996 karma · joined April 4, 2014
[0] https://en.wikipedia.org/wiki/Digest_access_authentication
How do such low mass black holes form?
We're talking much more than just index optimizations. Think automatic OLTP vs. OLAP pattern detection and migration of data into columnstores or in-memory tables. Automatic detection of cold vs. hot data and migration to-from expensive fast near storage (SSD) vs. cheap remote storage (S3 like). Automatic resizing of instance size. Materialized views. On-the-fly query rewrite. The field is wide open. And you have the best experts in the field looking at your database.
By contrast, the traditional on-premise auto-tuning did not made much progress over the past 10-15 years. There are reasons for this: small operational dataset (one site only), high risk of regression (difficult to do A/B testing), scarcity of experts. The best avenue for on-premise I predict will be the trickle-down effect of migrating service know-how and technologies to on-premise offerings. We're also going to see a push up the stack of the know-how and experience from operating the service making its way into the app stack (think EntityFramework v. 2018?) and helping developers avoid the common pitfalls.
BTW, only 3 days ago Adrian Coyler's morning paper discussion was Self-driving database management systems [2]
[1] https://docs.microsoft.com/en-us/azure/sql-database/sql-data... [2] https://blog.acolyer.org/2017/01/17/self-driving-database-ma...
- https://blogs.technet.microsoft.com/winserverperformance/2008/04/25/designing-applications-for-high-performance-part-1/
- https://blogs.technet.microsoft.com/winserverperformance/2008/05/20/designing-applications-for-high-performance-part-ii/
- https://blogs.technet.microsoft.com/winserverperformance/2008/06/25/designing-applications-for-high-performance-part-iii-2/
A simplified explanation is that for good throughput one creates a completion port and binds a thread pool to it with as many threads as CPUs. Then all IO is done via the completion port. If the system is partitioned (NUMA) then one should create a completion port per node and partition the thread pool. I skip the details, read the links for a better explanation. The gist of it that the code written this way has no procedural flow when you read it. Instead of a sequence of function calls (read socket -> parse -> read file -> write socket), it must be a state machine which always reacts to some IO completion, modifies the state, posts some more IO and then returns the thread back to the pool (post socket read, socket read callback -> parse -> post file read, file read callback -> post socket write, write socket callback). Writing it as FSM makes it lot easier to understand.C# async/await is like a DSL that generates the FSM while you write fluent sequential code, easy to write and easy to read.
Even when finally it was aknowledged that the command shell needs some love too, the answer was PowerShell, which yet again defined an object interface between cmdlets[4].
[0] https://en.wikipedia.org/wiki/Dynamic_Data_Exchange [1] https://en.wikipedia.org/wiki/Object_Linking_and_Embedding [2] https://en.wikipedia.org/wiki/Component_Object_Model [3] https://en.wikipedia.org/wiki/Local_Procedure_Call [4] https://en.wikipedia.org/wiki/PowerShell#Pipeline
> Meteorites can churn up the lunar surface in several ways. Along with the fresh craters, Speyerer's team found more than 47,000 ‘splotches’, formed when material gets kicked up by the main impact and rains down — sometimes tens of kilometres away.
> And that means a bigger risk for any future lunar habitats, says Stephanie Werner, a planetary geologist at the University of Oslo. The chances of a lunar base being nailed by a direct meteorite hit are relatively small, but the splattered material could pose a hazard.
"found that 10 times as many galaxies were packed into a given volume of space in the early universe than found today. Most of these galaxies were relatively small and faint, with masses similar to those of the satellite galaxies surrounding the Milky Way. As they merged to form larger galaxies the population density of galaxies in space dwindled. This means that galaxies are not evenly distributed throughout the universe's history,"
I read this as they did not find new visible matter, but they discovered that the visible matter was distributed in many more small galaxies compared with today. I could be wrong though, I'm by no means an expert in this field.
I'm thinking at this as proof of concept. If it works, there are many rich areas of the globe where fertile soil is at a premium and cannot grow much. Basically, transform oil dollars into local grown food.
> The forelimb of Drepanosaurus is highly modified compared to other vertebrates and very robust. Its ulna was altered from being a forearm bone into an odd crescent shaped site for muscle attachment. The role played by the ulna in most tetrapods is replaced by an elongated carpal bone. Additional musculature would be attached to the high withers that characterized Drepanosaurus and its close relatives.
What fascinates me and triggered me to submit here is how similar (in spirit) this adaptation is to the famous Panda's Thumb [1].
- [0] https://en.wikipedia.org/wiki/Drepanosaurus
- [1] https://en.wikipedia.org/wiki/The_Panda%27s_Thumb_(book)
[0] http://www.mindview.net/Etc/Discussions/CheckedExceptions/