IT Hare on Soft.ware

Disclosure: On this site you won’t find specific advice on “how to call function xyz()”. Interpreting C++ ARM and #pragma dwim is also out of scope.

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We’re treating our readers as intelligent beings who can use Google and/or StackOverflow, where all such specific questions were answered more than once.

What you will find is opinions on all the aspects of software development (from UI to scalability, reliability and security) for all kinds of systems (from large-scale systems to embedded ones), the reasoning behind those opinions, and tons of practical observations, which may help you to choose what you really need for your specific task.

Your mileage may vary. Batteries not included.

DB Execution Plans for C++/Java Developers, and for anybody who has read Knuth

Quote:

“If I was a compiler-with-ability-to-create-indexes-as-I-need-it – what would I do to make The Ideal Execution Plan™ for this request?”

Another Quote:

“When we have that ideal-execution-plan – we still need to convince our SQL compiler to use it”

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Understanding Correlated and Uncorrelated Sub-queries in SQL

Quote:

“A correlated sub-query is a type of query, where inner query depends upon the outcome of the outer query in order to perform its execution.”

Another Quote:

“Correlated sub-queries are slower.”

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OLTP DB Optimizations 101 – Thinking in Terms of Execution Plans

Quote:

“to realize how our queries are working – we need to start thinking in terms of so-called “execution plans”.”

Another Quote:

“it can be faster to use Table Scan rather than Index-Scan+fetch over such a low-selectivity index”

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Allocator for (Re)Actors with Optional Kinda-Safety and Relocation

Quote:

“‘Safe with relocation’ mode will allow us to eliminate dreaded ‘external fragmentation’ – which tends to cause quite a bit of trouble for long-running systems”

Another Quote:

“For a long while, I have been a strong proponent of message-passing mechanisms over mutex-based thread sync for concurrency purposes”

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The Importance of Back-of-Envelope Estimates

Quote:

“trying to optimize out a 3e-7 performance hit is very rarely worth the trouble.”

Another Quote:

“With 4S/4U boxes having typical MTBFs of 3–5 years, the next question we should ask ourselves, is “Hey, will we really be able to write software which crashes much more rarely than that?””

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(Not Really So) New Niche for C++: Browser!?

Quote:

“asm.js has invented its own instruction set, which can be still seen as an instruction set of a CPU, at least from the point of view of a C++ compiler.”

Another Quote:

“As asm.js is a strict subset of JavaScript – it will run even if there is no special support for asm.js in browser.”

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Access Control for Admin Tools

Quote:

“You DO need access control for your CSRs.”

Another Quote:

“This approach means that we can have our cake (have tree-like structures to express access rights) and eat it too (have very fast SQL for checking access)”

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