
++locks_immediate; statistic_increment(locks_immediate,&THR_LOCK_lock);
goto end; goto end;
} }
/* Can't get lock yet; Wait for it */ /* Can't get lock yet; Wait for it */
...@@ -505,7 +505,7 @@ int thr_lock(THR_LOCK_DATA *data,enum thr_lock_type lock_type) ...@@ -505,7 +505,7 @@ int thr_lock(THR_LOCK_DATA *data,enum thr_lock_type lock_type)
data->cond=get_cond(); data->cond=get_cond();
if (lock->get_status) if (lock->get_status)
(*lock->get_status)(data->status_param); (*lock->get_status)(data->status_param);
++locks_immediate; statistic_increment(locks_immediate,&THR_LOCK_lock);
goto end; goto end;
} }
} }
...@@ -540,7 +540,7 @@ int thr_lock(THR_LOCK_DATA *data,enum thr_lock_type lock_type) ...@@ -540,7 +540,7 @@ int thr_lock(THR_LOCK_DATA *data,enum thr_lock_type lock_type)
check_locks(lock,"second write lock",0); check_locks(lock,"second write lock",0);
if (data->lock->get_status) if (data->lock->get_status)
(*data->lock->get_status)(data->status_param); (*data->lock->get_status)(data->status_param);
++locks_immediate; statistic_increment(locks_immediate,&THR_LOCK_lock);
goto end; goto end;
} }
DBUG_PRINT("lock",("write locked by thread: %ld", DBUG_PRINT("lock",("write locked by thread: %ld",
...@@ -566,7 +566,7 @@ int thr_lock(THR_LOCK_DATA *data,enum thr_lock_type lock_type) ...@@ -566,7 +566,7 @@ int thr_lock(THR_LOCK_DATA *data,enum thr_lock_type lock_type)
if (data->lock->get_status) if (data->lock->get_status)
(*data->lock->get_status)(data->status_param); (*data->lock->get_status)(data->status_param);
check_locks(lock,"only write lock",0); check_locks(lock,"only write lock",0);
++locks_immediate; statistic_increment(locks_immediate,&THR_LOCK_lock);
goto end; goto end;
} }
} }
......
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