The Big Programming Thread - Page 583

On February 09 2015 13:22 travis wrote:
java question

If I pass a reference to another instance as an argument, can I make it so that all of the methods in the new instance will recognize the fields in that reference? like for example a string in the original instance, I can print it from within the constructor of the new instance, but if I try to print it from a method that is called in that constructor, it won't work unless I pass it on as a parameter to that method as well. but that seems really redundant if I am going to be using a bunch of methods... having to put the reference as a parameter over and over. does anyone understand what I am talking about?

On February 09 2015 17:43 Morfildur wrote:


A year ago we tried to implement couchbase at work to replace some MySQL user-relationship table. It worked perfectly in simulation but instantly broke down under live load when it got 1000 write requests per second. We switched it back to MySQL fast. Since then, couchbase is a forbidden word

On February 09 2015 13:50 travis wrote:

class1{ String mystring="blah" }

class2 { 
class1 x = new class1
class3 y = new class3(x)}

class3{

class3(class1 thing){
System.out.print(thing.mystring);
method();
}

method(){
System.out.print(thing.mystring);
}}

hopefully the code is good here. I made it as simple as possible.
in this example I believe that mystring would print out as "blah" the first time, but the 2nd time method will not see thing anymore. so it won't print out mystring, it would just have an error. I am wondering if there is an easy way to make method and any other methods in class3 to see thing.

class3{
class1 thing;

class3(class1 thing){
System.out.print(thing.mystring);
this.thing = thing;
method();
}

method(){
System.out.print(thing.mystring);
}}

On February 09 2015 20:48 Djagulingu wrote:

Is it that bad? I mean, all those benchmarks and shit say that couchbase is much much better than mongo and cassandra when the number of client threads go up to 4 digits. I didn't stress*test it myself though.

On February 10 2015 04:46 SpiZe wrote:
Anyone here has experience with SSL certificates ?

I have a database with 430k entries of PEM encoded certificates, that I need to decode and store back into another DB with a more logical structure (issuer, encrytion algorithm, start date, end date and so on). I can decode .crt file into text then I can parse through that text to find the info the I need. However, since I need to create .crt files to read them and then parse the result and store it in my database.... this seems terribly inefficient.

I'm inexperienced with both SSL certificates and data sets of that size so I don't even really know where am I going to be honest. If anyone has a vague idea, I'm not looking for a step by step, just some random thoughts if you have any.

On February 08 2015 18:08 nunez wrote:
help please.

i need a word with the following meaning:
a statement that is not an expression.
all i got is: NonExpression... NExpression... Nexpression...

for now i'm going with Nexpression.

On February 10 2015 02:50 Morfildur wrote:


That's just 1650 requests a second and most likely most of them are read-only, though the actual use case wasn't explained. It's so easy to make numbers sound big and impressive when most you are doing is sending out the same webpage out again and again from a cache.

On February 10 2015 15:05 teamamerica wrote:
Hey all - I barely code Java so this is probably old news but I was looking at some java collections extensions - so nice to use~ It's like my python (no comprehensions but I'll survive) + autocompleting since static types. Plus there are some fun exercises they give to expose it. I was looking specifically at goldman-sachs collections but I guess there's also Guava (with a whole lot more then just collections) and fastuil as some others.

The gs collections api (from my 2 minute of using it) just seems so nice to use...

Also frustrations from work = everyone using hashmap in multithreaded environment = infinite loop = sadness

On February 12 2015 21:58 Morfildur wrote:
I have an interesting problem that I'm trying to think through:

At work we need a realtime scheduling system where events can be scheduled to happen e.g. 5 seconds from now or theoretically 5 month, 4 days, 3 hours, 2 minutes and 1 second from now, though most events are scheduled for at most a week in the future. The number of scheduled events potentially numbers in the 1000s for every single second, i.e. a span of 10 seconds can have a total of 50000+ scheduled events. Past events have to be processed as long as they aren't past their TTL, i.e. when the schedule misses 10s due to a restart or hiccup, all those events still have to get processed.

Until recently we used a database with a "update X set processed=workerid where processed is null" statement that the ~100 worker processes executed whenever they ran out of jobs. It was far too slow eventhough a garbage collector held the table as small as possible by removing all finished events. We then switched to a Redis based solution, which can handle it but occasionally runs into performance issues as well.

I've now decided that it would be a nice problem to use to get back into C++, so I've started developing a C++ service that takes care of the scheduling. I'm just thinking about how to store the data internally so it is efficient for those large numbers of events. The service just has 2 functions: ScheduleEvent and GetNextEvent. ScheduleEvent adds an event at any point in time, GetNextEvent returns the next scheduled event based on time, variable time-to-live and event priority

I'm currently using a std::map<int, std::vector<Item>*> with the map key being the timestamp and the vector containing the items, but I'm having trouble with the time it takes to seek through the vectors, especially after the workers stopped processing for a few seconds and many events went past their TTL.

On February 13 2015 00:12 Manit0u wrote:
I wonder if it would be possible to use fcron for that...