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How to debug Lock wait timeout exceeded on MySQL?
...query, all the tables being accessed are candidates for being the culprit.
From there, you should be able to run SHOW ENGINE INNODB STATUS\G
You should be able to see the affected table(s)
You get all kinds of additional Locking and Mutex Information.
Here is a sample from one of my clients:
mysql&g...
AJAX Mailchimp signup form integration
...ass.php'); // same directory as store-address.php
// grab an API Key from http://admin.mailchimp.com/account/api/
$api = new MCAPI('123456789-us2');
$merge_vars = Array(
'EMAIL' => $_GET['email'],
'FNAME' => $_GET['fname'],
'LNAME' => $_GET['lname']
...
Random String Generator Returning Same String [duplicate]
...class are NOT documented as being thread-safe, so if this method is called from multiple threads at the same time (highly likely if you're making a web app, for example) then the behaviour of this code will be undefined. You either need to use a lock on the random or make it per-thread.
...
UDP vs TCP, how much faster is it? [closed]
... for you.
On a larger scale, this TCP behavior is what keeps the Internet from locking up into "congestion collapse".
Things that tend to push applications towards UDP:
Group delivery semantics: it's possible to do reliable delivery to a group of people much more efficiently than TCP's point-to...
Rails 2.3-style plugins and deprecation warnings running task in Heroku
...
Yep, I realize that all the warnings came from my Heroku scripts and logs. I'll assume that (a) it's the plugin injections and (b) that the Heroku team will fix this before it becomes an actual problem.
– fearless_fool
Jan 28 '...
MongoDB/NoSQL: Keeping Document Change History
...are a number of ways to approach it in an RDBMS--you can write all changes from all source tables to a single table (more of a log) or have a separate history table for each source table. You also have the option to either manage the logging in application code or via database triggers.
...
Failed to execute 'btoa' on 'Window': The string to be encoded contains characters outside of the La
...this to work in mobile-safari, you might need to strip all the white-space from the base64 data...
function b64_to_utf8( str ) {
str = str.replace(/\s/g, '');
return decodeURIComponent(escape(window.atob( str )));
}
2017 Update
This problem has been bugging me again.
The simple tr...
Why does this Java program terminate despite that apparently it shouldn't (and didn't)?
...hose 4 write operations can be freely reordered by the compiler / JVM.
So from the perspective of the reading thread, it is a legal execution to read x with its new value but y with its default value of 0 for example. By the time you reach the println statement (which by the way is synchronized and...
How can I use pointers in Java?
... cannot allocate the requested cell. This is very rare and usually results from run-away recursion.
Note that, from a language point of view, abandoning objects to the garbage collector are not errors at all. It is just something that the programmer needs to be aware of. The same variable can point...
What does “Memory allocated at compile time” really mean?
...al addresses. The program assumes that it has its own entire memory space (From 0x00000000 to 0xFFFFFFFF for example). That's why the compiler could do assumptions like "Okay, the array will be at address 0x00A33211". At runtime that addresses are translated to real/hardware addresses by the MMU and...