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内存优化总结:ptmalloc、tcmalloc和jemalloc - 操作系统(内核) - 清泛网 - ...
... 总共32个vcpu。 16个table，每个5M row。
OLTP_RO测试包含5个select查询：select_ranges, select_order_ranges, select_distinct_ranges, select_sum_ranges,
可以看到在多核心或者多线程的场景下， jemalloc和tcmalloc带来的tps增加非常明显。
参考资料
glibc...
How do I get a substring of a string in Python?
...is a step. So reversing a string is as simple as:
some_string[::-1]
Or selecting alternate characters would be:
"H-e-l-l-o- -W-o-r-l-d"[::2] # outputs "Hello World"
The ability to step forwards and backwards through the string maintains consistency with being able to array slice from the star...
What should I do when 'svn cleanup' fails?
...ools-win32) from http://www.sqlite.org/download.html
sqlite3 .svn/wc.db "select * from work_queue"
The SELECT should show you your offending folder/file as part of the
work queue. What you need to do is delete this item from the work
queue.
sqlite3 .svn/wc.db "delete from work_...
Why does “_” (underscore) match “-” (hyphen)?
...u want to use the underscore in like as a literal, you have to escape it:
select * from a where name like '%taz\_manual%.pdf%';
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Is there a way to suppress warnings in Xcode?
... Easy way to get the warning code: go to the Log Navigator (Command+7), select the topmost build, expand the log (the '=' button on the right), and scroll to the bottom.
– Neal Ehardt
Jan 25 '12 at 16:46
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How to set a default value for an existing column
...able and found this way to check if it had been done already... IF EXISTS(SELECT * FROM information_schema.columns WHERE table_name='myTable' AND column_name='myColumn' AND Table_schema = 'myDBO' AND column_default IS NULL) BEGIN ALTER TABLE [myDBO].[myTable] ADD DEFAULT 0 FOR [myColumn] END
...
How can I open a cmd window in a specific location?
...ing you a
quick way to open a command window
(cmd.exe) pointing at the selected
folder.
EDIT : This software will not work on any version of Windows apart from Windows XP.
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How to log PostgreSQL queries?
...ement = 'all'
#logging_collector = off to logging_collector = on
Optional: SELECT set_config('log_statement', 'all', true);
sudo /etc/init.d/postgresql restart or sudo service postgresql restart
Fire query in postgresql select 2+2
Find current log in /var/lib/pgsql/9.2/data/pg_log/
The log files t...
Using 'starts with' selector on individual class names
...thought of using space in there. Can one use boolean operators in a jquery selector? Ideally, the above would be 'OR' to avoid the (rare and likely avoidable) case where there are more than one class staring with 'apple-'
– DA.
Feb 1 '10 at 17:12
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How to apply unmerged upstream pull requests from other forks into my fork?
...ew pull request
The pending pull request(s) should be offered. Remember to select proper OtherFork branch too. Select on the left side as the base fork your fork (MyFork) (IMPORTANT).
Now the option of View pull request should change to Create pull request. Click this.
Now you should have a pending...