My understanding of how regular rowstore indexes are stored is in a type of b-tree data structure, but I was wondering because of the different nature of columnstore indexes, what type of underlying data structure is used?
One of the new features in SQL Server 2012 codenamed Denali is the   I know a good bit about regular old row-store indexes, like the b-tree structure, differences in storage between the leaf level and b-tree pages, affects of included fields, optimizing to use them, order of keys, etc.  I'm having difficulty getting any good info on the internals of a columnstore index.     How is it structured? Is there a b-tree?  Some other structure in place? How is data organized? What sorts of specific operators are best suited to use it? Any other anti-patterns to be avoided when using them?   A lot of what I can find out about them are basically the exact opposite of a "normal" index, i.e. no ordering of keys, no included fields, nonclustered ONLY.  Any insights are appreciated.
Checking out  and  (and some papers) was a bit difficult for understanding Group Action. The closest to understanding was this part:    I understand the definition of homomorphism (a structure-preserving map between two algebraic structures of the same type). And from what I understand the symmetric group is a group of functions (bijective functions) mapping elements of a set $X$ onto itself.  However I get confused at this line:     ...an action of $G$ on $X$ may be formally defined as a group homomorphism $\phi$ from $G$ to the symmetric group of $X$.   That seems to be the definition of group action, but I am having trouble understanding how to apply that.  What that says to me is it is a homomorphism (function) $f \colon X \rightarrow S$ where $S$ is a set of bijective functions on $X$. That itself seems weird, I thought a group action would result in a number or something related to $\{1, 2, 3\}$ (defined next).  Continuing, if we have a set $X = \{1, 2, 3\}$ and a group $(*,\{4, 5, 6\})$, then the symmetric group of $X$ would be something like $S = \{1 \rightarrow 2, 2 \rightarrow 3, \dots \}$, and $\phi$ would be something like $f : \{4, 5, 6\} \rightarrow S$. That doesn't make sense to me and I feel like I'm interpreting something wrong. I don't see how mapping to a set of functions $S$ will result in an action on the set. Selecting a database in mysql with spaces in its name I want to select my particular database in mysql console, but the problem is that my database name has a space in between and mysql ignores the part after the space. For instance, when i give the command:  use 'student registration'   I get the message:  cannot find database 'student' What is the Doctor not quite remembering? In season 8 episode 1, when the Doctor encounters the episode's villain(s), he keeps saying that this is all very familiar to him, but he can't quite put a finger on it. Is this a case where the audience is supposed to know more than the Doctor (like when he can't keep Clara and Strax straight), or is he referring to something we (the audience) haven't seen yet? As in, are the serious Whovians yelling at the screen, "it's [insert name of classical Dr. Who villain here]!", or are they as puzzled as the Doctor is (and I am)? Use XeLaTeX in Texmaker instead of pdfLaTeX K&R Exercise 1.16 - Limitation on line length LAN not working on 17.04 Actually yesterday I've upgraded from Ubuntu 16.04 to 17.04 and I got a problem that, if connect LAN cable it does not showing anything and  remains disconnected. But i can connect with WiFi. I don't know what's the problem. Actually its showing "device not managed" under the "Ethernet Network" and both were disabled. I've searched for the solution, but did not found yet. A man sits on a bench considering his woeful burden. He looks up at the stars and compares the distance from here to his house and here to the furthest visible star Deneb. Suddenly his problems seems pitifully faint and untroubling. He laughs and relaxes in his seat, staring at the ducks.     Look again at that dot. That's here, that's home, that's us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every "superstar," every "supreme leader," every saint and sinner in the history of our species lived there—on a mote of dust suspended in a sunbeam.   ~Carl Sagan      I really believe that if the political leaders of the world could see their planet from a distance of 100,000 miles their outlook could be fundamentally changed. That all-important border would be invisible, that noisy argument silenced. The tiny globe would continue to turn, serenely ignoring its subdivisions, presenting a unified façade that would cry out for unified understanding, for homogeneous treatment. The earth must become as it appears: blue and white, not capitalist or Communist; blue and white, not rich or poor; blue and white, not envious or envied. ~Michael Collins, astronaut   I'm looking for a noun or verb that describes this positive enlightening experience. How do I get the Glare node to output transparent instead of Black background I'm a trainee teacher and I need to pass a skills test in maths, but I'm having trouble in this particular area of algebra in finding the nth term of any sequence. I've been given a series of questions to answer one of them is:  Find the nth term of the sequence 3, 8, 15, 24.  I not only need to know the answer but more importantly the technique. This is GCSE level. Find the coefficient of the term $x^2$ in $\left(x+\frac 2x\right)^{4}$ Find the coefficient of the term $x^2$ in $$\left(x+\frac 2x\right)^{4}$$   This is what I have done so far.  We know $a$ = $x$ and $b$ = $\frac2x$ and $n$ = 4  So what I have done is $4c2$ x $(x)^2$ x ($\frac2x$)$^2$  As we know that $^2$ + $^2$ = 4, and 4 is the $n$ value.  The answer is one though?  What have I done wrong?   P.S.  was the tutorial that helped me. I've got the following question:  $A = \{\sqrt{n} - \left\lfloor\sqrt{n}\right\rfloor : n \in \mathbb{N}\}$  Find inf A, sup A    inf A is no big deal, but I have a hard time proving sup A is 1  I've tried to prove that: $\sqrt{n^2 - 1} -\left\lfloor\sqrt{n^2-1}\right\rfloor &gt; \sqrt{n} -\left\lfloor\sqrt{n}\right\rfloor $  but couldn't find a way to do that When should com­pound words be writ­ten as one word, with hy­phens, or with spaces? Using singular "they" for an animal As I know,  (not only &quot;it&quot;). Also, if a person's gender is unknown, . Is it possible to use &quot;they&quot; when we talk about a specific animal and in what context? Proving that the given set has at most $2^{n-1}$ elements Writing a git post-receive hook to deal with a specific branch How to implement draggable tab using Java Swing? How do I implement a draggable tab using Java Swing? Instead of the static JTabbedPane I would like to drag-and-drop a tab to different position to rearrange the tabs.  EDIT: . In fact, of these, only Charcoal shows a recent time stamp. So I wanted to make some minecoins and I also heard that anyone become a marketplace creator could but I don't know where to apply. I'm in Minecraft Pocket Edition 1.14.30. Can you tell me where I can apply? Standard example where Jacobson radical not equal nilradical Types of photon qubit encoding How many types of qubit encoding on photons exist nowadays? I know only two:   Encoding on polarization: $$ \lvert \Psi \rangle = \alpha \lvert H \rangle + \beta \lvert V \rangle $$ $$ \lvert H \rangle = \int_{-\infty}^{\infty} d\mathbf{k}\ f(\mathbf{k}) e^{-iw_k t} \hat{a}^\dagger_{H}(\mathbf{k}) \lvert 0 \rangle_\text{Vacuum} $$ $$ \lvert V \rangle = \int_{-\infty}^{\infty} d\mathbf{k}\ f(\mathbf{k}) e^{-iw_k t} \hat{a}^\dagger_{V}(\mathbf{k}) \lvert 0 \rangle_\text{Vacuum} $$ Time-bin: $$ \lvert \Psi \rangle = \alpha \lvert 0 \rangle + \beta \lvert 1 \rangle $$ $$ \lvert 0 \rangle = \int_{-\infty}^{\infty} dz\ f\left(\frac{t -z/c}{\delta t_{ph}}\right) e^{-i w_0 (t-z/c)} \hat{a}^\dagger(z) \lvert 0 \rangle_\text{Vacuum} $$ $$ \lvert 1 \rangle = \int_{-\infty}^{\infty} dz\ f\left(\frac{t -z/c+\tau}{\delta t_{ph}}\right) e^{-i w_0 (t-z/c+\tau)} \hat{a}^\dagger(z) \lvert 0 \rangle_\text{Vacuum} $$   Is there anything else?