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Showing posts with the label MySQL

Server Crash... Bad Memory

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I've spent about three hours checking and sorting out the machine which went down, and come-what may I found problem after problem, but not with any of the software.  If your software checks out then there's an obvious other place to look... Your hardware. My first step was to remove the drives, specifically my ZFS devices.  No difference, everything still broke. I then set about systematically removing one piece of hardware at a time, first my quad ethernet card, no difference, then I removed the added dual SATA card still broke... Finally, I removed all the memory and inserted just one stick... For the first time the firmware of the motherboard reported something had changed (at boot) it knew the memory has reduced from 8GB to 2GB.  But then the grub boot was really fast, it came up and into the system very quickly. Now, I had been getting MySQL Error 2013 for nearly ever query or SQL dump, with 2GB of RAM this didn't happen, sudo and all the programs now work again... ...

Development : No Great Shakes at SQL

I was just handed a technical test, this was for a job interview, and I was a little... well I'll say surprised, but then shocked, by the reply, lets take a look... I was handed these SQL statements, in several questions, and then told to summarise what I should see on any output of the various instructions.... create table customers (id INTEGER PRIMARY KEY, name Text, age INTEGER, weight REAL); insert into customers values(73, "Brian", 42, 33); insert into customers values(1, "Helen", 12, 12.5); select * from customers; SELECT name, CASE WHEN age > 18 THEN "adult" ELSE "minor" END "type" FROM customers; create table orders (id INTEGER PRIMARY KEY, customer_id INTEGER, desc TEXT); insert into orders values (0, 73, "Apples"); insert into orders values (1, 73, "Oranges"); insert into orders values (2, 1, "Bananas"); select * from orders; SELECT customers.name, orders.desc FROM customers JOIN orders ON ...