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实战低成本服务器搭建千万级数据采集系统 - 更多技术 - 清泛网 - 专注C/C++...
...法。由于有两个表作为数据插入表，使用数据库表的自增id并不太合适，需要一个高速的唯一自增Id服务器提供生成分布式ID。另数据库完全可以关闭写事务日志 ，提高性能，因为抓取的数据当时丢失再启动抓取就可以了， 这样...
Float right and position absolute doesn't work together
...or your help. I use left:50% and margin-left:-??px (?? depend on your div width)
– trbaphong
Jul 4 '12 at 20:46
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Why sizeof int is wrong, while sizeof(int) is right?
...have introduced a rule to resolve the ambiguity, but I can imagine why it didn't bother. With the language as it stands, a type specifier never appears "naked" in an expression, and so there is no need for rules to resolve whether that second * is part of the type or an arithmetic operator.
The exi...
Swift alert view with OK and Cancel: which button tapped?
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anyone knows how to add accessibility id to "ok" and "cancel" actions
– Kamaldeep singh Bhatia
Nov 7 '17 at 11:21
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Make page to tell browser not to cache/preserve input values
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All of the answers and suggestions didnt work for me. Using chrome and develeoping .net
– hakan
Jun 8 '14 at 10:45
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Laravel Eloquent groupBy() AND also return count of each group
...et collection, groupBy and count:
$collection = ModelName::groupBy('group_id')
->selectRaw('count(*) as total, group_id')
->get();
Cheers!
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Why can't I do ?
...d the why and gave some ways around it. What I'll likely do (and I know I didn't provide much background) is create a local webserver to serve local images. That way the browser can display them.
– PeterV
Nov 4 '10 at 1:26
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SQL to determine minimum sequential days of access?
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The answer is obviously:
SELECT DISTINCT UserId
FROM UserHistory uh1
WHERE (
SELECT COUNT(*)
FROM UserHistory uh2
WHERE uh2.CreationDate
BETWEEN uh1.CreationDate AND DATEADD(d, @days, uh1.CreationDate)
) = @days OR UserId = 52551
E...
How can I return to a parent activity correctly?
I have 2 activities (A and B) in my android application and I use an intent to get from activity A to activity B. The use of parent_activity is enabled:
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Google Maps zoom control is messed up
... used to zoom the map is messed up (it wasn't always like this). I have no idea what the cause is.
9 Answers
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