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Distributed sequence number generation?
...d service, i.e. you make a network call to get a unique ID;
which produces 64 bit unique IDs that are ordered by generation time;
and the service is highly scalable and (potentially) highly available; each instance can generate many thousand IDs per second, and you can run multiple instances on your...
How do I install Maven with Yum?
...ved this error: repos.fedorapeople.org/repos/dchen/apache-maven/epel-6/x86_64/…: [Errno 14] HTTPS Error 404 - Not Found Don't know if the repo is temporarily down or permanently down.
– anon58192932
Feb 29 '16 at 21:00
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Compare double to zero using epsilon
...
Assuming 64-bit IEEE double, there is a 52-bit mantissa and 11-bit exponent. Let's break it to bits:
1.0000 00000000 00000000 00000000 00000000 00000000 00000000 × 2^0 = 1
The smallest representable number greater than 1:
1.0000 ...
What are the First and Second Level caches in Hibernate?
...an object is
returned by the query, at that time no need to go for a database
transaction. In this way the second level cache works. Here we can use
query level cache also.
Quoted from: http://javabeat.net/introduction-to-hibernate-caching/
...
Where are Docker images stored on the host machine?
...
648
The contents of the /var/lib/docker directory vary depending on the driver Docker is using for...
range() for floats
...nswer over the accepted one, because the first two solutions presented are based on iterating over integers and deriving the final floats from the integers. This is more robust. If you do it directly with floats, you risk having strange one-off errors due to how floats are represented internally. Fo...
What are best practices for validating email addresses on iOS 2.0
...a-z0-9]+(-[a-z0-9]+)*\\.)+[a-z]{2,4}\\z";
NSString *regex2 = @"^(?=.{1,64}@.{4,64}$)(?=.{6,100}$).*";
NSPredicate *test1 = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", regex1];
NSPredicate *test2 = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", regex2];
return [test1 ev...
How to find a table having a specific column in postgresql
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I've used the query of @Roman Pekar as a base and added schema name (relevant in my case)
select n.nspname as schema ,c.relname
from pg_class as c
inner join pg_attribute as a on a.attrelid = c.oid
inner join pg_namespace as n on c.relnamespace = n.oid
...
.war vs .ear file
...erview:
In J2EE application, modules are packaged as EAR, JAR, and WAR based on their functionality
JAR:
EJB modules which contain enterprise java beans (class files) and EJB deployment descriptor are packed as JAR files with .jar extension
WAR:
Web modules which contain Servl...
How can I shuffle the lines of a text file on the Unix command line or in a shell script?
... to head.
A performance comparison is made.
POSIX-compliant function based on awk, sort, and cut, adapted from the OP's own answer:
shuf() { awk 'BEGIN {srand(); OFMT="%.17f"} {print rand(), $0}' "$@" |
sort -k1,1n | cut -d ' ' -f2-; }
Perl-based function - adapted from Moo...