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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...
Does Foreign Key improve query performance?
...the foreign key relationship already inforces that for you.
So this:
select p.ProductId, p.Name, c.CategoryId, c.Name AS Category
from Products p inner join ProductCategories c on p.CategoryId = c.CategoryIdwhere c.CategoryId = 1;
Becomes this:
SELECT p.ProductId, p.Name, c.CategoryId, c.N...
Receiving login prompt using integrated windows authentication
...click on your site in IIS under the Sites folder
Click Edit Permissions...
Select the Security tab
Under the Group or usernames section click the Edit... button
In the Permissions pop up, under the Group or user names click Add...
Enter [Domain Users] in the object names to select text area and clic...
Is there a way to create multiline comments in Python?
...
In any case, your text editor should also be able to easily comment-out a selected region (by placing a # in front of each line individually). If not, switch to a text editor that does.
Programming in Python without certain text editing features can be a painful experience. Finding the right edito...
How to handle click event in Button Column in Datagridview?
...ast the sender to type DataGridView, we can get the Columns collection and select the current column using e.ColumnIndex. Then check if that object is of type DataGridViewButtonColumn.
Of course, if you need to distinguish between multiple buttons per grid, you can then select based on the column n...
How to move an element into another element?
...D46y5 As documented in the API: api.jquery.com/appendTo : "If an element selected this way is inserted into a single location elsewhere in the DOM, it will be moved into the target (not cloned) and a new set consisting of the inserted element is returned"
– John - Not A Numbe...
Quickly reading very large tables as dataframes
...
# sqldf as on SO
f <- file("test.csv")
system.time(SQLf <- sqldf("select * from f", dbname = tempfile(), file.format = list(header = T, row.names = F)))
## user system elapsed
## 10.21 0.47 10.73
ff / ffdf
require(ff)
system.time(FFDF <- read.csv.ffdf(file="test.csv",nro...
How do I use WebStorm for Chrome Extension Development?
...ript > Libraries
Click Download
Make sure TypeScript community stubs is selected
Select chrome from the list (you can find it quickly by just typing chrome)
Click Download and Install
Click OK to close the Settings dialog.
Steps 2-6 illustrated below:
In Subsequent Projects
In any subse...
jQuery how to bind onclick event to dynamically added HTML element [duplicate]
...ode. But here he was inserting the elements himself, and there is no clear selector for them (it's just an anchor, which there might be many of), so he would have to add additional markup to be able to target the element. In that case it's just as easy to attach the handler to the element directly, ...
Looking for jQuery find(..) method that includes the current node
...
For jQuery 1.8 and up, you can use .addBack(). It takes a selector so you don't need to filter the result:
object.find('selector').addBack('selector')
Prior to jQuery 1.8 you were stuck with .andSelf(), (now deprecated and removed) which then needed filtering:
object.find('sele...