There is a lot of things you can do with Raspberry Pi, but for retro-game lover it can be a dream project enabler. Continue reading “Ultimate iCade Raspberry Pi bartop arcade mod – Part I – The Hardware”
Force Xbian resize partition when moving to bigger card
I have encountered this when moving my Xbian installation from 8GB card to 32GB one. The solution is to copy everything and force it to resize to 32GB.
1. dd copy old SD card to new bigger SD card (for example:
dd if=/dev/sdd of=/dev/sde bs=4M
where sdd is your old card and sde is your new SD card. Continue reading “Force Xbian resize partition when moving to bigger card”
How to get recommended key_buffer_size in MySQL
Execute following command in mysql shell by connecting with your username and password:
mysql> SELECT CONCAT(ROUND(KBS/POWER(1024,
IF(PowerOf1024<0,0,IF(PowerOf1024>3,0,PowerOf1024)))+0.4999),
SUBSTR(' KMG',IF(PowerOf1024<0,0,
IF(PowerOf1024>3,0,PowerOf1024))+1,1))
recommended_key_buffer_size FROM
(SELECT LEAST(POWER(2,32),KBS1) KBS
FROM (SELECT SUM(index_length) KBS1
FROM information_schema.tables
WHERE engine='MyISAM' AND
table_schema NOT IN ('information_schema','mysql')) AA ) A,
(SELECT 3 PowerOf1024) B;Response will be something like this:
+-----------------------------+ | recommended_key_buffer_size | +-----------------------------+ | 1G | +-----------------------------+ 1 row in set (0.08 sec)
When I used this calculation for my Raspberry Pi 2 running MySQL result was 0G, so you need to modify the query to show either MB or KB values by using:
For key_buffer_size recommended size in MB:
SELECT CONCAT(ROUND(KBS/POWER(1024, IF(PowerOf1024<0,0,IF(PowerOf1024>3,0,PowerOf1024)))+0.4999), SUBSTR(' KMG',IF(PowerOf1024<0,0, IF(PowerOf1024>3,0,PowerOf1024))+1,1)) recommended_key_buffer_size FROM (SELECT LEAST(POWER(2,32),KBS1) KBS FROM (SELECT SUM(index_length) KBS1 FROM information_schema.tables WHERE engine='MyISAM' AND table_schema NOT IN ('information_schema','mysql')) AA ) A, (SELECT 2 PowerOf1024) B;Result:
+-----------------------------+ | recommended_key_buffer_size | +-----------------------------+ | 1M | +-----------------------------+ 1 row in set (0.44 sec)
For key_buffer_size recommended size in KB:
SELECT CONCAT(ROUND(KBS/POWER(1024, IF(PowerOf1024<0,0,IF(PowerOf1024>3,0,PowerOf1024)))+0.4999), SUBSTR(' KMG',IF(PowerOf1024<0,0, IF(PowerOf1024>3,0,PowerOf1024))+1,1)) recommended_key_buffer_size FROM (SELECT LEAST(POWER(2,32),KBS1) KBS FROM (SELECT SUM(index_length) KBS1 FROM information_schema.tables WHERE engine='MyISAM' AND table_schema NOT IN ('information_schema','mysql')) AA ) A, (SELECT 1 PowerOf1024) B;and result is:
+-----------------------------+ | recommended_key_buffer_size | +-----------------------------+ | 23K | +-----------------------------+ 1 row in set (0.44 sec)