SEARCH KEYWORD -- SQL Server
Easy Parallel Processing in PHP
The proliferation of multicore CPUs and the inability of our learned CPU vendors to squeeze many more GHz into their designs means that often the only way to get additional performance is by writing clever parallel software. One problem we were having is that some of our batch processing jobs were taking too long to run. In order to speed the processing, we tried to split the processing file into half, and let a separate PHP process run each job. Given that we were using a dual core serv...
PHP,Parallel processing,Multithreading like,Sleep 2011-12-12 10:58:59
Top 5 Reasons Not to Use Hadoop for Analytics
As a former diehard fan of Hadoop, I LOVED the fact that you can work on up to Petabytes of data. I loved the ability to scale to thousands of nodes to process a large computation job. I loved the ability to store and load data in a very flexible format. In many ways, I loved Hadoop, until I tried to deploy it for analytics. That’s when I became disillusioned with Hadoop (it just "ain't all that"). At Quantivo, we’ve explored many ways to deploy H...
Cloud computing,Hadoop,Analytics 2012-04-17 13:43:26
SQL Grammar Summary
æ•´ç†äº†ä¸€ä¸‹ï¼Œå¸Œæœ›å¯¹å¤§å®¶æœ‰ç”¨SQLè¯å¥å¤§å…¨ --è¯ å¥ åŠŸ 能--æ•°æ®æ“作SELECT --从数æ®åº“表ä¸æ£€ç´¢æ•°æ®è¡Œå’Œåˆ—INSERT --å‘æ•°æ®åº“è¡¨æ·»åŠ æ–°æ•°æ®è¡ŒDELETE --从数æ®åº“表ä¸åˆ 除数æ®è¡ŒUPDATE --æ›´æ–°æ•°æ®åº“表ä¸çš„æ...
SQL,Query,Summary,Select,Update,Delete,I 2011-05-20 12:04:55
How Query Optimizer Works in RDBMS
In a previous post, we discussed how the various relational operators are implemented in relational database systems. If you have read that post, you probably still remember that there are a few alternative implementations for every operator. Thus, how should RDBMS determine which algorithm (or implementation) to use? Obviously, to optimize the performance for any query, RDBMS has to select the correct the algorithm based on the query. It would not be desirable to always use the same algori...
DATABASE,DATABASE DESIGN,DATABASE OPTIMIZATION 2019-04-20 07:26:32
The details and analysis of capturing gRPC packets
Introduction If you're only using gRPC at the application layer, I believe studying the examples on the gRPC official website is sufficient. However, when planning to extensively use gRPC within a team, you will face many challenges, such as authentication schemes between services, routing solutions for multi-region services, and compatibility solutions with existing RESTful services. I recently realized that applying a technology stack requires mastering a wealth of information about that stack...
Remote execute command in Java example
Frequently there is a need to logon to a remote system and run some commands or programs to get the output, many software can serve this purpose such as putty and gitshell.These software usually provide secure access to the remote system. But have you ever wondered what to do if you need to run commands on many different systems at the same time and get all these results back at a single place? Especially in big data era, many tasks may run on different distributed systems and you want o have a ...
JSch, Example, Distributed system, SSH2 2014-12-12 03:20:19
Create host only network on VirtualBox
Previously we showed how to install Ubuntu in VirtualBox. What if we want to communicate with the host OS from within the Guest OS on VirtualBox? There are a few ways to do this. For example, bridged network, Host only networks. Today we will show you how to enable network communication between host OS and guest OS using host only networks. A host only network will not need to access the physical network interface of the host OS. It will create a network between different virtual machines and th...
VIRTUALBOX,NETWORK,VIRTUAL MACHINE,HOST-ONLY 2015-12-01 09:29:13
One reason why mcrypt responds slowly
This morning one colleague came over and talked about one script which used mcrypt responded very slowly, the server configurations are fine. But the reason for the slowness is unknown. Here is one script which reproduces the issue: <?php $dmcryptText = "dummy"; $key = "foobar"; $size = mcrypt_get_iv_size(MCRYPT_BLOWFISH,MCRYPT_MODE_ECB); $iv = mcrypt_create_iv($size); //Take care $m = mcrypt_ecb(MCRYPT_BLOWFISH, $key, $dmcryptText, MCRYPT_DECRYPT, $iv); var_dump($m); When 20 requests of&...
Setting server timezone
To set your web servers date timezone, for example for Eastern Standard Time (EST) use the following code:SetEnv TZ America/IndianapolisFor example, for Los Angeles time (Pacific time), use the following code:SetEnv TZ America/Los_AngelesOther location examples include:America/New_York - Eastern Time America/Detroit - Eastern Time - Michigan (most locations) America/Louisville - Eastern Time (Louisville, Kentucky) America/Indianapolis - Eastern Standard Time (Indiana, most locatio...
Do You Morph Into A Different Programmer?
Every experience you have as a software developer should change you in some way. And I don’t just mean growing older by virtue of time passing. Everything you do should evolve your understanding of your craft (and/or related skills) or your understanding of yourself – which ultimately achieves the same goal. I am not just talking about major milestones in your software development career like switching jobs, becoming a leader/manager or starting you own company. Every job, ev...
Programmer,Steps,Process,Developer 2011-08-18 08:59:01
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