Haggard 101
It’s already 7am, still have classes by 9am. Haven’t slept since yesterday. And since i woke up, I’ve been coding already. Me, CODING. OH. MY. GOSH. We have this project where we need to make a systrm for the UST hospital. And it’s a one man team. My gosh. My groupmates? I dont know, they just dont care. Ugh. Unfortunately, i became the programmer and all for this project. I was so frustrated, i wasn’t aware that our defense will be that soon. Soon as in a-week-from-now soon. And our system is like 10% only. :( That’s why i was up all night coding, i guess its about 40% now. I dont really code. As in. Php and sql shits are really draining me. :( That’s why i’m really proud of what i did. Hoho! Imma treat myself soon. :> I’m so stressed out. My face is so pale. My eyebags so visible. Ugh. Anyways, my hair is so long already, wanna have a haircut soon. ;)

Today I learned that the total number of tweets ever made on Twitter is roughly 4x the total number of posts ever made on Tumblr.

The number of database servers they have is far, far more than 4x, and ditto for the number of staff members working on their databases. Also keep in mind the average Tumblr post is quite a bit larger than a tweet.

Not knocking Twitter by any means — their work is extremely impressive, especially their open source contributions. But given visibility into the raw numbers, I’m especially proud of the database work my former teams (tiny, tiny teams!) accomplished at Tumblr.

This was taken at a bar I frequent a while back and I just now got around to sharing it.  You get a plate put up on the wall after you finish a certain amount of unique beers in a year; I think it is 100, but I could be mistaken.  This is by far my favorite plate on the wall.  Coding nerds will get it.

Jack Clark for TheRegister quoting Google senior systems engineer, Jeremy Cole’s talk at XLDB:

“Were running primarily on [MySQL] 5.1 which is a little outdated, and so we’re moving to MariaDB 10.0 at the moment,”

I’m wondering how much of this decision is technical and how much is political. While Jack Clark’s points to the previous “disagreements” between Google and Oracle, when I say political decisions I mean more than this: access to the various bits of the code (e.g. tests, security issues), control over the future of the product, etc.

Original title and link: Google moves from MySQL to MariaDB (NoSQL database©myNoSQL)

PHP And MySQL With MySQLi


مدة الـكورس : 1.35 ساعة

حجم الـكورس : 242 MB

صاحب الـكورس : PhpAcademy   

لغة الـكورس : انجليزي

نوع الـكورس : مدفوع (مجاني عندنا)

جودة الـكورس : 720P

————————————————————

محتوى الـكورس :


————————————————————

باسوورد فك الضغط : 

course-web.com

————————————————————

تحميل الـكورس





via Blogger http://ift.tt/XFBdou
5

Here is a visual comparison of what a JOIN MySQL command looks like data-wise. Useful.

Given these two tables:

TableA        TableB
id name       id  name
-- ----       --  ----
1  Pirate     1   Rutabaga
2  Monkey     2   Pirate
3  Ninja      3   Darth Vader
4  Spaghetti  4   Ninja

Inner join produces only the set of records that match in both Table A and Table B.

SELECT * FROM TableA
INNER JOIN TableB
ON TableA.name = TableB.name

id  name       id   name
--  ----       --   ----
1   Pirate     2    Pirate
3   Ninja      4    Ninja

Full outer join produces the set of all records in Table A and Table B, with matching records from both sides where available. If there is no match, the missing side will contain null.

SELECT * FROM TableA
FULL OUTER JOIN TableB
ON TableA.name = TableB.name

id    name       id    name
--    ----       --    ----
1     Pirate     2     Pirate
2     Monkey     null  null
3     Ninja      4     Ninja
4     Spaghetti  null  null
null  null       1     Rutabaga       
null  null       3     Darth Vader

Left outer join produces a complete set of records from Table A, with the matching records (where available) in Table B. If there is no match, the right side will contain null.

SELECT * FROM TableA
LEFT OUTER JOIN TableB
ON TableA.name = TableB.name

id  name       id    name
--  ----       --    ----
1   Pirate     2     Pirate
2   Monkey     null  null
3   Ninja      4     Ninja
4   Spaghetti  null  null

To produce the set of records only in Table A, but not in Table B, we perform the same left outer join, then exclude the records we don’t want from the right side via a where clause.

SELECT * FROM TableA
LEFT OUTER JOIN TableB
ON TableA.name = TableB.name
WHERE TableB.id IS null

id  name       id     name
--  ----       --     ----
2   Monkey     null   null
4   Spaghetti  null   null

To produce the set of records unique to Table A and Table B, we perform the same full outer join, then exclude the records we don’t want from both sides via a where clause.

SELECT * FROM TableA
FULL OUTER JOIN TableB
ON TableA.name = TableB.name
WHERE TableA.id IS null 
OR TableB.id IS null

id    name       id    name
--    ----       --    ----
2     Monkey     null  null
4     Spaghetti  null  null
null  null       1     Rutabaga
null  null       3     Darth Vader

There’s also a cartesian product or cross join.

SELECT * FROM TableA
CROSS JOIN TableB
Watch on isomorphism.es

@bos31337 Running a startup (MailRank) on Haskell (por jasonofthel33t)

Even though this is an advanced talk, there’s still something here for business people who know very little about software but are interested in web startups.

Namely, at Minute 20 BOS ticks off the things that a web app needs to do, like:

  • load balancing requests,
  • proxying data off…
  • for his Haskell code to bang on…
  • in the cloud,
  • receive requests from a Windows desktop software written in C#
  • coördinate those with what he already had,
  • store the data (thus evaluate a database appropriate for their problem),
  • worry about server throughput,
  • connect (bind) his (main) Haskell code to the database, to the server, to the webapp,
  • evaluate server software,

This surveys the moving parts in an internet-based business.

An old, but nonetheless very interesting article from Facebook on the tools they’ve built to automate the management of their MySQL cluster — most probably one of the largest in operation:

MPS is a sophisticated state machine written mostly in Python. It replaces a DBA for many routine tasks and enables us to perform maintenance operations in bulk with little or no human intervention.

Original title and link: MySQL automation at Facebook (NoSQL database©myNoSQL)

Just a strange number from MySQL:

By default 151 is the maximum permitted number of simultaneous client connections in MySQL 5.5

And then the issue related to it:

MySQL uses one thread per client connection and many active threads are performance killer. Usually a high number of concurrent connections executing queries in parallel can cause significant slowdown and increase chances for deadlocks. Prior to MySQL 5.5, it doesn’t scale well although MySQL is getting better and better since then — but still if you have hundreds of active connections doing real work (this doesn’t count sleeping [idle] connections) then the memory usage will grow. Each connection requires per thread buffers. Also implicit in memory tables require more memory plus memory requirement for global buffers. On top of that, tmp_table_size/max_heap_table_size that each connection may use, although they are not allocated immediately per new connection.

Facebook has been doing a lot of work in this area. Just one example: Making MySQL accept connections faster; I strongly encourage you to read if you have a busy MySQL server.

Original title and link: MySQL Error: Too many connections (NoSQL database©myNoSQL)

Text
Photo
Quote
Link
Chat
Audio
Video