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Best way to select random rows PostgreSQL
... not only reads that table but also involves reading and writing temporary files. The where random() < 0.1 only scans the complete table once.
For large tables this might not what you want as even one complete table scan might take to long.
A third proposal would be
select * from table where r...
How to link godaddy domain with AWS Elastic Beanstalk environment?
...copy servers:
In GoDaddy's Domain Manager export records via "Export Zone File (Windows)".
Import those records to Route 53 ("Import Zone File" button).
In GoDaddy's Domain Manager set custom DNS nameservers, obtained on the 2nd step:
Migrating might take some time (even days).
Now you can link ...
Is there an equivalent of CSS max-width that works in HTML emails?
...
@PhyllisSutherland found a fix for images: <img src="file.jpg" "width="350" alt="" style="display:block;width:100%" /> litmus.com/community/discussions/…
– cbron
Oct 3 '17 at 21:47
...
What is the difference between NaN and None?
I am reading two columns of a csv file using pandas readcsv() and then assigning the values to a dictionary. The columns contain strings of numbers and letters. Occasionally there are cases where a cell is empty. In my opinion, the value read to that dictionary entry should be None but instead ...
Turn a simple socket into an SSL socket
...ions(sslctx, SSL_OP_SINGLE_DH_USE);
int use_cert = SSL_CTX_use_certificate_file(sslctx, "/serverCertificate.pem" , SSL_FILETYPE_PEM);
int use_prv = SSL_CTX_use_PrivateKey_file(sslctx, "/serverCertificate.pem", SSL_FILETYPE_PEM);
cSSL = SSL_new(sslctx);
SSL_set_fd(cSSL, newsockfd );
//Here is the S...
Is there a performance difference between i++ and ++i in C?
... f()
{
int i;
for (i = 0; i < 100; i++)
g(i);
}
The files are the same, except for ++i and i++:
$ diff i++.c ++i.c
6c6
< for (i = 0; i < 100; i++)
---
> for (i = 0; i < 100; ++i)
We'll compile them, and also get the generated assembler:
$ gcc -c i++.c +...
How slow are .NET exceptions?
...erting data from a user. It's appropriate when reading a machine-generated file, where failure means "The file isn't in the format it's meant to be, I really don't want to try to handle this as I don't know what else might be wrong."
When using exceptions in "only reasonable circumstances" I've nev...
In absence of preprocessor macros, is there a way to define practical scheme specific flags at proje
...ags appropriately all the time for each language.
For ours, we declared a file in ObjC
PreProcessorMacros.h
extern BOOL const DEBUG_BUILD;
In the .m
PreProcessorMacros.m
#ifdef DEBUG
BOOL const DEBUG_BUILD = YES;
#else
BOOL const DEBUG_BUILD = NO;
#endif
Then, in your Objective-C Br...
Should I use #define, enum or const?
...ng them in a namespace is cool. If they are declared in your CPP or header file, their values will be inlined. You'll be able to use switch on those values, but it will slightly increase coupling.
Ah, yes: remove the static keyword. static is deprecated in C++ when used as you do, and if uint8 is a...
When to use MongoDB or other document oriented database systems? [closed]
...nd and recently included MongoDB for storing all meta-information of the files, because MongoDB better fits the requirements. For example: photos may have Exif information, videos may have audio-tracks where we to want to store the meta-information of, too. Videos and vector-graphics don't share...