大约有 14,600 项符合查询结果（耗时：0.0265秒） [XML]
PostgreSQL ERROR: canceling statement due to conflict with recovery
... updated or deleted on primary. As a primary does not know that a query is started on secondary it thinks it can clean up (vacuum) old versions of its rows. Then secondary has to replay this cleanup, and has to forcibly cancel all queries which can use these rows.
Longer queries will be canceled mo...
Proper use of beginBackgroundTaskWithExpirationHandler
...
Only if you want to use that as a point to start the network operation. If you just want an existing operation to complete, as per @Eyal's question, you don't need to do anything in applicationDidEnterBackground
– Ashley Mills
Au...
How do I set the size of Emacs' window?
I'm trying to detect the size of the screen I'm starting emacs on, and adjust the size and position the window it is starting in (I guess that's the frame in emacs-speak) accordingly. I'm trying to set up my .emacs so that I always get a "reasonably-big" window with it's top-left corner near the top...
is node.js' console.log asynchronous?
...
Update: Starting with Node 0.6 this post is obsolete, since stdout is synchronous now.
Well let's see what console.log actually does.
First of all it's part of the console module:
exports.log = function() {
process.stdout.write(...
Regex to validate password strength
...[a-z].*[a-z]).{8}$
Rubular link
Explanation:
^ Start anchor
(?=.*[A-Z].*[A-Z]) Ensure string has two uppercase letters.
(?=.*[!@#$&*]) Ensure string has one special case letter.
(?=.*[0-9].*[0-9]) Ensure string has two digits.
(?=.*[a-z].*[a-z...
What does Redis do when it runs out of memory?
...y functionality turned on (new in version 2.0 or 2.2, I think), then Redis starts to store the "not-so-frequently-used" data to disk when memory runs out.
If virtual memory in Redis is disabled, it appears as if the operating system's virtual memory starts to get used up (i.e. swap), and performanc...
Constructors vs Factory Methods [closed]
...with interfaces).
And this is the main difference and advantage. When you start dealing with a complex class hierarchies and you want to dynamically create an instance of a class from such a hierarchy you get the following code. Factory methods might then take a parameter that tells the method what...
querySelector search immediate children
...
You can't. There's no selector that will simulate your starting point.
The way jQuery does it (more because of a way that qsa behaves that is not to their liking), is that they check to see if elem has an ID, and if not, they temporarily add an ID, then create a full selector st...
How do I detect “shift+enter” and generate a new line in Textarea?
... caret column (not pixels) position in a textarea, in characters, from the start?
function getCaret(el) {
if (el.selectionStart) {
return el.selectionStart;
} else if (document.selection) {
el.focus();
var r = document.selection.createRange();
if (r == n...
What is an Intent in Android?
...
Actually an action means you can start one component from another component using an Intent. That is what it is primarily used for.
– Sreekanth Karumanaghat
Sep 13 '17 at 13:11
...