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Deleting queues in RabbitMQ
...eues matching a pattern in a given vhost (e.g. containing 'amq.gen' in the root vhost):
rabbitmqctl -p / list_queues | grep 'amq.gen' | cut -f1 -d$'\t' | xargs -I % ./rabbitmqadmin -V / delete queue name=%
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Fast way to discover the row count of a table in PostgreSQL
...in your case.
Instead of getting the exact count (slow with big tables):
SELECT count(*) AS exact_count FROM myschema.mytable;
You get a close estimate like this (extremely fast):
SELECT reltuples::bigint AS estimate FROM pg_class where relname='mytable';
How close the estimate is depends on ...
Android应用内存泄露分析、改善经验总结 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...除其软/弱/虚引用，右键某个类→Merge Shortest Paths to GC Roots→exclude all phantom/weak/soft etc.references。
验证改善效果
  根据个人经验，我一般是这样验证改善效果的，运行程序，各个功能跑一遍，确保没有改出问题，...
How to drop SQL default constraint without knowing its name?
...MySchema'
set @table_name = N'Department'
set @col_name = N'ModifiedDate'
select @Command = 'ALTER TABLE ' + @schema_name + '.[' + @table_name + '] DROP CONSTRAINT ' + d.name
from sys.tables t
join sys.default_constraints d on d.parent_object_id = t.object_id
join sys.columns c on c.object_id ...
iPhone viewWillAppear not firing
...imated to appear or not.)
[myViewController viewWillAppear:NO];
Look at RootViewController.m in the Metronome example.
(I actually found Apple's example projects great. There's a LOT more than HelloWorld ;)
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Better techniques for trimming leading zeros in SQL Server?
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Why don't you just cast the value to INTEGER and then back to VARCHAR?
SELECT CAST(CAST('000000000' AS INTEGER) AS VARCHAR)
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0
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Vim multiline editing like in sublimetext?
...d asd asd asd;
Hit <C-v> to enter visual-block mode and expand your selection toward the bottom:
asd [a]sd asd asd asd;
asd [a]sd asd asd asd;
asd [a]sd asd asd asd;
asd [a]sd asd asd asd;
asd [a]sd asd asd asd;
asd [a]sd asd asd asd;
asd [a]sd asd asd asd;
Hit I"<Esc> to obtain:
asd...
CSS Child vs Descendant selectors
I am a bit confused between these 2 selectors.
8 Answers
8
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typecast string to integer - Postgres
...ur value is an empty string, you can use NULLIF to replace it for a NULL:
SELECT
NULLIF(your_value, '')::int
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Java SecurityException: signer information does not match
...es not match signer information of other classes in the same package
The root problem was that I included the Hamcrest library twice. Once using Maven pom file. And I also added the JUnit 4 library (which also contains a Hamcrest library) to the project's build path. I simply had to remove JUnit f...