Good optimization for Mysql
Can you help me with my capacity planning?
Open a window on a remote X display (why "Cannot open display")? Once upon a time,  DISPLAY=:0.0 totem /path/to/movie.avi   after ssh 'ing into my desktop from my laptop would cause totem to play movie.avi on my desktop.  Now it gives the error:   No protocol specified Cannot open display:    I reinstalled Debian squeeze when it went stable on both computers, and I guess I broke the config.   I've googled on this, and cannot for the life of me figure out what I'm supposed to be doing.   (VLC has an HTTP interface that works, but it isn't as convenient as ssh.)  The same problem arises when I try to run this from a cron job. Height and minimal number of generators of an ideal How can I determine the height and the least number of generators of the ideal $ I=(xz-y^2,x^3-yz,z^2-x^2y) \subset K[x,y,z] $?      I tried to calculate the dimension of the vector space $I/I\mathfrak m$ with $\mathfrak m=(x,y,z)$, but I'm not able to find it.  I think the height is $2$, because the affine variety should be a curve, and also I know that the ideal is prime, so I need a chain $0\subset \mathfrak p \subset I$. Maybe $(xz-y^2)?$ Is it prime? Use masks as part of materials in cycles Can I successfully bake previously-frozen bread dough? I prefer my bread freshly baked (who doesn't?), but my mixer prefers kneading two loaves at a time to just kneading one. I have tried to freeze the second loaf before baking it, but when I thaw it, it does not rise well before baking. I've tried thawing it entirely in the refrigerator and then letting it rise on the counter, but that did not seem to work. Does anyone have a good technique or suggestion for this? Wouldn't the thermodynamic cost of creating alternate universes make the Many Worlds interpretation implausible? "DataBinding: 'index+NewsItem' does not contain a property with the name 'Link'", but property exists (Not a Typo) In an Integral Domain is it true that $\gcd(ac,ab) = a\gcd(c,b)$? The first and (the) second chapter(s) are difficult - which is correct? I'm a little confused about the following sentences. Could you please tell me which one(s) is/are correct?        The first and the second chapter are difficult.   The first and the second chapters are difficult.   The first and second chapters are difficult.   The first and second chapter are difficult.      I believe #1 &amp; #3 are correct, while #2 &amp; #4 are incorrect.  But when seeing the answers to the Quora question , I wonder why they say #2 is correct. How to "grep" for line length in a given range? Is "double hashing" a password less secure than just hashing it once? Is hashing a password twice before storage any more or less secure than just hashing it once?  What I'm talking about is doing this:  $hashed_password = hash(hash($plaintext_password));   instead of just this:  $hashed_password = hash($plaintext_password);   If it is less secure, can you provide a good explanation (or a link to one)?  Also, does the hash function used make a difference?  Does it make any difference if you mix md5 and sha1 (for example) instead of repeating the same hash function?  Note 1:  When I say "double hashing" I'm talking about hashing a password twice in an attempt to make it more obscured.  I'm not talking about the .  Note 2:  I know I need to add a random salt to really make it secure.  The question is whether hashing twice with the same algorithm helps or hurts the hash. LIGO has announced the detection of gravitational waves on 11 Feb, 2016. I was wondering why the detection of gravitational waves was so significant?   I know it is another confirmation of general relativity (GR), but I thought we had already confirmed GR beyond much doubt. What extra stuff would finding gravitational waves teach us? Is the detection of gravitational waves significant in and of itself, or is there data which can be extracted from the waves which will be more useful? How to force nginx to resolve DNS (of a dynamic hostname) everytime when doing proxy_pass? My passport is expiring; can I still travel? Want to cancel a 'Pending Erase' on iphone... Any suggestions? I lost my phone on vacation and activated 'Lost Mode' for a couple of days. The night before heading home I decided to do the Remote Erase ´cause I thought there's no way I'd get it back, I also called my carrier and canceled the data service on my number. The phone has been offline ever since but the hotel just called to say they found my phone at the spa and they are mailing it back to me. So I want to cancel the 'Pending Erase', all I care about is recovering all the pictures from that trip that I hadn't backed up on iCloud yet... Will removing the device from my iCloud account work?  And if I don't have service on the phone, will the 'Erase iPhone' command still go through when I turn it on?  Please help! I have two days to figure this out What happens 'internally' on a unstable/overclocked/undervolted CPU? When you undervolt or overlock an CPU, when it passes a certain limit it starts to make the system unstable, reboot, etc. But these are the effects of it.  What I'm curious about is what happens on the CPU. What happens? It gives wrong answers to instructions? Bits on cache flip? I'm a citizen of an EU member state traveling to a small city in Vermont. Looking at flight data, it seems that it would be quite a bit quicker to fly into Montreal (Canada) and then drive a rental car to my final destination in Vermont (and back), rather than getting a connecting flight into a small local US airport. I am slightly worried about the trouble I might get myself into by crossing a land border twice, though.  Can anyone give me an idea of what I'd be getting into in terms of:   Crossing time Discomfort Additional paperwork required   For both the outbound (Canada/US) and the return leg (US/Canada) of my journey, when compared to crossing the border at an international airport?  Also, do I need to take any special actions when I'm arranging a rental car if I intend to drive it over to the US and back? How to block sites with iptables TSA requirements regarding ID If the name on my boarding pass lists Debbie and my Drivers License lists Debra, will this be a problem? When can I be sure a questionable check has cleared? I have the following recurrence that I've been pounding on:  $$ a(0)=1\\ a(1)=1\\ a(2)=2\\ a(2n)=a(n)+a(n+1)+n\ \ \ (\forall n&gt;1)\\ a(2n+1)=a(n)+a(n-1)+1\ \ \ (\forall n\ge 1) $$  I don't have much background in solving these things, so I've been googling around looking for different techniques. Unfortunately, I haven't been able to correctly apply them yet. So far I've tried:   Characteristic equations Generating functions Plugging it into Wolfram Alpha Telescoping Observation   I'm sure that one or more of these is the way to go, but my biggest problem right now is figuring out how to deal with the idea that there are different equations for odd and even values of $n$. I'm not necessarily looking for a solution (though it would be gratefully accepted), but any nudges in the right direction would be much appreciated.    To follow up, it turned out that the speed problem described in my comment, below was related to the Decimal implementation in Python 2.7. Switching to Python 3.3 (and Java) made everything many orders of magnitude better.