Search Results

Search found 7551 results on 303 pages for 'pre optimization'.

Page 54/303 | < Previous Page | 50 51 52 53 54 55 56 57 58 59 60 61  | Next Page >

• Speeding up ROW_NUMBER in SQL Server

  - by BlueRaja

  We have a number of machines which record data into a database at sporadic intervals. For each record, I'd like to obtain the time period between this recording and the previous recording. I can do this using ROW_NUMBER as follows: WITH TempTable AS ( SELECT *, ROW_NUMBER() OVER (PARTITION BY Machine_ID ORDER BY Date_Time) AS Ordering FROM dbo.DataTable ) SELECT [Current].*, Previous.Date_Time AS PreviousDateTime FROM TempTable AS [Current] INNER JOIN TempTable AS Previous ON [Current].Machine_ID = Previous.Machine_ID AND Previous.Ordering = [Current].Ordering + 1 The problem is, it goes really slow (several minutes on a table with about 10k entries) - I tried creating separate indicies on Machine_ID and Date_Time, and a single joined-index, but nothing helps. Is there anyway to rewrite this query to go faster?

  Read the article

• MySQL too many connections

  - by Webnet

  On my server I have 7 databases. Our server has 512 MB of RAM which I'm getting upgraded this evening to 2GB and has a 2.4 single processor. I've gotten an error about the connection limit exceeded. With increasing my RAM, is it ok to increase the number of connections? Currently it's set to 200 but a single page may connect to 3-4 databases considering JOINs and things. We've setup so many databases for mere organization. We have a total of about 250-300 tables in all of the databases. Any advice would be appreciated :)

  Read the article

• Optimizing memory usage across multiple similar VMs

  - by zildjohn01

  Let's say I have four VM's open, each running an identical version of Windows. Under my current setup, the guest OS will be loaded into memory four times. Much of that is wasted space. Using any VM host on the market, is there any way to consolidate that memory usage?

  Read the article

• Utility to optimally distribute files onto multiple DVDs?

  - by Alex R

  I have a bunch of media files which I want to record to DVD, but since each DVD only fits 4.5GB, I have to find the optimal way to organize the files to use the minimum number of DVDs (otherwise the empty space left in each DVD can easily add up). Are there any tools to help with this? Many years ago there was a DOS utility to do this with floppy disks.

  Read the article

• How to determine the best byte size for the dd command

  - by James

  I know that doing a dd if=/dev/hda of=/dev/hdb does a deep hard drive copy. I've heard that people have been able to speed up the process by increasing the number of bytes that are read and written at a time (512) with the "bs" option. People have suggested that the optimal byte size is due to sector size. I personally think it would have something to do with the amount of cache that the hard drive has. My question is: What determines the ideal byte size for copying from a hard drive? and Why does that determine the ideal byte size?

  Read the article

• Using different SSDs types (not only SATA based) as system drive

  - by Hubert Kario

  Currently I have a Thinkpad X61s and want to make it both a bit faster and a bit more power efficient. For that reason I thought that adding SSD drive would make most sense. Unfortunately, because of financial reasons, buying SSD of over 200GB capacity is out of reach for me (not only it would be worth more than the rest of the laptop, but also I currently have a 500GB drive in it, so even such a drive would be kind of a downgrade for me). During preliminary testing with a cheap Transcend 4GB Class 6 (14MiB/s streaming, 9MiB/s random read) card I experienced boot times to be reduced by half so putting the OS only on it would already would be an improvement. Unfortunately, my system now is about 11GiB in size so anything less than 16GB would be constraining. In this laptop I can connect additional drives on at least 5 different ways: using SATA-ATA converter caddy in the X6 Ultrabase using internal mini PCIe slot using integrated SDHC slot using CardBus (a.k.a PCMCIA or PC Card) slot using USB Thankfully, because I use only Linux on this PC the bootability of them is irrelevant as I can put the /boot partition on internal HDD and / on any of the above mentioned Flash memories (as I already did for the SDHC test). From what I was able to research and from my own experience those options come with rather big downsides or other problems: SATA-ATA caddy It has three downsides: I have to carry the Ultrabse with me at all times (it's not really inconvenient, but those grams do add) and couldn't disconnect it when I want to disconnect the battery It makes the bay unusable for the optical drive and occasional quick access to other hard drives the only caddies I could buy have rather flaky controllers in them so putting my OS on it would hamper its stability Internal mini PCIe slot This would be an ideal solution, if only I could find real PCIe SSDs, not only devices that could talk only SATA or ATA over PCIe mechanical connection (the ones used in Dell Mini or Asus EEE). Theoretically Samsung did release such devices but I couldn't find them in retail anywhere. Integrated SDHC slot It's a nice solution with a single drawback: the fastest 16GB SDHC card on the market can only do around 35MiB/s read and 15MiB/s write while still costing like a normal 40GB SATA SSD that's 10 times faster. Not really cost-effective. CardBus (a.k.a PCMCIA or PC Card) slot Those cards are much faster than the SDHC option (there are ones that can do well over 50MiB/s read in benchmarks) and from what I could find the PCMCIA controller in my laptop does support UDMA so it should be able to deliver comparable speeds. They still cost similarly to SD cards but at least they provide streaming performance comparable to my current HDD. USB That's the worst option. Not only is it limited to 20-30MiB/s by the interface itself the drive would stick out of the laptop so it's a big no no. The question As such I think that going the "CF in a CardBus adapter" route will be the best option. My question is: did anyone try using CF cards in CardBus adapters as system drives with Linux on Thinkpad laptops? Laptops in general? What was the real-world performance? I don't have any CF cards so I can't check how well does it work with suspend/resume, or whatever it's easy to make it work in initramfs (I'm using ArchLinux and SD card was trivial — add 3 modules in single config line and rebuilding initramfs) so any tips/gotchas on this are welcome as well.

  Read the article

• How to get the best LINPACK result and conquer the Top500?

  - by knweiss

  Given a large Linux HPC cluster with hundreds/thousands of nodes. What are your best practices to get the best possible LINPACK benchmark (HPL) result to submit for the Top500 supercomputer list? To give you an idea what kind of answers I would appreciate here are some sub-questions (with links): How to you tune the parameters (N, NB, P, Q, memory-alignment, etc) for the HPL.dat file (without spending too much time trying each possible permutation - esp with large problem sizes N)? Are there any Top500 submission rules to be aware of? What is allowed, what isn't? Which MPI product, which version? Does it make a difference? Any special host order in your MPI machine file? Do you use CPU pinning? How to you configure your interconnect? Which interconnect? Which BLAS package do you use for which CPU model? (Intel MKL, AMD ACML, GotoBLAS2, etc.) How do you prepare for the big run (on all nodes)? Start with small runs on a subset of nodes and then scale up? Is it really necessary to run LINPACK with a big run on all of the nodes (or is extrapolation allowed)? How do you optimize for the latest Intel/AMD CPUs? Hyperthreading? NUMA? Is it worth it to recompile the software stack or do you use precompiled binaries? Which settings? Which compiler optimizations, which compiler? (What about profile-based compilation?) How to get the best result given only a limited amount of time to do the benchmark run? (You can block a huge cluster forever) How do you prepare the individual nodes (stopping system daemons, freeing memory, etc)? How do you deal with hardware faults (ruining a huge run)? Are there any must-read documents or websites about this topic? E.g. I would love to hear about some background stories of some of the current Top500 systems and how they did their LINPACK benchmark. I deliberately don't want to mention concrete hardware details or discuss hardware recommendations because I don't want to limit the answers. However, feel free to mention hints e.g. for specific CPU models.

  Read the article

• How do you set the timezone in a non-standard Linux distro?

  - by Jamie

  I'm trying to set the time in an embedded system ... There isn't a link/file /etc/localtime and /usr/ has only two subdirectories /usr/bin and /usr/sbin. Is there something I can try or do I just give up and make UTC be my timezone?

  Read the article

• Serving images from another hostname vs Apache overload for the rewrites

  - by luison

  We are trying to improve further the speed of some sites with older HTML in order as well to obtain better SEO results. We have now applied some minify measures, combined html, css etc. We use a small virtualized infrastructure and we've always wanted to use a light + standar http server configuration so the first one can serve images and static contents vs the other one php, rewrites, etc. We can easily do that now with a VM using the same files and conf of vhosts (bind mounts) on apache but with hardly any modules loaded. This means the light httpd will have smaller fingerprint that would allow us to serve more and quicker, have more minSpareServer running, etc. So, as browsers benefit from loading static content from different hostnames as well, we've thought about building a rewrite rule on our main server (main.com) to "redirect" all images and css *.jpg, *.gif, *.css etc to the same at say cdn.main.com thus the browser being able to have more connections. The question is, assuming we have a very complex rewrite ruleset already (we manually manipulate many old URLs for SEO) will it be worth? I mean will the additional load of main's apache to have to redirect main.com/image.jpg (I understand we'll have to do a 301) to cdn.main.com/image.jpg + then cdn.main.com having to serve it, be larger than the gain we would be archiving on the browser? Could the excess of 301s of all images on a page be penalized by google? How do large companies work this out, does the original code already include images linked from the cdn with absolute paths?

  Read the article

• Prefork or Worker MPM for amazon xlarge server?

  - by Netismine

  I'm trying to measure would it be better to have prefork or worker mpm apache module for the server I'm working on, which is Amazon X-Large 15 GB memory 8 EC2 Compute Units (4 virtual cores with 2 EC2 Compute Units each) and that will run a Magento website with about 50 active users at once. Site serves a lot of images and about 45 requests per page. Images sometimes hang, so it seems worker would be a better option? Thanks

  Read the article

• Is ext4 more expensive than ntfs?

  - by ???

  I have just converted an NTFS partition to ext4, however the total space seems reduced from 421G to 415G. Where did the 6G go? And, the reserved space is grown to 199M in ext4, much larger compared to 78M in NTFS, why? The partition is mainly used for movies/musics, so most files are very large (10M each). I want to use ext4 file system, is there any suggestion? mkfs.ntfs: /dev/sdb4 421G 78M 421G 1% /mnt/mmedia mkfs.ext4: /dev/sdb4 415G 199M 393G 1% /mnt/mmedia It's also weired that the remaining size of ext4 is 393G, shouldn't it be 415G or 414G? What happened to the disappeared 22G? Compared to NTFS, ext4 seems eaten 28G in total.

  Read the article

• Is there a way to sharpen low quality images

  - by Saif Bechan

  I have a lot of images for a project that are not really sharp and crisp. I think these were old images that were resized a lot etc. This is because I am working on a website for a client and she does not have the high quality pictures anymore, the pictures I have to work with are somewhat pixelated. Ill show you an example of one I think could be better: Now as you can see the parts around the text 'Azule' is not so sharp. Is there a way to sharpen this. Now I have another one, and I think there is no hope for this one. Is there any hope for the picture above to make it sharp again, I highly doubt it.

  Read the article

• how to optimize apache on web-server

  - by Prakash

  how can I optimize the server with following configuration. It takes too much time to load a page. IBM X3200 M3 Server - 1 Intel Xeon Processor with 4 GB Ram Below is my current configuration for apache: Start Servers: 5 (Default) Minimum Spare Servers: 10 Maximum Spare Servers: 20 Server Limit: 500 Max Clients: 500 Max Requests Per Child: 10000 (Default) Keep-Alive: On Keep-Alive Timeout: 5 Max Keep-Alive Requests: 100 Timeout: 200

  Read the article

• Lots of files being used by blank web page. What are they?

  - by byronyasgur

  I am trying to optimise a website and I was using the network waterfall facility in Google Chrome. When I looked at the results there were lots of files which I didnt recognise. I first thought they might be something to do with Google Chrome itself, so I put a blank HTML file on my desktop and checked but there was nothing in the waterfall except the file itself. So I put a blank file on my server and I got the output below. What are all these files, are they all necessary, is this normal and do I need to be in any way concerned. My hosting provider has always been excellent in every regard that I'm aware of. My host is shared hosting, using cpanel and is based on a LAMP server. I also note that a couple of those file have problems but I have no idea how to fault find that or whether it's a concern. EDIT: I have cleared the cache so I don't think it's a browser cache issue.

  Read the article

• How to optimize a postgreSQL server for a "write once, read many"-type infrastructure ?

  - by mhu

  Greetings, I am working on a piece of software that logs entries (and related tagging) in a PostgreSQL database for storage and retrieval. We never update any data once it has been inserted; we might remove it when the entry gets too old, but this is done at most once a day. Stored entries can be retrieved by users. The insertion of new entries can happen rather fast and regularly, thus the database will commonly hold several millions elements. The tables used are pretty simple : one table for ids, raw content and insertion date; and one table storing tags and their values associated to an id. User search mostly concern tags values, so SELECTs usually consist of JOIN queries on ids on the two tables. To sum it up : 2 tables Lots of INSERT no UPDATE some DELETE, once a day at most some user-generated SELECT with JOIN huge data set What would an optimal server configuration (software and hardware, I assume for example that RAID10 could help) be for my PostgreSQL server, given these requirements ? By optimal, I mean one that allows SELECT queries taking a reasonably little amount of time. I can provide more information about the current setup (like tables, indexes ...) if needed.

  Read the article

• MysqlTunner and query_cache_size dilemma

  - by wbad

  On a busy mysql server MySQLTuner 1.2.0 always recommends to add query_cache_size no matter how I increase the value (I tried up to 512MB). On the other hand it warns that : Increasing the query_cache size over 128M may reduce performance Here are the last results: >> MySQLTuner 1.2.0 - Major Hayden <[email protected]> >> Bug reports, feature requests, and downloads at http://mysqltuner.com/ >> Run with '--help' for additional options and output filtering -------- General Statistics -------------------------------------------------- [--] Skipped version check for MySQLTuner script [OK] Currently running supported MySQL version 5.5.25-1~dotdeb.0-log [OK] Operating on 64-bit architecture -------- Storage Engine Statistics ------------------------------------------- [--] Status: +Archive -BDB -Federated +InnoDB -ISAM -NDBCluster [--] Data in InnoDB tables: 6G (Tables: 195) [--] Data in PERFORMANCE_SCHEMA tables: 0B (Tables: 17) [!!] Total fragmented tables: 51 -------- Security Recommendations ------------------------------------------- [OK] All database users have passwords assigned -------- Performance Metrics ------------------------------------------------- [--] Up for: 1d 19h 17m 8s (254M q [1K qps], 5M conn, TX: 139B, RX: 32B) [--] Reads / Writes: 89% / 11% [--] Total buffers: 24.2G global + 92.2M per thread (1200 max threads) [!!] Maximum possible memory usage: 132.2G (139% of installed RAM) [OK] Slow queries: 0% (2K/254M) [OK] Highest usage of available connections: 32% (391/1200) [OK] Key buffer size / total MyISAM indexes: 128.0M/92.0K [OK] Key buffer hit rate: 100.0% (8B cached / 0 reads) [OK] Query cache efficiency: 79.9% (181M cached / 226M selects) [!!] Query cache prunes per day: 1033203 [OK] Sorts requiring temporary tables: 0% (341 temp sorts / 4M sorts) [OK] Temporary tables created on disk: 14% (760K on disk / 5M total) [OK] Thread cache hit rate: 99% (676 created / 5M connections) [OK] Table cache hit rate: 22% (1K open / 8K opened) [OK] Open file limit used: 0% (49/13K) [OK] Table locks acquired immediately: 99% (64M immediate / 64M locks) [OK] InnoDB data size / buffer pool: 6.1G/19.5G -------- Recommendations ----------------------------------------------------- General recommendations: Run OPTIMIZE TABLE to defragment tables for better performance Reduce your overall MySQL memory footprint for system stability Increasing the query_cache size over 128M may reduce performance Variables to adjust: *** MySQL's maximum memory usage is dangerously high *** *** Add RAM before increasing MySQL buffer variables *** query_cache_size (> 192M) [see warning above] The server has 76GB ram and dual E5-2650. The load is usually below 2. I appreciate your hints to interpret the recommendation and optimize the database configs.

  Read the article

• AB failed requests - What can I do about them?

  - by matthewsteiner

  So, in the past I've never had any problems with this app. All benchmarks had 100% success rate. Yesterday I set up nginx to server static content and pass on other requests to apache. Now, if I have 1 concurrent user (-c 1) then everything is fine. But it seems the more concurrent users I have, the more failed requests I get. Not a lot, but maybe about 10 or 15 out of 350. They're "length", whatever that means. Visiting the website with a browser, I don't have any problems at all. How can I find out the cause of these failed requests?

  Read the article

• Options to efficiently synchronize 1 million files with remote servers?

  - by Zilvinas

  At a company I work for we have such a thing called "playlists" which are small files ~100-300 bytes each. There's about a million of them. About 100,000 of them get changed every hour. These playlists need to be uploaded to 10 other remote servers on different continents every hour and it needs to happen quick in under 2 mins ideally. It's very important that files that are deleted on the master are also deleted on all the replicas. We currently use Linux for our infrastructure. I was thinking about trying rsync with the -W option to copy whole files without comparing contents. I haven't tried it yet but maybe people who have more experience with rsync could tell me if it's a viable option? What other options are worth considering?

  Read the article

• Optimize Windows file access over network

  - by Djizeus

  At my company I frequently need to access shared files over a Windows network. These files are located on the other side of the planet, so I guess the file share goes through some kind of VPN over Internet, but I don't control this and it is supposed to be "transparent" for me. However it is extremely slow. Displaying the content of a directory in the file explorer takes about 10s. Even if over the Internet, I did not expect that retrieving a list of file names would be that long. Are there any settings to optimize this from my Windows XP workstation, or is it mostly related to the way the network is configured? The only thing I have found so far is to cache all file names, while by default only short file names are cached (http://support.microsoft.com/kb/843418).

  Read the article

• Nginx as a reverse proxy + Apache or completely cut out Apache? (WordPress Multisite)

  - by user715564

  I am starting a WordPress multisite network with domain mapping and I am trying to think through my server set up. Right now, I only have one medium sized VPS but hopefully I will need to add more servers later so ideally the solution will also accommodate future growth. My question is, would it be better to set up Nginx as a reverse proxy with Apache or use only Nginx? It seems like setting up Nginx as a reverse proxy would be easier and offer less of a possibility of problems but, on the other hand, would using only Nginx add substantial benefits?

  Read the article

• Optimize Apache performance

  - by Phliplip

  I'm looking for ways to optimize our current web server hosted in-house. I'm trying to supply as much relevant information below. Please let me know if you would require additional information in order to assist. Server is running 1 single website, which is an online pizza ordering platform built on Zend Framework (ver1). On traffic stats from the last month aprox 6.000 pageloads per day, concentrated mainly around dinnertime. Around 1500 loads/hour peaks in that period. We recently upgraded from a 2/2mbit aDSL-line to 100/100mbit fiber, and we still have performance issues at dinner time. We assumed the 2mbit was the issue. Website is pretty snappy in low-load periods. Hardware CPU: Intel(R) Xeon(R) CPU 5160 @ 3.00GHz (3000.13-MHz K8-class CPU) Mem: 328M Active, 4427M Inact, 891M Wired, 244M Cache, 623M Buf, 33M Free Swap: 16G Total, 468K Used, 16G Free (6GB physical, 16GB swap) Filesystem Type Size Used Avail Capacity Mounted on /dev/ad7s1a ufs 4.8G 768M 3.7G 17% / devfs devfs 1.0K 1.0K 0B 100% /dev /dev/ad7s1g ufs 176G 5.2G 157G 3% /home /dev/ad7s1e ufs 4.8G 2.8M 4.5G 0% /tmp /dev/ad7s1f ufs 19G 3.5G 14G 19% /usr /dev/ad7s1d ufs 4.8G 550M 3.9G 12% /var Server OS FreeBSD 8.2-RELEASE Software apache-2.2.17 php5-5.3.8 mysql-server-5.5 Apache footprint (example, taken from # top) 31140 www 1 45 0 377M 41588K lockf 2 0:00 0.00% httpd 31122 www 1 44 0 375M 35416K lockf 2 0:00 0.00% httpd 31109 www 1 44 0 375M 38188K lockf 2 0:00 0.00% httpd 31113 www 1 44 0 375M 35188K lockf 2 0:00 0.00% httpd Apache is using the prefork MPM, APC (Alternative PHP Cache). SSL module is loaded, but not utilized (as in don't really work, thus not used). There is a file containing settings for MPM modules, but as i see it's not included in the httpd.conf file, the include line is commented out. Thus i would guess that the prefork MPM is working of default values too. Here are some other Apache conf values that i found - which are included in https.conf Timeout 300 KeepAlive On MaxKeepAliveRequests 100 KeepAliveTimeout 5 UseCanonicalName Off HostnameLookups Off

  Read the article

• compiling the linux kernel

  - by user482819

  Just for learning, I have recompiled the linux kernel with different options, installed and boot from it. It was both instructive and straight forward. However, I was overwhelmed by the big number of options available. My questions are: 1.- Does it make sense to spend time trying to optimize the linux kernel for my particular laptop? Will it make a significant improvement? 2.- Is there any tool that can read the configuration of my computer and suggest a config? Thanks, H

  Read the article

• My system is always disk-bound (the disk light is always on). Why is this?

  - by Scoobie

  I have been given a laptop by the good folks at my company on which to do my work (Java development). I usually use eclipse as my primary development platform. The laptop is a Dell D830 and runs Windows 7 - 32 bit. Although the processor supports a 64 bit instruction-set, licensing limits me to running the 32 bit OS. The HDD is a WD1600BEVT (Western Digital). I have noticed that my disk is always very slow. Windows start up is usually pretty quick, however as soon as I log on, my disk light stays on and usually, the laptop takes about 4 minutes (after logging in -- immediately upon getting the prompt to press Ctrl + Alt + Del to log in) before it's usable. Questions: Is this expected behavior? What can I do to examine the disk and determine the cause of the problem? What can I do to improve my disk's performance? Any optimizations you may be able to suggest? Other Questions: Some have suggested running Process Monitor (from sysinternals), but how would i get the log since start up? Instead of trying to fix this myself, should I simply push this onto the system administrator? Thanks all.

  Read the article

• Speed up MySQL for inserts (for testing purposes)

  - by Alex N

  I have a bit of software that needs to do a lot of INSERTs. In production environment there'll be some serious tweaking and testing and stuff like that, but now when I need to test it I'd like to speed up inserts as much as possible. Hence my question - is there a way to tweak mysql such that it doesn't do much disk I/O but keeps everything in RAM and syncs with disk rarely(like once n-seconds say?)

  Read the article

• Jruby rspec to be run parallely

  - by Priyank

  Hi. Is there something like Spork for Jruby too? We want to parallelize our specs to run faster and pre-load the classes while running the rake task; however we have not been able to do so. Since our project is considerable in size, specs take about 15 minutes to complete and this poses a serious challenge to quick turnaround. Any ideas are more than welcome. Cheers

  Read the article

< Previous Page | 50 51 52 53 54 55 56 57 58 59 60 61  | Next Page >