Linux kernel uses a number of advanced keywords, macros, and extensions to C language. Here is a description of some of these keywords, macros and extensions that I found troublesome to understand and had to investigate a little bit in order to understand them.
I have used kernel versions 2.4.18 or 2.6.0 for this tutorial.
#define MAX_FIELDS 4096 /* Limit in the .frm file */
I should be able to remove this limitation soon. Although if you come anywhere near it, you probably have already lost (and written your own engine).
Baron was just writing about problems with the Debian init scripts. The basic problem boils down to /etc/mysql/debian-start running mysqlcheck on every table.
Kolbe Kolbe and Harrison Fisk pointed this out to me last February, and as a result I re-wrote the debian-start.inc script to only operate on MyISAM tables. Additionally, the default config was changed to turn on the myisam-recover option, so even for the MyISAM tables, all we do is touch the table to get MySQL to recover it if needed. (Which I promise you, you really want if you're modifying MyISAM tables on a production server. Don't do that, really, but that's another issue.) The new process essentiall looks like this:
for table in `select TABLE_NAME from information_schema.TABLES where ENGINE='MyISAM'":
select count(*) into …[Read more]
Baron was just writing about problems with the Debian init scripts. The basic problem boils down to /etc/mysql/debian-start running mysqlcheck on every table.
Kolbe Kolbe and Harrison Fisk pointed this out to me last February, and as a result I re-wrote the debian-start.inc script to only operate on MyISAM tables. Additionally, the default config was changed to turn on the myisam-recover option, so even for the MyISAM tables, all we do is touch the table to get MySQL to recover it if needed. (Which I promise you, you really want if you're modifying MyISAM tables on a production server. Don't do that, really, but that's another issue.) The new process essentiall looks like this:
for table in `select TABLE_NAME from information_schema.TABLES where ENGINE='MyISAM'":
select count(*) into …[Read more]
So what happens if you want to use the mysql functions
AES_ENCRYPT / AES_DECRYPT to handle data encryption, but you
might also need to write a tool that takes the encrypted data and
accesses or updates it outside of the database? This operation
can be hit or miss depending on your library's implementation of
how it handles the encryption key passed to the actual encryption
function. There is no standard on how this is handled.
AES only defines that it accepts an encryption key of
AES_KEY_LENGTH/8 bytes. So for 128 bit encyption you need to give
it a 16 byte key.
In mysql you can do:
AES_ENCRYPT('mykey','here is a string to encrypt');
But we just passed it a 5 character string, where does the 16
byte key come from? This is the part that can differ between
libraries. MySQL takes your string and converts it like
this:
static int my_aes_create_key(KEYINSTANCE *aes_key,
enum …
Baron was just writing about problems with the Debian init scripts. The basic problem boils down to /etc/mysql/debian-start running mysqlcheck on every table.
Kolbe Kolbe and Harrison Fisk pointed this out to me last February, and as a result I re-wrote the debian-start.inc script to only operate on MyISAM tables. Additionally, the default config was changed to turn on the myisam-recover option, so even for the MyISAM tables, all we do is touch the table to get MySQL to recover it if needed. (Which I promise you, you really want if you're modifying MyISAM tables on a production server. Don't do that, really, but that's another issue.) The new process essentiall looks like this:
for table in `select TABLE_NAME from information_schema.TABLES where ENGINE='MyISAM'":
select count(*) into …[Read more]
Microsoft Windows PowerShell command line shell and scripting language helps IT professionals achieve greater control and productivity. Using a new admin-focused scripting language, more than 130 standard command line tools, and consistent syntax and utilities, Windows PowerShell allows IT professionals to more easily control system administration and accelerate automation.
Microsoft Windows PowerShell command line shell and scripting language helps IT professionals achieve greater control and productivity. Using a new admin-focused scripting language, more than 130 standard command line tools, and consistent syntax and utilities, Windows PowerShell allows IT professionals to more easily control system administration and accelerate automation.
Today, I found the function in Innodb which maps Mysql data types
to innodb data types. It is get_innobase_type_from_mysql_type
which is located in the file ha_innodb.cc. The function takes an
input parameter of type Field from mysql classes. This filed is
then analyzed to set an output function paremeter that indicates
whether the field is signed or unsigned and then the return value
of the function is a macro integer code. The codes are defined in
data0type.h as follows:
/*-------------------------------------------*/
/* The 'MAIN TYPE' of a column */
#define DATA_VARCHAR 1
#define DATA_CHAR 2
#define DATA_FIXBINARY 3
#define DATA_BINARY 4
#define DATA_BLOB 5
#define DATA_INT 6
#define DATA_SYS_CHILD 7
#define DATA_SYS 8
#define DATA_FLOAT 9
#define DATA_DOUBLE 10
#define DATA_DECIMAL 11
#define DATA_VARMYSQL 12
#define DATA_MYSQL …
Yes please, schedule this event in your calendar or heck set up
an event in your MySQL 5.1 server ;) (yeah yeah, stupid joke).
I'll be in Boston next week, Wednesday, February 4th, talking to
the MySQL Meetup which will be held at MIT. The topic on hand
will be the MySQL 5.1 Event Scheduler. Please come down,
I'd love to meet you and talk to you, whether it's about the
MySQL Event Scheduler or anything else about MySQL (or PHP or
whatever other knowledge that is hidden in my mind).
Here are the details:
Wednesday February 4th - MySQL Meetup - Conference Room
298 in building E40 (Red brick building) The main
conference room is right in front of the Elevators on the second
floor. Come by around 6:45-7pm. As I understand it the room
is booked until 9pm.
Thanks greatly to …