Purpose of this article:
Firmware upgrade may not be successful sometimes, for instance unpredictable power failure during the process, and thus your Pharos device may fail to reboot. This article will guide you how to re-flash the firmware via TFTP.
Continue reading “[Knowledge Base] How to use firmware recovery function of Pharos CPE”
JBossProperties | JBoss Developer
JBoss Properties
There are a number of properties used by the micro-kernel during the bootstrap.
This documentation is heavily plagiarized from org.jboss.system.server.ServerConfig. Continue reading “JBossProperties | JBoss Developer”
Diff util cheatsheet
“C:\Program Files\KDiff3\kdiff3.exe” %base %mine %theirs -o %merged –L1 Base –L2 Mine –L3 Theirs
C:\Program Files (x86)\Meld\Meld.exe -n
VBA Excel–Allow Paste Special Only
While recently answering a post on the MSDN forum, I realized that the Robert Gold(Vice President of Business Intelligence in Bostwick Laboratories, Inc) was facing the same problem that I was facing couple of years back when I was working as a Team Leader in one of the BPO’s. The MIS Department was reporting to me and one of the main jobs was to create “Trackers” for various departments. My team used to take hours to design a particular tracker only to realize after few days that the users were spoiling the format of the tracker by copying and pasting. Completely protecting it with a password was not the option. Nor did we find any option in Excel which forced selective pasting. It was then we devised this macro which allowed the user to paste but behind the scenes, converted that paste into paste special – values.
The only drawback of this method is that if the macros are disabled then this won’t work. But thanks to the IT Department, they ensured that the macros was enabled on each and every pc. After that we never faced a problem with users messing up the format of the sheet.
So how does this code work? What is the logic behind it? I would explain this in 3 sections.
- Logic
- Planting the Code
- Code
JDBC connection to very busy SQL 2000: selectMethod=cursor vs selectMethod=direct? – Stack Overflow
Briefly,
selectMethod=cursor
- theoretically requires more server-side resources than
selectMethod=direct
- only loads at most batch-size records into client memory at once, resulting in a more predictable client memory footprint
- theoretically requires more server-side resources than
selectMethod=direct
- theoretically requires less server-side resources than
selectMethod=cursor
- will read the entire result set into client memory (unless the driver natively supports asynchronous result set retrieval) before the client application can iterate over it; this can reduce performance in two ways:
- reduced performance with large result sets if the client application is written in such a way as to stop processing after traversing only a fraction of the result set (with
direct
it has already paid the cost of retrieving data it will essentially throw away; withcursor
the waste is limited to at most batch-size – 1 rows — the early termination condition should probably be recoded in SQL anyway e.g. asSELECT TOP
or window functions) - reduced performance with large result sets because of potential garbage collection and/or out-of-memory issues associated with an increased memory footprint
- reduced performance with large result sets if the client application is written in such a way as to stop processing after traversing only a fraction of the result set (with
- theoretically requires less server-side resources than
In summary,
- Can using
selectMethod=cursor
lower application performance? — either method can lower performance, for different reasons. Past a certain resultset size,cursor
may still be preferable. See below for when to use one or the other - Is
selectMethod=
an application-transparent setting on a JDBC connection? — it is transparent, but it can still break their app if memory usage grows significantly enough to hog their client system (and, correspondingly, your server) or crash the client altogether
Source: JDBC connection to very busy SQL 2000: selectMethod=cursor vs selectMethod=direct? – Stack Overflow
Sequences are incremented twice
When a sequence is incremented twice when running SELECT NEXT VALUE FOR MYSEQ; and you are using the Microsoft JDBC driver with the selectMethod=cursor, remove the selectMethod=cursor option from the JDBC URL. The sequences will then be incremented correctly.
Spring @Transactional explained | DuyHai’s Java Blog
Spring is a widely used framework today, bringing many powerfull features and extensions to the Java core stack. However most of people tend to use these features without understanding their underlying mechanism.
Since there is no “magic” in real life, we are going to dig into some Spring features related to Transaction and Database in this serie of articles.
This first article is dealing with the famous @Transactional annotation, saving the developers the burden of managing low level transaction code.
Continue reading “Spring @Transactional explained | DuyHai’s Java Blog”
35+ Use Cases for Choosing Your Next NoSQL Database – High Scalability –
We’ve asked What The Heck Are You Actually Using NoSQL For?. We’ve asked 101 Questions To Ask When Considering A NoSQL Database. We’ve even had a webinar What Should I Do? Choosing SQL, NoSQL or Both for Scalable Web Applications.
Now we get to the point of considering use cases and which systems might be appropriate for those use cases. Continue reading “35+ Use Cases for Choosing Your Next NoSQL Database – High Scalability –”
Generic Types (The Java™ Tutorials > Learning the Java Language > Generics (Updated))
By convention, type parameter names are single, uppercase letters. This stands in sharp contrast to the variable naming conventions that you already know about, and with good reason: Without this convention, it would be difficult to tell the difference between a type variable and an ordinary class or interface name.
The most commonly used type parameter names are:
- E – Element (used extensively by the Java Collections Framework)
- K – Key
- N – Number
- T – Type
- V – Value
- S,U,V etc. – 2nd, 3rd, 4th types
You’ll see these names used throughout the Java SE API and the rest of this lesson.
Source: Generic Types (The Java™ Tutorials > Learning the Java Language > Generics (Updated))