Search Results

Search found 7672 results on 307 pages for 'compiler optimization'.

Page 92/307 | < Previous Page | 88 89 90 91 92 93 94 95 96 97 98 99  | Next Page >

  • How can I Query only __key__ on a Google Appengine PolyModel child?

    - by Gabriel
    So the situation is: I want to optimize my code some for doing counting of records. So I have a parent Model class Base, a PolyModel class Entry, and a child class of Entry Article: How would I query Article.key so I can reduce the query load but only get the Article count. My first thought was to use: q = db.GqlQuery("SELECT __key__ from Article where base = :1", i_base) but it turns out GqlQuery doesn't like that because articles are actually stored in a table called Entry. Would it be possible to Query the class attribute? something like: q = db.GqlQuery("select __key__ from Entry where base = :1 and :2 in class", i_base, 'Article') neither of which work. Turns out the answer is even easier. But I am going to finish this question because I looked everywhere for this. q = db.GqlQuery("select __key__ from Entry where base = :1 and class = :2", i_base, 'Article')

    Read the article

  • How do polymorphic inline caches work with mutable types?

    - by kingkilr
    A polymorphic inline cache works by caching the actual method by the type of the object, in order to avoid the expensive lookup procedures (usually a hashtable lookup). How does one handle the type comparison if the type objects are mutable (i.e. the method might be monkey patched into something different at run time). The one idea I've come up with would be a "class counter" that gets incremented each time a method is adjusted, however this seems like it would be exceptionally expensive in a heavily monkey patched environ since it would kill all the PICs for that class, even if the methods for them weren't altered. I'm sure there must be a good solution to this, as this issue is directly applicable to Javascript and AFAIK all 3 of the big JS VMs have PICs (wow acronym ahoy).

    Read the article

  • Why is doing a top(1) on an indexed column in SQL Server slow?

    - by reinier
    I'm puzzled by the following. I have a DB with around 10 million rows, and (among other indices) on 1 column (campaignid_int) is an index. Now I have 700k rows where the campaignid is indeed 3835 For all these rows, the connectionid is the same. I just want to find out this connectionid. use messaging_db; SELECT TOP (1) connectionid FROM outgoing_messages WITH (NOLOCK) WHERE (campaignid_int = 3835) Now this query takes approx 30 seconds to perform! I (with my small db knowledge) would expect that it would take any of the rows, and return me that connectionid If I test this same query for a campaign which only has 1 entry, it goes really fast. So the index works. How would I tackle this and why does this not work? edit: estimated execution plan: select (0%) - top (0%) - clustered index scan (100%)

    Read the article

  • Avoiding "variable might not have been initialized"

    - by Mason Wheeler
    I recently ran across a routine that looks something like this: procedure TMyForm.DoSomething(list: TList<TMyObject>; const flag: boolean); var local: integer; begin if flag then //do something else local := ExpensiveFunctionCallThatCalculatesSomething; //do something else for i := 0 to list.Count do if flag then //do something else if list[i].IntValue > local then //WARNING HERE //do something else end; This gives Variable 'local' might not have been initialized even though you can tell by reading the code that you won't hit that line unless the code branch that initializes it has run. Now, I could get rid of this warning by adding a useless local := 0; at the top of the procedure, but I wonder if there might not be a better way to structure this to avoid the issue. Anyone have any ideas?

    Read the article

  • Where is this backward_warning.h #warning coming from?

    - by Piku
    Without looking through every single source file in my XCode project, is there a way to find out which #include is triggering the following warning? #warning This file includes at least one deprecated or antiquated header. Please consider using one of the 32 headers found in section 17.4.1.2 of the C++ standard. Examples include substituting the <X> header for the <X.h> header for C++ includes, or <iostream> instead of the deprecated header <iostream.h>. To disable this warning use -Wno-deprecated. Clicking on the error in XCode just opens the backward_warning.h file, which is totally useless. I know what the warning means, I know how to fix it (when I see the file in question and can look at its #includes)... but I just don't know how to find the file causing the error!

    Read the article

  • Is there a faster TList implementation ?

    - by dmauric.mp
    My application makes heavy use of TList, so I was wondering if there are any alternative implementations that are faster or optimized for particular use case. I know of RtlVCLOptimize.pas 2.77, which has optimized implementations of several TList methods. But I'd like to know if there is anything else out there. I also don't require it to be a TList descendant, I just need the TList functionality regardless of how it's implemented. It's entirely possible, given the rather basic functionality TList provides, that there is not much room for improvement, but would still like to verify that, hence this question.

    Read the article

  • In PHP is faster to get a value from an if statement or from an array?

    - by Vittorio Vittori
    Maybe this is a stupid question but what is faster? <?php function getCss1 ($id = 0) { if ($id == 1) { return 'red'; } else if ($id == 2) { return 'yellow'; } else if ($id == 3) { return 'green'; } else if ($id == 4) { return 'blue'; } else if ($id == 5) { return 'orange'; } else { return 'grey'; } } function getCss2 ($id = 0) { $css[] = 'grey'; $css[] = 'red'; $css[] = 'yellow'; $css[] = 'green'; $css[] = 'blue'; $css[] = 'orange'; return $css[$id]; } echo getCss1(3); echo getCss2(3); ?> I suspect is faster the if statement but I prefere to ask!

    Read the article

  • Does the order of columns in a query matter?

    - by James Simpson
    When selecting columns from a MySQL table, is performance affected by the order that you select the columns as compared to their order in the table (not considering indexes that may cover the columns)? For example, you have a table with rows uid, name, bday, and you have the following query. SELECT uid, name, bday FROM table Does MySQL see the following query any differently and thus cause any sort of performance hit? SELECT uid, bday, name FROM table

    Read the article

  • Why is Javascript's Math.floor the slowest way to calculate floor in Javascript?

    - by z5h
    I'm generally not a fan of microbenchmarks. But this one has a very interesting result. http://ernestdelgado.com/archive/benchmark-on-the-floor/ It suggests that Math.floor is the SLOWEST way to calculate floor in Javascript. ~~n, n|n, n&n all being faster. This seems pretty shocking as I would expect that people implementing Javascript in today's modern browsers would be some pretty smart people. Does floor do something important that the other methods fail to do? Is there any reason to use it?

    Read the article

  • Database indexes - what should they be

    - by WebweaverD
    Most of my database tables have a clear unique index through which lookups are done 90% of the time but I am a bit unsure on this one - I have a table which keeps track of user rating totals for items in my database, I now want to add another table, to track individual ratings with an ip address column to make sure no one can rate something twice. Since I can see this becoming a big, high use table it is important to optimize it correctly. (MYSQL table) This table will have the following fields: rating_id(always - unique), item_id (always - not unique), user_id (optional - not unique), ip_address (always - not unique), rating_value(always - not unique), has_review(bool) Now I envisions 90% the queries going something like this: When a user rates something - select where item_id = x and ip_address = y, (if rows = 0) insert rating When in user account pages - select where ip_address = x or username = y Now none of the fields searched on are unique, can I still use them as indexes (for example item _id and ip_address), can I have two indexes and will this still improve performance over a non indexed table?

    Read the article

  • Completely remove ViewState for specific pages

    - by Kerido
    Hi everybody, I have a site that features some pages which do not require any post-back functionality. They simply display static HTML and don't even have any associated code. However, since the Master Page has a <form runat="server"> tag which wraps all ContentPlaceHolders, the resulting HTML always contains the ViewState field, i.e: <input type="hidden" id="__VIEWSTATE" value="/wEPDwUKMjEwNDQyMTMxM2Rk0XhpfvawD3g+fsmZqmeRoPnb9kI=" /> I realize, that when decrypted, this string corresponds to the <form> tag which I cannot remove. However, I would still like to remove the ViewState field for pages that only display static HTML. Is it possible?

    Read the article

  • SEO Google - Navigation Title vs. Page Heading

    - by louism
    Hi, i was wondering if anyone knows if theres a connection between what a navigation item is named and the page heading it goes to - does this have an impact on SEO? so for example, if i had in my navigation menu an item called About Us, but when you click it you come to a page with the heading Learn Who We Are (i.e. wrapped in [h1] heading tags) because there isnt an exact one-to-one match, is that a bad thing in terms of SEO? thanks

    Read the article

  • Splitting tables by field to optimize MySQL?

    - by AK
    Do splitting fields into multiple tables ever yield faster queries? Consider the following two scenarios: Table1 ----------- int PersonID text Value1 float Value2 or Table1 ----------- int PersonID text Value1 Table2 ----------- int PersonID float Value2 If Value1 and Value2 are always being displayed together, I imagine Table1 is always faster because the second schema would require two SELECT statements. But are there any situations where you would choose the second? If the number of records were expected to be really large?

    Read the article

  • How do you set up your JScript (NOT JScript.NET) development environment?

    - by jJack
    In my environment, if I create a class in JScript syntax: class test{ } and then save it to a file named "test.js" and run it with wscript, I get a Microsoft JScript "Syntax error" at line 1. However, if I simply, say, write a function: function getInput() { var wshell = WScript.CreateObject("WScript.Shell"); wshell.Popup ("Do you want to continue?"); return userInput } getInput() and run it the same way, it works. Hopefully, there is something fundamentally wrong with my class definition. If that is the case, I am excited to find out.

    Read the article

  • Script Speed vs Memory Usage

    - by Doug Neiner
    I am working on an image generation script in PHP and have gotten it working two ways. One way is slow but uses a limited amount of memory, the second is much faster, but uses 6x the memory . There is no leakage in either script (as far as I can tell). In a limited benchmark, here is how they performed: -------------------------------------------- METHOD | TOTAL TIME | PEAK MEMORY | IMAGES -------------------------------------------- One | 65.626 | 540,036 | 200 Two | 20.207 | 3,269,600 | 200 -------------------------------------------- And here is the average of the previous numbers (if you don't want to do your own math): -------------------------------------------- METHOD | TOTAL TIME | PEAK MEMORY | IMAGES -------------------------------------------- One | 0.328 | 540,036 | 1 Two | 0.101 | 3,269,600 | 1 -------------------------------------------- Which method should I use and why? I anticipate this being used by a high volume of users, with each user making 10-20 requests to this script during a normal visit. I am leaning toward the faster method because though it uses more memory, it is for a 1/3 of the time and would reduce the number of concurrent requests.

    Read the article

  • Avoid the use of loops (for) with R

    - by albergali
    Hi, I'm working with R and I have a code like this: i<-1 j<-1 for (i in 1:10) for (j in 1:100) if (data[i] == paths[j,1]) cluster[i,4] <- paths[j,2] where : data is a vector with 100 rows and 1 column paths is a matrix with 100 rows and 5 columns cluster is a matrix with 100 rows and 5 columns My question is: how could I avoid the use of "for" loops to iterate through the matrix? I don't know whether apply functions (lapply, tapply...) are useful in this case. This is a problem when j=10000 for example, because execution time is very long. Thank you

    Read the article

  • What information about me and my system do compilers add to executeables?

    - by I can't tell you my name.
    I'm currently using Microsoft Visual Studio 2010. If we say that we give 10 different people a copy of MSVC 10 and a short C++ Hello, World listing. They all create a new project using exactly the same settings, add a new cpp file with the Hello, World program and compile it. Do they all get the exactly same binary? If not, what are the exact differences? What information about my system does MSVC add to my executeable? Paranoia!

    Read the article

  • Unicorn: Which number of worker processes to use?

    - by blackbird07
    I am running a Ruby on Rails app on a virtual Linux server that is capped at 1GB RAM. Currently, I am constantly hitting the limit and would like to optimize memory utilization. One option I am looking at is reducing the number of unicorn workers. So what is the best way to determine the number of unicorn workers to use? The current setting is 10 workers, but the maximum number of requests per second I have seen on Google Analytics Real-Time is 3 (only scored once at a peak time; in 99% of the time not going above 1 request per second). So is it a save assumption that I can - for now - go with 4 workers, leaving room for unexpected amounts of requests? What are the metrics I should have a look at for determining the number of workers and what are the tools I can use for that on my Ubuntu machine?

    Read the article

  • Nginx , Apache , Mysql , Memcache with server 4G ram. How optimize to enoigh of memory?

    - by TomSawyer
    i have 1 dedicated server with Nginx proxy for Apache. Memcache, mysql, 4G Ram. These day, my visitor on my site wasn't increased, but my server get overload always in some specified time. (9AM - 15PM) Ram in use is increased second by second to full. that's moment, my server will get overload. i have to kill all apache , mysql service and reboot it to get free memory. and it'll full again. that's the terrible circle. here is my ram in use at the moment 160(nginx) 220(apache) 512(memcache) 924(mysql) here's process number 4(nginx) 14(apache) 5(memcache) 20(mysql) and here's my my.cnf config. someone can help me to optimize it? [mysqld] datadir=/var/lib/mysql socket=/var/lib/mysql/mysql.sock user=mysql skip-locking skip-networking skip-name-resolve # enable log-slow-queries log-slow-queries = /var/log/mysql-slow-queries.log long_query_time=3 max_connections=200 wait_timeout=64 connect_timeout = 10 interactive_timeout = 25 thread_stack = 512K max_allowed_packet=16M table_cache=1500 read_buffer_size=4M join_buffer_size=4M sort_buffer_size=4M read_rnd_buffer_size = 4M max_heap_table_size=256M tmp_table_size=256M thread_cache=256 query_cache_type=1 query_cache_limit=4M query_cache_size=16M thread_concurrency=8 myisam_sort_buffer_size=128M # Disabling symbolic-links is recommended to prevent assorted security risks symbolic-links=0 [mysqldump] quick max_allowed_packet=16M [mysql] no-auto-rehash [isamchk] key_buffer=256M sort_buffer=256M read_buffer=64M write_buffer=64M [myisamchk] key_buffer=256M sort_buffer=256M read_buffer=64M write_buffer=64M [mysqlhotcopy] interactive-timeout [mysql.server] user=mysql basedir=/var/lib [mysqld_safe] log-error=/var/log/mysqld.log pid-file=/var/run/mysqld/mysqld.pid

    Read the article

  • Compiling a class using Java code using process

    - by Noona
    I have this piece of code that compiles a class called tspClassName, when I compile using this code: Process compileProc = null; try { compileProc = Runtime.getRuntime().exec("javac -classpath ." + File.separator + "src" + File.separator + File.separator + "generated." + tspClassName + ".java -d ." + File.separator + "bin"); // catch exception if (compileProc.exitValue() != 0) { System.out.println("Compile exit status: " + compileProc.exitValue()); System.err.println("Compile error:" + compileProc.getErrorStream()); it outputs this: "Compile exit status: 2 Compile error:java.io.FileInputStream@17182c1" The class tspClassName.java compiles without errors otherwise, so I am guessing it has to do with the path,and in my eclipse project, the tspClassName.java resides in package homework4.generated inside src, is there something wrong with the path that I use in the code? thanks

    Read the article

  • Invalid instruction suffix for push when assembling with gas

    - by vitaut
    When assembling a file with GNU assembler I get the following error: hello.s:6: Error: invalid instruction suffix for `push' Here's the file that I'm trying to assemble: .text LC0: .ascii "Hello, world!\12\0" .globl _main _main: pushl %ebp movl %esp, %ebp subl $8, %esp andl $-16, %esp movl $0, %eax movl %eax, -4(%ebp) movl -4(%ebp), %eax call __alloca call ___main movl $LC0, (%esp) call _printf movl $0, %eax leave ret What is wrong here and how do I fix it?

    Read the article

  • Visual Studio 2005 Error

    - by xscape
    Im currently debugging a webservice written in visual studio 2005, however when i build it, it has an error but it did not specify anything Error 1 The specified module could not be found. (Exception from HRESULT: 0x8007007E) error message can be seen here Badly needed your help. Thank you

    Read the article

  • MySQL Paritioning performance

    - by Imran Pathan
    Measured performance on key partitioned tables and normal tables separately. But we couldn't find any performance improvement with partitioning. Queries are pruned. Using MySQL 5.1.47 on RHEL 4. Table details: UserUsage - Will have entries for user mobile number and data usage for each date. Mobile number and Date as PRI KEY. UserProfile - Queries prev table and stores summary for each mobile number. Mobile number PRI KEY. CREATE TABLE `UserUsage` ( `Msisdn` decimal(20,0) NOT NULL, `Date` date NOT NULL, . . PRIMARY KEY USING BTREE (`Msisdn`,`Date`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 PARTITION BY KEY(Msisdn) PARTITIONS 50; CREATE TABLE `UserProfile` ( `Msisdn` decimal(20,0) NOT NULL, . . PRIMARY KEY (`Msisdn`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 PARTITION BY KEY(Msisdn) PARTITIONS 50; Second table is updated by query select and order by date in first table in a perl program, query is select * from UserUsage where Msisdn=number order by Date desc limit 7 [Process data in perl] update UserProfile values(....) where Msisdn=number explain partition for select, shows row being scanned in a particular partition only. Is something wrong with partition design or queries as partitioning is taking almost same or more time compared to normal tables?

    Read the article

  • Should Python import statements always be at the top of a module?

    - by Adam J. Forster
    PEP 08 states: Imports are always put at the top of the file, just after any module comments and docstrings, and before module globals and constants. However if the class/method/function that I am importing is only used in rare cases, surely it is more efficient to do the import when it is needed? Isn't this: class SomeClass(object): def not_often_called(self) from datetime import datetime self.datetime = datetime.now() more efficient than this? from datetime import datetime class SomeClass(object): def not_often_called(self) self.datetime = datetime.now()

    Read the article

  • Getting following warning while compiling

    - by thetna
    warning: passing argument 1 of 'bsearch' makes pointer from integer without a cast and the corresponding code is Parent =bsearch((const size_t)ParentNum, ClauseVector, Size, sizeof(CLAUSE),pcheck_CompareNumberAndClause); the compilar is gcc. here CLAUSE is defined as *CLAUSE.

    Read the article

< Previous Page | 88 89 90 91 92 93 94 95 96 97 98 99  | Next Page >