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275,037 | Why doesn’t a MySQL fulltext search “IN BOOLEAN MODE” fail when referencing a missing column? | First, the background on how I discovered this issue. This happened when using MySQL 5.7 and the DB — as well as the related table — are using MyISAM. I was debugging some code — and related MySQL queries — on a website I manage and found the bottleneck: It turns out a fulltext search was running a [CODE] referencing a... | This is documented behaviour : InnoDB tables require a FULLTEXT index on all columns of the MATCH() expression to perform boolean queries. Boolean queries against a MyISAM search index can work even without a FULLTEXT index, although a search executed in this fashion would be quite slow. Why this exception exists (whic... | 1 | 2 | 951 | 2020-09-06T01:12:49.493 | database_errors | dba.stackexchange.com | |
62,716 | What does it mean if one of the IP-addresses in my resolve.conf times out? | Someone is helping me resolve a response time issue on my VPS. He suggested I look in my [CODE] and make sure neither of the IPs are timing out . My resolve.conf looks like this: [CODE] when I do a nslookup on the second IP, it times out: [CODE] what does this tell me? do I need to inform my vps hosting provider of thi... | if its timing out, perhaps the DNS server is offline? What does this tell you? Well, it means if the primary server fails then your server will not be able to resolv any names aside form the hosts entries. As far as the domain or search followed by the domain name, its just telling your system that if you search for a ... | 0 | 1 | 284 | 2009-09-05T18:12:36.443 | infrastructure | serverfault.com | |
12,484 | What program can I use to benchmark network traffic? | Possible Duplicate: How to test real network throughput between two points? Given two computers connected by some network interface, is there a standard tool used by an academics publishing in peer-reviewed journals to benchmark performance across that interface? | Test run netperf, Nettest or TTCP. not sure of the industry standard status thou. Offtopic: new users aren't allowed to add hyperlinks? | 1 | 0 | 8,799 | 2009-05-27T05:31:40.093 | data_quality | serverfault.com | |
209,331 | Index scan on UNIQUE index for count(*) | I've got a table [CODE] with ~23 million rows (4248 MB in size). There's a column [CODE] in it, with a [CODE] constraint. And a unique index [CODE] on [CODE] . When I do [CODE] to count all the rows in the table, the planner tells me: [CODE] I would have expected a fast [CODE] (index p1 occupies only 698 MB - 6x less).... | As to why you do not get an index scan with [CODE] , you should be getting an index-only scan . Your situation can not yet be recreated with the data you've provided. This certainly works with PostgreSQL 10.4. I can't speak to your own use case, and there are a lot of reasons why you may not get an index scan in the re... | 3 | 3 | 1,184 | 2018-06-11T23:49:04.130 | data_quality | dba.stackexchange.com | |
258,509 | Algorithms: How do I sum O(n) and O(nlog(n)) together? | I have the follow algorithm which finds duplicates and removes them: [CODE] I am trying to find the worst case time complexity of this. I know mergesort is [CODE] , and in my for loop I am iterating over the entire data set so that would count as [CODE] . I am unsure what to do with these numbers though. Should I just ... | [CODE] For Big O complexity, all you care about is the dominant term. [CODE] dominates [CODE] so that's the only term that you care about. | 30 | 78 | 47,606 | 2014-10-08T20:59:28.277 | data_quality | softwareengineering.stackexchange.com | |
361,246 | Setting up user permissions for new user | I want to add a new user to my CentOS 6 server (let's call him Barry). I've made the user account Barry and added him to a group I created called webusers like this: [CODE] Now that I have a user account all set up with a password and added to a group, I want to give the group permission to write to the nginx config fi... | For the nginx conf file, simply make it group writable: [CODE] To allow the webusers group to restart the service, it'll be easiest to do this with [CODE] . If it's not installed, install with (as root): [CODE] Then edit /etc/sudoers with: [CODE] Add some entries like: [CODE] This will allow members of the webusers gro... | 2 | 4 | 7,435 | 2012-02-17T16:14:45.977 | infrastructure | serverfault.com | |
999,931 | Global Administrator / disable having access to the email "open another mailbox..." | I am global admin on a domain and as the name implies, I have access to all emails and having access to their emails via "open another mailbox..." in exchange. Now, one thing I noticed is that I am not able to access one specific user's email account as with any other account. Why is this? How do I check what permissio... | To get the full access rights of these mailboxes, you could ask your Exchange admin(Or using an Exchange admin account) to check whether your account has the access rights of them with the command “ Get-MailboxPermission -Identity -User | where{$_.AccessRights -eq “FullAccess”} | ft Identity, User, AccessRights -AutoSi... | 0 | 0 | 698 | 2020-01-22T13:05:12.260 | infrastructure | serverfault.com | |
318,118 | EMC VNX iSCSI setup - unsure about SP/port assignment | We have a new VNX5300 waiting to get configured, and I need to plan out the network infrastructure before the EMC tech arrives. It has 4x1gbit iSCSI per SP (8 ports in total), and I'd like to get the most out of the performance until we jump over to 10gig iSCSI. From what I can read from the docs - the recommendation i... | What EMC's documents seem to be discussing is to have two separate IP broadcast domains - two separate fabrics on separate hardware, so that a misconfig in a given switch or a switching loop or somesuch doesn't bring down all storage connectivity. Along these lines: I personally think it's a little nuts to keep creatin... | 7 | 4 | 14,896 | 2011-10-03T21:39:11.437 | infrastructure | serverfault.com | |
257,715 | Does ORDER BY COUNT(*) DESC suffer a penalty? | I understand that older versions of MySQL parse the following but has no effect: [CODE] For the following example, does performance suffer and is there a way to overcome it? [CODE] | The optimizer might build a hash table -- key == values of [CODE] , value = count. Or it might extract all the [CODE] values. But in either case, it will have to do some kind of sort at some point. When everything fits in RAM, the cost of the sort is minimal. As a rule of thumb, when the [CODE] and the [CODE] are diffe... | -1 | 1 | 1,072 | 2020-01-19T09:19:29.410 | database_errors | dba.stackexchange.com | |
215,023 | Why C# is not statically typed but F# and Haskell are? | There was a talk given by Brian Hurt about advantages and disadvantages of static typing. Brian said that by static typing he don't mean C# , but F# and Haskell . Is it because of [CODE] keyword added to C#-4.0? But this feature is relatively rarely useful. By the way, there are [CODE] and [CODE] in Haskell which obvio... | I'm addressing the overlap between Haskell and F#'s type systems. The part they share is a simplified subset of a system known sometimes as System F. F# by necessity provides bits and pieces of C#'s type system, but this isn't what the speaker was talking about. Both C# and Haskell/F# are statically typed, but they're ... | 5 | 18 | 4,846 | 2013-10-20T16:59:41.250 | api_errors | softwareengineering.stackexchange.com | |
282,508 | AWS DMS Task getting failed after completion with error as AlwaysOn BACKUP-ed data is not available | I have created DMS task for migrating data from one RDS MS SQL Server instance to another RDS MS SQL Server instance with "Full load + ongoing replication", and data copied to target instance but status showing as failed with below error - Last Error AlwaysOn BACKUP-ed data is not available Task error notification rece... | I don't know if you're still working through this, but I wanted to post the problem & solution for anyone else. There is a bug in the AWS DMS replication engine version 3.4.3 when using RDS SQL Server as a source endpoint, where the 5 minute log backup used for point-in-time recovery with RDS disrupts the CDC process. ... | 3 | 3 | 18,946 | 2021-01-04T02:55:39.213 | database_errors | dba.stackexchange.com | |
360,378 | Server IP doesn't bring me to default "Apache is functioning normally" page | Suddenly the default website shown when going to my server IP isn't the default site (Apache-site) but rather a random domain located on the server. I'm not quite sure what caused it but I no longer get the ''Apache is functioning normally'' message when directly inputting my server IP-adress. I've been reading up on i... | If you have any virtual hosts configured, do not have one for "default" connections, and you request a site that doesn't exist on the server (by IP or any domain name there is no vhost for) you will get the first virtual host configured (order may vary depending on many things). If you post the parts of your configurat... | 0 | 1 | 3,735 | 2012-02-15T14:54:51.793 | infrastructure | serverfault.com | |
373,609 | Partitioning table by aggregate id for efficient eventsourcing in RDBMS | My events are stored in MySQL and I'm reaching a point where I have tens of millions of rows and things are starting to get sluggish when pulling an aggregate I have read about "table partitioning" and was wondering if it was a good option for storing my aggregate events, since an aggregate is just a stream of events, ... | MySql has a limit to the number of partitions you can have on a table, which I believe is currently 8192. Therefore, it may be impractical to have a separate partition for each Aggregate ID, as you would likely run out of partitions very quickly. When altering the table, you'll need to provide a partitioning function t... | 0 | 1 | 130 | 2018-07-05T14:35:12.770 | database_errors | softwareengineering.stackexchange.com | |
245,726 | Is the Java Integer cache a realization of the object pool pattern? | One of the best-known examples of a full-fledged object pool is the JDBC connection pool. Main reasons: objects in the pool are expensive to create and relate with external resources each object in the pool is served to at most one client a time objects in the pool need to be brought back to a clean state before being ... | It is really the flyweight pattern which is a specialized sort of object pool, where objects get shared to save memory. | 3 | 6 | 759 | 2014-06-22T21:32:53.800 | database_errors | softwareengineering.stackexchange.com | |
154,347 | How Can I Connect to remote sql server? | I have a desktop application(Developed in c#) which will use SQL SERVER database. The database is on remote Database Server. I need to connect to that database on this database server and some transaction with this database. I have the internet connection. I know the ip address and port number of sql server in this dat... | IMHO: it is not secure to have sql server listening on public ip address! You should use a vpn or at least a ssh tunnel. Anyway, try to create an alias with ip address, in the MSSQL Client configuration utilty. | 0 | 1 | 639 | 2010-06-24T07:16:55.610 | database_errors | serverfault.com | |
275,441 | MySQL: Why am I getting a syntax error when using the FIELDS ESCAPED BY clause on a select statement | I am attempting to generate a csv file including headers from a table in my MySQL 8.0 database. After a lot of searching I found the following suggest syntax: [CODE] However when I run this statement in mysql I get the following error: ERROR 1064 (42000) at line 1: You have an error in your SQL syntax; check the manual... | This seems to be a simple syntax issue. Use the below query instead which basically doesn't use [CODE] before [CODE] since it's already specified before [CODE] . [CODE] Supporting Resources 13.2.10.1 SELECT ... INTO Statement [CODE] 13.2.7 LOAD DATA Statement | 0 | 1 | 1,333 | 2020-09-12T20:22:06.947 | database_errors | dba.stackexchange.com | |
665,683 | DNS servers trying to send data to Google+ - Google DNS | I was looking through my watchguard traffic today and noticed a lot of traffic going from my two local DNS servers to "Google-Plus". I'm assuming watchguard has that labeled incorrect as the IP addresses they are trying to connect to are the Google DNS addresses (8.8.8.8 and 8.8.4.4). I don't know if this has always be... | why are my DNS servers trying to connect / send data to the google dns servers? Because someone configured them that way. Simple like that. This is not "google +". It is the google public DNS infrascturcture - which is generally assumed to be quite good and fast. My best guess is that it's just trying to update the DNS... | 0 | 3 | 165 | 2015-02-06T21:09:25.897 | infrastructure | serverfault.com | |
198,720 | Unable to start MongoDB with --replSet | I have been trying to install Rocket.chat which requires MongoDB, the instruction for configuring MongoDB is here: https://rocket.chat/docs/installation/manual-installation/ubuntu/index.html#install . I have MongoDB 2.4.10, I appended [CODE] to the end of [CODE] and restarted MongoDB with [CODE] . However, when I run [... | After checking my [CODE] I noticed that it was the configuration for MongoDB 2.6 and newer, that was why [CODE] did nothing. Reinstalling didn't help so I decided to install MongoDB 3.6 from MongoDB's repository, followed the instruction of Rocket.chat and everything worked as expected. | -1 | 1 | 4,159 | 2018-02-24T03:15:46.533 | database_errors | dba.stackexchange.com | |
660,986 | Nginx: request files without extension | How can I request html pages on a nginx server without the extension? Ie: example.com/about should return example.com/about.html. This should be true for all the html pages. I have something along the lines of: [CODE] Which works, but visiting example.com/ causes a 403 Forbidden: [CODE] And visiting a non existing page... | Modify your try_files line to look like the following: [CODE] The reason you are seeing a loop is that try_files will force a redirect to the last entry if no valid location is found during the search. Further reading and reference: http://wiki.nginx.org/HttpCoreModule#try_files | 1 | 5 | 11,449 | 2015-01-20T18:28:36.463 | api_errors | serverfault.com | |
408,430 | How to use the original sender date instead of the fetch date in OTRS | When OTRS fetches emails from an IMAP account it forgets the original send date and replaces this with the fetch (!) date. Normally this is not a problem, but when you're importing an existing IMAP folder with many emails into [CODE] all dates are set to the import data. This is not cool and I would like to know if the... | The solution I found is to add a trigger to MySQL like so: On [CODE] [CODE] On [CODE] [CODE] Same table, but after update [CODE] Finally a trigger on [CODE] : [CODE] | 1 | 1 | 1,587 | 2012-07-17T08:36:10.227 | infrastructure | serverfault.com | |
851,585 | Request Tracker and msmtp error (RETURNED 78) | I have Request Tracker 4.4 up and running. Sometimes email messages that it sends are going to spam. So I decided to use msmtp to send messages through SMTP with authentication. I used this manual: https://rt-wiki.bestpractical.com/wiki/Msmtp Actual result is that mail is not sent, while log says sent and also log says... | Exit status of 78 (EX_CONF) implies a problem with the config file. This could be permissions if the file contains password (or other secrets) or some other problem with the contents of the file. Running msmtp as the RT user (www-data?) should show you what the problem is. For example this is what I see when I have ove... | 0 | 1 | 1,575 | 2017-05-22T15:26:01.297 | api_errors | serverfault.com | |
383,213 | Upstart: stop on runlevel [016] vs stop on starting rc RUNLEVEL=[016] | So, I'm working on an upstart init script for mysql. Should be trivial, right? My stop stanza looks like: [CODE] I [CODE] , and mysql yells about my MyISAM tables being crashed, just like I'd [CODE] 'd my mysql process. Boo. Upstart doesn't seem to be waiting for mysql to quit before restarting. Some searching on Googl... | The issue he is actually caused by Upstarts flexibility in handling both Upstart jobs and SystemV services on Ubuntu. For information on events, a good place to look is the man pages on your system. If you're running Ubuntu Natty or newer, you'll now have upstart-events(7): [CODE] This gives you a lot of information. H... | 6 | 6 | 7,168 | 2012-04-26T01:00:08.407 | database_errors | serverfault.com | |
27,346 | Turning off auto shrink on all SQL Server databases. Why doesn't this work? | I figured I could use sp_MSforeachdb to solve this problem, but I get an error message. [CODE] If I run the above query with the PRINT line uncommented, I get a list of all databases except the system databases. However, when I uncomment the ALTER DATABASE line, I get these two error messages: Msg 5058, Level 16, State... | Unfortunately, the procedure sp_MSforeachdb is and will always be unsupported and thus, kind of unreliable. There's an article on CodeProject that shows how to filter databases when using this DB. But I have the same problem as yours on my local 2008 R2 installation. Filtering doesn't work. Our own friend, Aaron, wrote... | 8 | 7 | 7,509 | 2012-10-22T08:15:12.600 | database_errors | dba.stackexchange.com | |
35,313 | Windows DNS server database scrambled by VPN incoming connections | Simple setup: Primary server (\MASTER): Windows 2008 server standard with following roles DHCP server DNS server AD domain controller Secondary server (\SLAVE): Windows 2003 server standard with following roles DNS server AD domain controller (additional) LAN uses private IPs of range 10.10.1.x. No subnets. Primary ser... | When a remote computer connects to the Routing and Remote Access server by using a dial-up or a VPN connection, the server creates a Point-to-Point Protocol (PPP) adapter to communicate with the remote computer. The server may then register the IP address of this PPP adapter in the DNS or the WINS database. When the Ro... | 0 | 3 | 924 | 2009-07-02T21:27:37.933 | database_errors | serverfault.com | |
1,084,435 | Host key changing during reboot | I have four Azure VM machines running [CODE] that I regularly shut down. Yesterday I shut them down, and early today I restarted them. Usually this presents no problems. Today, one of the machines started giving me the dreaded [CODE] : [CODE] I have not reinstalled the machine - maybe I did a system update yesterday, b... | Run [CODE] . Apparently cloud-init will regenerate keys/fingerprints if the VM's instance ID changes. This file seems to have a long history so it should be easy to tell if it happened around your timeframe. | 3 | 6 | 2,782 | 2021-11-24T03:33:36.660 | infrastructure | serverfault.com | |
300,589 | How to Escape dot(.) In a substitution variable | I have a variable called [CODE] and inside my file [CODE] I have this line: [CODE] Once executed sqlplus complains with the following error when the variable [CODE] contains for example [CODE] : [CODE] I know about the issue with [CODE] (treated as table.column). I tried to use double quotes, but I get an invalid ident... | [CODE] | 0 | 0 | 203 | 2021-10-04T15:20:10.947 | warehouse_errors | dba.stackexchange.com | |
953,557 | how to access external mysql from docker | I have an springboot java app inside docker that needs to access an external mysql. How can I configure this? Is it possible to define it inside Dockerfile? I am now to docker so I assume this should be a simple and common task :) When I run the app I receive the error 2019-02-12 15:10:51,472 DEBUG [main] com.zaxxer.hi... | If the mysql server is running on the docker host, either on metal or in another contianer with a mapped port, it could be that your app's configuration is still looking for the database server on localhost which within its container points to the loopback interface INSIDE the container. You can get around this with th... | 1 | 1 | 6,972 | 2019-02-12T15:16:33.043 | pipeline_ops | serverfault.com | |
14,118 | Linear regression - LMS with gradient descent vs normal equations | I wonder when to use linear regression with stochastic or batch gradient descent to minimize the cost function vs when to use normal equations? The algorithms using gradient descent are iterative, so they might take more time to run, as opposed to the normal equation solution, which is a closed form equation. But it do... | Andrew Ng answers this question succinctly in his Coursera lecture about the normal equation . I will summarize. You have m training examples and n features. Disadvantages of gradient descent: you need to choose the learning rate, so you may need to run the algorithm at least a few times to figure that out. it needs ma... | 4 | 11 | 9,642 | 2016-09-20T21:27:12.427 | data_quality | datascience.stackexchange.com | |
1,109,306 | Postfix: dedicated user to send emails | My current Postfix setup allows to send emails only with the local users (like, if I logged as xyz then email will be sent as xyz@server.com ). I have Courier IMAP server, with the same user xyz but with different password, from the other place. Now I want to setup RoundCube (RC) as a webmail client but, unfortunately,... | Roundcube uses the username and password of the IMAP account for authentication to the SMTP server if you have configured it that way, which is probably the default of Roundcube. [CODE] You can also configure Roundcube to use the login data only for the login to the IMAP account, but to send all emails via a specific S... | 0 | 1 | 349 | 2022-08-28T16:27:08.283 | infrastructure | serverfault.com | |
39,694 | Multiple SQL Server data files on same SAN disk | I'm currently in the process of creating a new database, and have previously only ever used a single data file and a single log file. I've done some research online regarding the benefits of multiple data files, but I've found mixed opinions regarding the benefits of multiple data files on a single disk. So my question... | Even multiple tempdb files on a single LUN should be a last resort compared to one tempdb per LUN. If there are multiple database files on a LUN, and they are allowed to auto-grow, their contents will be interleaved in the filesystem and on the storage. Hit them both heavily with read or write requests, and a situation... | 7 | 6 | 4,016 | 2013-04-10T18:00:40.537 | database_errors | dba.stackexchange.com | |
369,075 | Anyone using RTMP on CloudFront? I can't specify a crossdomain.xml file | I'm using a streaming distribution on [CODE] to serve media via [CODE] . Obviously I want to restrict the [CODE] file but [CODE] is only serving it's default one. The docs give instruction on how to overwrite their [CODE] I have a public, non-restricted [CODE] in the root of my [CODE] (the one with the media files), bu... | The Adobe Flash Media Server crossdomain.xml file specifies which domains can access media files in a particular domain. CloudFront supplies a default file that allows all domains to access the media files in your streaming distribution, and you cannot change this behavior. If you include a more restrictive crossdomain... | 0 | 2 | 872 | 2012-03-13T06:33:47.380 | infrastructure | serverfault.com | |
305,937 | Firewall blocking SQL Server named pipes | If I turn off the firewall on Windows SBS 2011, I can connect to my SQL Server 2008 non-default instance by name (which I presume means it's using named pipes) without incident. After I turn it back on, I can't. I have unblocked incoming TCP and UDP ports 135, 139 and 445. What am I missing? | Here is a link that explains what you could do to resolve this issue http://msdn.microsoft.com/en-us/library/ms175043.aspx | 1 | 2 | 23,379 | 2011-08-29T05:59:55.457 | database_errors | serverfault.com | |
1,011,803 | Conditionally set SSL certificate request header in Apache | I have an Apache 2.4 server configured as a reverse proxy to accept incoming HTTPS requests and reverse-proxy them to another server over HTTP with custom HTTP headers containing any provided client certificate information. A simplified version of my configuration: [CODE] For the most part, this is fine, but things get... | The example of Header expression shows that the entire parameter has to be quoted ("expr=..." instead of expr="..."). I ended up with [CODE] and this worked, the "null" string didn't occur anymore (Apache 2.4.6). | 4 | 2 | 5,050 | 2020-04-10T19:52:06.440 | api_errors | serverfault.com | |
388,477 | Fresh SQL Server DB restore works most times, but fails sometimes | I'm working on an automated setup of a Windows Server 2008 R2 Core with IIS and SQL Express I'm starting with a fresh (just installed) OS in a VM (virtualBox in this test case) My scripts then create users, install dot.NET 3.51 and 4, IIS and SQL-Server 2008 R2 Express. They also set up web sites and services, all is f... | I haven't figured out why this happens, but I now have a workaround in place. I just run my restore script twice. The second time it always works!!! I added some T-SQL code to the restore statements to only restore it if it failed before or has not been restored at all. This way, only the databases where restoring fail... | 0 | 2 | 975 | 2012-05-12T12:00:41.573 | database_errors | serverfault.com | |
255,651 | Exploits on Server | Possible Duplicate: Tips for Securing a LAMP Server. First of all sorry for my stupidness. I run a server, but everytime (once a week) it get 'hacked' by some things. The index is changing to "Hacked By XXXX". I could grep an ps aux | grep php and found a line like this: apache 43434 xxx php iphone.jpg - Normally it is... | If these hacks are repeating, maybe you've not corrected the exploited vulnerability. If you're using CMS, update them with the latest version. If you're running your own code, analyse it, get some help to debug it and find the hole. For now your hacks were quite limited. An index change is not a big deal. But maybe on... | 0 | 0 | 148 | 2011-04-04T21:06:59.147 | data_quality | serverfault.com | |
935,762 | Service account with only objectViewer | I have a Google Cloud Registry for docker images and want to create a service account that can´t push images to the registry, just pull. When I creates a service account it inherits my permissions and I can´t remove the unwanted permissions. What am I missing? | You can create a new service account through IAM . During the process of account creation, you can choose the IAM roles you want to assign it. In the case where you have already created the service account and it has inherited permissions you don't want it to use, you can go to IAM and change the roles assigned to the ... | 0 | 0 | 397 | 2018-10-16T14:47:28.277 | pipeline_ops | serverfault.com | |
1,030,236 | When does iptable's conntrack module track states of packets? | It first needs to store states. With some old BSD firewall that I used, I guess was named IPFW, I used to put a rule that sated "keep track of the state of the leaving packet", and this was placed on the outbound direction of interfaces. Then, another rule on the inbound direction that checked them against those states... | Introductory presentation of Netfilter and conntrack First the mandatory schematic about Packet flow in Netfilter and General Networking: Netfilter is the packet filtering framework inserting itself over the rest of the network stack (represented by "routing decision" and other white round-edged box parts). Netfilter p... | 5 | 11 | 16,885 | 2020-08-15T12:13:40.910 | infrastructure | serverfault.com | |
28,398 | specific feature engineering for specific algorithm | Days ago,One AI financial service provider offered us a lesson and mentioned that you are supposed to perform specific feature engineering according to the specific algorithm you are using.For example,when using logistics regression,fitting more features（uncorrelated）like binning the continuous variable into discrete o... | In general, features are engineered so as to retain optimum relevant information present in the dataset with succinct representation and then features are adapted so that an algorithm can accept it as input. Feature engineering generally involves methods like binning, PCA, etc. Adapting those features to pass to algori... | 0 | 1 | 257 | 2018-02-28T10:34:21.550 | data_quality | datascience.stackexchange.com | |
49,964 | Will column be overwritten when add column is executed? | [CODE] What if column abcd_nid already exists ? Will it be overwritten ? how can I insert new values into column ? | You did not mention which database you are using, however trying to add a column that already exists will produce an error. All the databases that I have worked with require a column name to be unique within a table. (No room for two abcd_nid columns.) To update the column you use the standard UPDATE command. | -3 | 2 | 54 | 2013-09-16T12:55:57.740 | warehouse_errors | dba.stackexchange.com | |
162,120 | How make my architecture scalable to handle linear process | I have a system to calculate Real Time Traffic (RTT), using Automatic Vehicle Location ( AVL ). I can know where the car was, where is now, and calculating distance and time can estimate the traffic speed on those roads. I have two store procedures: [CODE] using avl [CODE] found the near road link [CODE] using pgroutin... | Since you suspect the disk is the limiting factor, upgrading to SSD sounds like your best option if you are focused on hardware. More RAM might also work, if it would allow to cache most of the slow table/indices. (How big is map_rto and its most-used index)? If you would rather try tuning the hardware you already have... | 0 | 0 | 60 | 2017-01-24T19:58:34.803 | warehouse_errors | dba.stackexchange.com | |
16,164 | Any up to date tutorial on how to setup Postfix + Dovecot with virtual users on Debian? | Any up to date tutorial (for dummys) on how to setup Postfix + Dovecot with virtual users on Debian? | You asked for "up to date", so something from 2007 shouldn't be too far off: http://workaround.org/articles/ispmail-etch/ If that's too old, then it doesn't look like there's 1 specific tutorial covering what you're looking for (maybe you could write one when you get done?) but a combination should work: No date given,... | 0 | 4 | 625 | 2009-05-31T12:00:22.817 | infrastructure | serverfault.com | |
329,391 | Portscan attacks from somewhere | I realize this is a lamer/beginner question, but I've been attacked by a couple of addresses in China and I'm not sure how to close the hole. My snort logs (yes I'm using snort! I see you are impressed) show things like this: TCP Portscan [CODE] And [CODE] : [CODE] I don't understand what this means, but I think it mea... | To my eye those alerts are simple background noise. Just by being internet visible you'll get 'portscan' alerts in any firewall or IDS system. Are they an attack? No, not really. They're just jiggling door handles to figure out which doors are possibly open. This is a recon step before anything else is done. Snort thro... | -4 | 6 | 815 | 2011-11-09T17:36:46.540 | database_errors | serverfault.com | |
660,649 | Puppet master (3.6.2) error on signing puppet client (2.7.25) | I was hoping someone might have an answer for this: While upgrading overall from Centos6 to Centos7 I'm handling the upgrade for puppet's version. Our new puppet server's version is [CODE] and I'd like it to work with the somewhat older puppet clients whose version is [CODE] . This is the problem I'm running into: pupp... | I had the same problem. You have to update your puppet clients: https://tickets.puppetlabs.com/browse/PUP-3176 | 2 | 0 | 2,186 | 2015-01-19T15:16:10.903 | pipeline_ops | serverfault.com | |
316,580 | Adjusting Index for Better Performance | I've just started my journey as a dba and I figured out using a script that my database indexes are a mess. Here they are: And here is what the script tells me about them: Can you give me insights about how to fix them and what I should consider (logically speaking) when doing it? I have no idea where to start. | Agreed with everyone's comments so far, most importantly with index tuning is understanding your queries use cases so you know what indexes are being used, what indexes are missing and could be helpful, and what indexes are wasteful. It looks like you're using scripts from the First Responder Kit , such as [CODE] which... | 2 | 2 | 75 | 2022-09-07T19:10:14.307 | warehouse_errors | dba.stackexchange.com | |
875,229 | Two Way SSL Error - 400 The SSL certificate error just for client certificate | I am trying to configure two-way SSL with SSL certs (for server and client) signed by Intermediate CAs. This is what I have done so far following this tutorial . Server - nginx application Nginx is configured with SSL certificate (signed by an Intermediate CA). [CODE] Client - curl or OpenSSL s_client I have a client c... | Finally, I have pinned down the root cause of the problem. There were two problems with my setup. a) For two-way SSL, the certificate signed by the Intermediate CA must have [CODE] in [CODE] (Thanks to @dave_thompson_085) which can be verified by the below command [CODE] b) Another, thing which was missing was ssl_veri... | 21 | 29 | 71,208 | 2017-09-24T11:39:45.297 | api_errors | serverfault.com | |
830,658 | Root Authentication failed after update in CentOS 7 | I'm newbie to Server staff, I try use this command via ssh to update CentOs 7: yum update Or yum upgrade But after update i reboot VPS and try to login in via root account then authentication failed. It's seems root password changed after update. | How are you logging in to root ? at the login prompt ? or using su ? While not super familiar with centos. the update may of disabled ssh root login but you may be able to run something like sudo bash with your root password, from your normal account. Cheers Roygul | 0 | 0 | 1,169 | 2017-02-05T04:09:54.563 | api_errors | serverfault.com | |
751,458 | How to set the minimum acl permissions for an user who is included in two or more user groups with different permissions in linux? | Say, I have two groups G1 and G2 with user1 as member to both. G1 has rwx permission on a file file1 and G2 has only read permission on the same file. Setting G2 as the primary group for user1 does not prevent it from having rwx permissions on file1. I wish to use acl to allow user1 to the have only G2's permissions(Th... | Is it possible for any user which is part of multiple groups to have the same permissions as the most restricted group it belongs to? No, it is not possible. Since user1 can get larger permission via group G1, these are the final permissions that apply. Any different behavior would break the permission system. For inst... | 0 | 0 | 128 | 2016-01-25T05:02:38.593 | infrastructure | serverfault.com | |
29,541 | Karma/ Jasmine testing framework - tests don't appear to be executed | I am looking to implement the Karma/ Jasmine test suite/ framework for use with my AngularJS app. Having never used a testing framework previously, I have followed the tutorial - to give it a go, before trying to integrate it into my existing AngularJS app. But, when I run [CODE] in the command line, although a browser... | Your issue seems to be that the tests are not running. To resolve it, you can follow these steps: Make sure the Karma configuration file, karma.conf.js, is correctly configured. The file should specify the path to your tests and source files, as well as the browsers you want to run your tests in. Check the syntax in bo... | 5 | 0 | 1,358 | 2017-09-14T11:20:40.777 | data_quality | sqa.stackexchange.com | |
984,497 | postfix 3.3.0 has fatal error "bad string length 0 < 1" | I'm migrating my mail server from an older instance of postfix (3.2.0) to 3.3.0 on Ubuntu. I'm installing from apt and installation went fine. I'm in the process of trying to set up my MySQL connections , copying them from my old system to this one. I'm running into a problem when I try to run [CODE] . The error I get ... | It looks like the [CODE] argument for [CODE] wants a path. When I run the command [CODE] , it works. Not sure where the path is relative to. I tried putting the config files in [CODE] and that didn't work. The mail log is still showing that there was a lookup error. I could still use help there. | 1 | 1 | 4,843 | 2019-09-17T01:11:19.403 | database_errors | serverfault.com | |
58,086 | Design Code Outside of an IDE? | Does anyone design code outside of an IDE? I think that code design is great and all but the only place I find myself actually design code (besides in my head) is in the IDE itself. I generally think about it a little before hand but when I go to type it out, it is always in the IDE; no UML or anything like that. Now I... | When it comes to discussing a problem or designing, nothing beats the Whiteboard . You should use a whiteboard and informal UML sketches to discuss things. After that you should go to the IDE. It is slightly tedious to have formal and complete UML sketches for the design because, then you will have to maintain them as ... | 6 | 10 | 971 | 2011-03-14T15:45:37.510 | data_quality | softwareengineering.stackexchange.com | |
368,761 | DKIM on postfix relay server | I have a postfix/amavis relay server, with the domain name mail.example.com. It will be a relay for dozens of VPS's, which will have domains like hostname.example.net. So i have actually two questions. Is it possible to use dkim to sign the mails originating from the VPS's over the postfix relay on the relay server? Or... | I have resolved this question with OpenDKIM by using SigningTable , KeyTable and TrustedHost parameters. /etc/opendkim/KeyTable – a list of keys available for signing /etc/opendkim/SigningTable - a list of domains and accounts allowed to sign /etc/opendkim/TrustedHosts – a list of servers to trust when signing or verif... | 7 | 4 | 11,788 | 2012-03-12T10:36:30.653 | infrastructure | serverfault.com | |
270,065 | Optimal mySQL design for 500k+ products with up to 50 specs | I facing a problem where I have to design a MySQL database capable of containing +500k products in approx. 1.500 categories, that can hold up to 50 specs. (like size, weight, speed, color, etc). My goal is to find/use a design that is optimal (fast) for selecting products base on the input of up to 50 specs. Later on, ... | A common request. You are actually a step ahead of most questions tagged with [CODE] -- you have thought about "common use patterns" and how to optimize once you gather that info. You should be able to make an initial guess at what is most common, put them in columns for efficient searching, put flag-like attributes in... | 1 | 1 | 113 | 2020-06-29T09:58:51.890 | database_errors | dba.stackexchange.com | |
1,128,041 | Forcefully forget / unmount ZFS pool after drives disconnected | First off, I made a mistake & I acknowledge that, but now I'm stuck with a "broken" ZFS driver and want to restore it without rebooting my machine. How I can say ZFS on Linux to just forget the existence of a pool (forcefully unmount & "export" it) while all drives are disconnected? While I had a running ZFS pool with ... | While writing this exhaustive error description, I got it back up running by re-connecting the drives in the correct order because Linux new decided to use their old names again (so ZFS can find them at the same path), ran [CODE] and they were up again. If you connect them in the wrong order (e.g. old sdc shows now up ... | 2 | 0 | 672 | 2023-04-06T10:13:42.410 | database_errors | serverfault.com | |
755,504 | PHP-FPM crashes when having too many users while doing a heavy job | I have a Server running Apache/2.2.22 (Debian), PHP 5.6.17 as FPM and MySQL 5.6.25. The project runs using a CMS called Redaxo (I don't think it's that important, but I'll tell ya anyway). In Redaxo there are some functions which take some time (e.g. deleting cache and rebuilding it takes 1-2 minutes). In this time, wh... | I've seen similiar errors before. Probably it's related to PHP cache modules. Try the following: ;php-fpm.conf: pm.max_spare_servers = 30 pm.max_requests = 200 pm.start_servers = 30 ;enable slowlog - it gives you readable stacktrace slowlog = /var/log/php-fpm-slow.log request_slowlog_timeout = 10s listen.backlog = -1 T... | 1 | 1 | 1,055 | 2016-02-11T10:16:22.020 | database_errors | serverfault.com | |
738,757 | Is it possible to configure ARR to make TLS 1.2 outgoing connections in Server 2008 R2? | In summary, we need to use Application Request Routing 3.0 to securely reverse-proxy HTTPS requests made to a web server, to the same URL on an application server, where both servers are running Windows Server 2008 R2. The web server is allowed to support incoming and outgoing TLS 1.0 and TLS 1.2 connections, but the a... | This will change the OS defaults in a way to allow all TLS versions (or even SSL if you choose). I tested this on ARR Windows 2008 R2. Windows Easy Fix Patch | 3 | 3 | 5,752 | 2015-11-24T22:59:03.863 | infrastructure | serverfault.com | |
60,950 | Windows XEN VM - Any performance benefit with multiple partitions in the VM? | I'm moving a physical windows machine that has 2 disks and partitions setup for each to a Xen environment. Is there any performance benefit in setting up both partitions (C Drive and D Drive) for this VM in Xen? Or will Windows behave the same using 1 virtual disk compared to 2 virtual disks? Thanks! | If the two partition files are on the same storage volume in the virtual server, no performance will be gained, but if you have software installed on the system already you won't have to reconfigure things by keeping it as it is. If you move the virtual files to different storage volumes on the virtual server then you ... | 0 | 0 | 456 | 2009-08-31T22:08:57.280 | infrastructure | serverfault.com | |
90,408 | How can I set up Redmine => Active Directory authentication? | First, I'm not an AD admin on site, but my manager has asked me to try to get my personal Redmine installation to integrate with ActiveDirectory in order to test-drive it for a larger-scale rollout. Our AD server is at host:port [CODE] and I have a user [CODE] . Right now, I also have a user [CODE] in Redmine using loc... | Okay, so here are the specific settings that I needed in order to make this work: [CODE] The trick was removing [CODE] from the Base DN, after which it all sort of came together. The other notable thing was the inclusion of a user to read the directory. Lastly, the user that logs in uses their user name without domain ... | 10 | 15 | 36,735 | 2009-12-02T23:04:44.917 | api_errors | serverfault.com | |
371,827 | Pessimistic concurrency in a web application | I am working on an application that will support working in multiple tabs at the same time. Currently, when a document is locked by a user, other users won't be able to acces the same document but the same user could, if he wanted, open that same document again in a new tab. My problem at the moment is, when the user c... | Does the user really need to open the same document in 2 tabs at once? If that's really a real use case, just make the second copy read-only. Only let one tab open for editing across all users. You could make the lock trigger after the first edit (first keypress, e.g.). Then if they hit refresh, they lose their changes... | 0 | 1 | 523 | 2018-05-30T18:11:19.633 | api_errors | softwareengineering.stackexchange.com | |
495,573 | Can I use Google's public DNS numeric ID for my nameservers? | Recently I have got a nameservers update problem. But two weeks have passed and the new nameservers are still not updated at most of my local ISPs. It seems those updates are manual. There must be a better way!!! Indeed, Google public DNS servers updated almost immediatelly. But can I go to my server, open the cpanel a... | No, that won't work. When you tell the internet, please use [CODE] as my nameservers, everyone will ask that IP where it should go to find [CODE] . The problem is, [CODE] doesn't actually know , it will (normally) ask your real nameservers, then cache that result and return it to anyone that asks. If you set your names... | -3 | 6 | 111 | 2013-04-02T23:01:05.717 | infrastructure | serverfault.com | |
933,944 | Kubernetes in production. Problems with a working pod | I have a question with kubernetes when deploying a new version. My yaml configuration of Kubernetes has the [CODE] . The problem comes when it comes to changing versions this way. If I have a php-fpm that is performing an action, does that action get lost? In case it is just changing that pod to the new version. My mai... | To expand on what @Fady said above, for those that still may be curious. By calling the PreStop container hook you can close all loose ends before the container is terminated. From the documentation "PreStop: This hook is called immediately before a container is terminated." [1] The PreStop hook can execute a specific ... | 0 | 0 | 93 | 2018-10-04T10:53:17.777 | pipeline_ops | serverfault.com | |
1,116,333 | SPF Error - Cannot send emails to @gmail users | I get the following error, every time I tried to send an email to a gmail user. [CODE] Can someone help me? Thank you in advance. | Your SPF policy denotes who are allowed to send email on behalf of your domain. It currently looks like : [CODE] The server that was attempting to send e-mail, with IP-address 83.235.69.32, is not included in that list in any way. Therefor gmail refused to accept the message. Exactly how your SPF record is configured. ... | 1 | 0 | 2,705 | 2022-11-22T15:09:41.867 | infrastructure | serverfault.com | |
323,264 | Sysbench errors out on mysql OLTP test | I am running sysbench on a RHEL 5.6 server running MySQL 5.5.16 using the following setup: [CODE] This creates the default sbench table like so: [CODE] Running a 16 thread innodb read/write test on 1,000,000 rows: [CODE] results in the following error [CODE] I'm fairly new to using sysbench, but is this a bug, or did I... | Nevermind, I think I found it. I was setting up the test with --oltp-table-size=1000000 (1m), then running a test with --oltp-table-size=100000 (100k) Ran it with the right number (1m) and 16 threads finished successfully. | 1 | 1 | 3,006 | 2011-10-20T13:11:54.640 | data_quality | serverfault.com | |
86,228 | Model to detect specific semantic content without labeled data | I want to build a model that can detect sentences that discuss requests for communication - like 'email me', 'phone us', 'contact us', etc. However, I do not have any labeled data which I can use to simply train a neural network. How can I go about solving this problem? On way I was thinking was to create an initial la... | First, this is not sentiment analysis , which is about quantifying "affective states", i.e. something along the lines of "like / don't like". This would rather correspond to a specific application of general text classification: predicting whether a sentence contains a contact request. Now about the specific problem: y... | 1 | 0 | 25 | 2020-12-03T08:52:56.067 | data_quality | datascience.stackexchange.com | |
584,183 | DHCP For Voice And Data VLANs With Router-on-a-Stick | Background: I have 2 Powerconnect 62xx switches stacked with a Watchguard XTM-26 between them and the outside world. Currently all devices connected to the switch are in the same vlan and the default gateway is the watchguard. We've recently installed Polycomp SoundPoint 335 Voip handsets. Because of port limitations, ... | You have a layer-3 switch... This can be accomplished by enabling routing on the switch. Create a VLAN interface and IP address on the voice VLAN. Your default gw for anything that needs to communicate across VLANs should be that interface ip. Same for the data network. Your default gateway should be the switch. Add he... | 0 | 1 | 2,920 | 2014-03-24T15:33:54.323 | infrastructure | serverfault.com | |
370,451 | Is it ok to have validation layer before access control layer | I am creating an API strcutured web application and in this application we have different layers which are doing their own job. First layer is Validation layer which validate user input and if it passes the validation we move that to second layer (which is Access Control layer ) otherwise return the error message Secon... | It depends on whether knowing the validity of some input for a task that you aren't permitted to do is a security leak. If it is, you really should to do it the other way round. The only safe response to an unauthorised user is "access denied". If sometimes the response is "bad request" and other times "access denied",... | 27 | 59 | 6,815 | 2018-05-04T11:13:49.103 | data_quality | softwareengineering.stackexchange.com | |
102,292 | Trace Flag 4199 - Enable globally? | This may fall under the category of opinion, but I'm curious if people are using trace flag 4199 as a startup parameter for SQL Server. For those that have used it, under what circumstances did you experience query regression? It certainly seems like a potential performance benefit across the board, I'm considering ena... | Personally, whenever I build a new server for a new project I always enable TF4199 globally. The same applies when I upgrade existing instances to newer versions. The TF enables new fixes that would affect the behaviour of the application, but for new projects the risk of regression is not an issue. For instances upgra... | 20 | 22 | 17,841 | 2015-05-22T15:56:43.857 | database_errors | dba.stackexchange.com | |
227,126 | mysql trigger data from a many to many relation | I am new to triggers, so I want to know how I could select attributes from 3 different tables to insert them into a new table. I have 3 tables with a many to many relationship: table [CODE] wich has [CODE] and [CODE] table [CODE] which has [CODE] and [CODE] table [CODE] which has both of the id's [CODE] and [CODE] , th... | Don't use a [CODE] , use a Stored Procedure. Normally a Trigger acts on a single table, in response to an [CODE] / [CODE] / [CODE] on that one table. To build a many:many relation, you need "names" from two different tables. That can't happen with a single insert/etc. The Stored Procedure would take the two names you m... | -1 | 2 | 1,083 | 2019-01-14T21:29:06.030 | database_errors | dba.stackexchange.com | |
636,327 | SSH Login Failure "-bash: error while loading shared libraries: requires glibc 2.5 or later dynamic linker" | I did a blunder on one of my production server and its very old RHEL 4 host. Due to recent "shellshock vulnerability" by mistake I upgraded the bash to wrong version from RHEL5 repo. Now I am getting the error [CODE] . Complete Error : [CODE] Now I am unable to login to server also I tried rebooting host with older ver... | You can do the following Reboot the host with console option and Edit grub to add [CODE] at the end of the kernel line and boot so that you will get the shell Now Mount the proc partition [CODE] Remount the root partition : [CODE] Do remove the new rpm [CODE] Confirm you have old version [CODE] Now reboot | 2 | 1 | 2,072 | 2014-10-11T22:04:47.980 | infrastructure | serverfault.com | |
226,161 | normal hexadecimal to 0x hexadecimal conversion in oracle | i am using rawtohex to convert clob data to hexadecimal value as below: [CODE] getting the proper result as well, but the result i am getting as: [CODE] but i want the result as: [CODE] starting with 0x and the same will be not handle for null value, means for null it should come as null only not the 0x please suggest ... | How about concatenating '0x' to the return value of RAWTOHEX()? Eg [CODE] For processing the NULL values, you could use CASE. [CODE] | -1 | 0 | 583 | 2019-01-02T14:00:44.857 | data_quality | dba.stackexchange.com | |
958,960 | LetsEncrypt certificate for parked domains | Hopefully you can shed some light on what might be going on here: I have migrated website [CODE] from external VPS on my private server. I also have several domains, which are meant to redirect traffic to [CODE] ( [CODE] ) In fact, I have migrated like 10 websites ( totally like 100 domains ), thats why Im using ports ... | Roughly speaking, if you want to request a Let's Encrypt certificate for a hostname / domainname that does not point to the system that you run certbot on, then you can't authenticate and validate that you are authorized to and control the domain name by responding to a web request made to that host-/domain-name. You w... | 1 | 3 | 453 | 2019-03-19T13:25:54.643 | infrastructure | serverfault.com | |
546,373 | Custom http Logs Haproxy | Hi I am trying to configure Custom logging for my Haproxy version 1.4.22. I am using option httplog and option asap when I add [CODE] in listen section I get below error [CODE] Errors found in configuration file, check it with 'haproxy check'. I would like to know where should I put directive log format in my haproxy c... | The directive should be [CODE] , not [CODE] . However, custom log formats aren't available in 1.4.x; you'd need to upgrade to 1.5 in order to use that. | 2 | 2 | 1,972 | 2013-10-16T11:32:44.430 | infrastructure | serverfault.com | |
36,524 | UNION is slow but both queries are fast in separate | Dunno what else to do about this one. I have one table that has has a start and a stop columns and I want to return the results of it joined both by start and by stop and I want a clear distinction between the two. Now both queries run fast separatly: [CODE] So this one takes 0.063. But if I combine it in a UNION (does... | I would expect this to happen because of the ORDER BY you have in there. Try this in the first part of the UNION: [CODE] And this in the second part: [CODE] And then replace the [CODE] with [CODE] In other words, remove the need for the IF in the order by. | 15 | 1 | 36,290 | 2013-03-12T19:47:43.193 | warehouse_errors | dba.stackexchange.com | |
258,902 | Warning in Apache log: Cannot get media type from 'x-mapp-php5' | I have no idea what is causing this issue, but it seems to be related to the displayed file (just a simple index.php to print phpinfo) being in an aliased directory. Any suggestions what I can do to avoid the warning? Here's an excerpt from my httpd.conf: [CODE] The last three lines were required to make php work at al... | Try to find and remove/comment [CODE] from your apache configs and .htaccess file. | 8 | 2 | 10,244 | 2011-04-12T18:21:58.273 | infrastructure | serverfault.com | |
27,955 | Partitions and Indexes, in which cases should be used | I know some knowledges: Partitions used to achieve better performance (like described in this article) And indexes used to increase performance in selection operations. And as result my question: in which cases i should use indexes and in which cases i should use partitioned tables. In other words what should be better... | Easy: you should always use indexes. Partitioning for performance is probably the most misunderstood myth out there. When you partition, the best you can hope for is on-par performance with a non-partitioned table. And yes, that is including partition elimination enhancements. Reducing table scans to partition scans be... | 2 | 8 | 134 | 2012-10-31T12:53:37.197 | warehouse_errors | dba.stackexchange.com | |
312,124 | How to monitor the workers used over a period of time? | Assume I have the default setting of max workers or say I have x number of max worker threads configured. Is there any windows or sql performance counter to monitor the number of workers used over a period of time? | You can run this query at a frequent interval of your choice and save the result in a table. [CODE] Remember: The actual number of query requests can exceed the value set in max worker threads in which case SQL Server pools the worker threads so that the next available worker thread can handle the request. A worker thr... | -3 | 2 | 613 | 2022-05-14T12:23:25.683 | warehouse_errors | dba.stackexchange.com | |
938,959 | How to eliminate chunked response delay from NginX? | We have a cascade of two NginX reverse proxies in front of a Java web server. The first proxy runs on FreeBSD (11.1-RELEASE-p10) load balancers and proxies all internet traffic into the internal network. There are two such load balancers. They have an identical config: [CODE] The second proxy runs on CentOS application... | If you're on nginx >= 1.8 you can use: [CODE] | 3 | 1 | 2,360 | 2018-11-07T11:04:44.457 | pipeline_ops | serverfault.com | |
53,377 | How to interpret a random variable in the variable importance? | I have a problem, for simplicity let's say it is a binary classification problem. I am trying to solve this problem using XGBoost. A standard output plot for any ML algorithm, is the feature importance, and I want to look at the top n features. But how to decide on n ? A method would be to add a random variable (a vect... | I'll go through your questions one by one: ... how to decide on n ? This is a completely arbitrary choice that depends on your subjective preferences, the nature of your data, your problem at hand, the amount of computational power you can afford, you name it... There is no rule-of-thumb on this. What is the purpose of... | 0 | 1 | 226 | 2019-06-07T09:45:55.030 | data_quality | datascience.stackexchange.com | |
351,890 | High Availabiltiy Mechanisms For VMWare View Connection Server | According to the question Reboot VMware View Connection Server a reboot of the VCS disconnects all virtual desktops. Are there any builtin mechanisms to provide high availability? | You install secondary servers in replica mode to provide high-availability. See this blog for a detailed explanation. | 1 | 1 | 715 | 2012-01-20T13:33:11.267 | infrastructure | serverfault.com | |
692,804 | How does acting as an RDP host affect UDP visibility/routing? | This is an odd one. First, THIS IS NOT A NETWORKING ISSUE. This is an "rdp host behavior" that can be seen, from one persective, via the behavior of an RDP app. (see What happens to a Windows 7 workstation that acts as an RDP host? for the bigger story) Why is it when I rdp from one machine to another (both of them Win... | In general, nothing should happen to UDP traffic when you connect to a host using RDP. Have you tried running a network capture tool such as wireshark? | 0 | 0 | 138 | 2015-05-18T16:48:15.700 | infrastructure | serverfault.com | |
999,596 | Is it okay to use same SSH keypair for different servers, and how not to? | Initially i tried (and failed) to generate a new SSH keypair for a new server. By default it offers to save it into [CODE] , which obviously i couldn't, so as to not overwrite my existing key. So instead i saved it under [CODE] . But when i copied the newly generated public key onto the server, it didn't work "out of t... | 1. Using the same key for more than one server is not a security issue. As long as the private key is safe, you don't need to worry. 2. SSH does not automatically detect keys, apart from the default one. So if you want to use different keys for different hosts, you have to either specify the key with the [CODE] switch,... | 1 | 2 | 4,084 | 2020-01-20T03:45:22.867 | infrastructure | serverfault.com | |
198,343 | Import bacpac from SQL Azure into local server fails. | We are trying to import a bacpac into a local SQL 2017 instance but it gives the following error. This suddenly started happening, previously we didn't have any problem with it so I can't think of any change that could have caused this. Copying the SQL database via the portal into another SQL Azure server still works t... | I know this is not a permanent solution but by removing the FK constraints it could export and import the database. It was all focused around 1 rather large table. I have no idea what's the possible underlying issue here. Now I have to copy the production database to another server on Azure, remove the constraints ther... | 0 | 0 | 588 | 2018-02-20T08:13:03.010 | database_errors | dba.stackexchange.com | |
40,065 | Can putting mysql DB into memory or having the innodb_buffer_pool_size match the size of DB increase performance? | We have a mysql database that has roughly 80 gigabytes (GB) of data using inno_db engine. We are looking to increase performance on the database (we looked at the slow log and gone through and optimized the db and indexes) and one avenue is to get better hardware. Currently our mysql DB is on a 6 year old server with 1... | I have a client at my employer's company with 192GB RAM using 162GB Buffer Pool. Here is what we did for the client InnoDB Tuning : I set the following options innodb_read_io_threads (maxed it to 64) innodb_write_io_threads (maxed it to 64) innodb_thread_concurrency = 0 (It's default now in MySQL 5.5/5.6) innodb_io_cap... | 1 | 4 | 2,065 | 2013-04-15T21:07:17.027 | database_errors | dba.stackexchange.com | |
779,566 | rsyslog ignoring settings file | changing the [CODE] has no effect for my rsyslog. After changing the settings I call [CODE] and it starts up without any problems. I for instance tried commenting out all rules but it keeps logging as before. And every log message is logged to the mysql but the rule says it should only log the message from the remote h... | For some reason restarting rsyslog seems not reload all the settings, a reboot of the system solved the problem. | 1 | 1 | 1,147 | 2016-05-28T11:23:20.217 | database_errors | serverfault.com | |
1,019,518 | “a specified logon session does not exist. it may already have been terminated” after i joined the device to azure active directory | "a specified logon session does not exist. it may already have been terminated" after i joined the device to azure active directory -i can't access our shared folder in our server after i joined the device to azure AD and use office 365 account (Please see click the link below to see the error image for your reference)... | Azure AD joined devices and Office 365 user accounts don't have access or permissions to your on premises file server resources. You'll need to use a local account to access the file server. | 0 | 0 | 1,257 | 2020-06-01T09:49:12.287 | infrastructure | serverfault.com | |
427,037 | Virtual Windows Servers and Pagefile location | Considering that Windows makes heavy use of the pagefile even with huge amounts of RAM available, is it not best to have this pagefile on the fastest disk possible as close to the virtual systems as possible? I'm thinking, RAM disk. Where I work, storage for VMs is out on a NAS/SAN. I'm worried that so much memory acce... | You can place your VM's swap area (the one the hypervisor uses to swap out vRAM to) to a faster LUN/datastore that doesn't use thin provision and is backed by the fastest spindles/NAND your array has and leave the pagefile within the OS's supervision and on it's OS installation partition. Monitor the swap area usage an... | -5 | 3 | 4,860 | 2012-09-13T10:35:21.237 | infrastructure | serverfault.com | |
307,687 | catch and understand transaction rollback | Because of the data consistency issue of the application (sporadic data loss) I have to perform a deep dive into transaction handling. I've created an extended event session: [CODE] Now I get a lot of DUI statements shown in this ext-event session, all of them are in autocommit mode but there is no one error message. N... | Do you have an idea, why an autocommit transaction has a transaction_state "Rollback" with no errors? The client can abort a running batch by sending an " attention ". This is how you cancel a running query in SSMS, and this is how timeouts work. You can add the [CODE] event to your trace, eg [CODE] | 5 | 6 | 372 | 2022-02-18T13:23:34.937 | database_errors | dba.stackexchange.com | |
300,474 | Iptables not allowing ICMP requests from remote machines | I've configured my linux router with the following iptables rules [CODE] eth1 and eth2 are wan interfaces. vmbr0 is my private network. Ping requests to eth2 ip address from a remote machine are being dropped and so are http requests. How can I fix this? | It appears that every rule you have listed is an ACCEPT rule, including the defaults. From that, your configuration should not drop or deny any packet. I think your issue is elsewhere. | 2 | 0 | 6,892 | 2011-08-12T12:44:06.210 | infrastructure | serverfault.com | |
243,468 | Windows command "net use" failed when login with a no password account | My experimental network: 2 windows 7 PCs. When using below commands trying to connect to PC2 (admin account with no password): [CODE] It will get: [CODE] However, if set a password to PC2 admin account, and do below: [CODE] This will work. Is it necessary to have the password set to enable windows file sharing? | By default, blank passwords aren't allowed for network login. To change this, modify the relevant setting in the Local Security Policy MMC snapin. [CODE] See here for details. | 2 | 5 | 27,722 | 2011-03-04T23:46:46.470 | infrastructure | serverfault.com | |
166,968 | ZFS with L2ARC (SSD) slower for random seeks than without L2ARC | I am currently testing ZFS (Opensolaris 2009.06) in an older fileserver to evaluate its use for our needs. Our current setup is as follows: Dual core (2,4 GHz) with 4 GB RAM 3x SATA controller with 11 HDDs (250 GB) and one SSD (OCZ Vertex 2 100 GB) We want to evaluate the use of a L2ARC, so the current ZPOOL is: [CODE]... | Not sure why you're seeing the behavior you're seeing, but I can tell you why they don't necessarily signal terrible real world ZFS performance. Bonnie is designed to measure performance of the actual disks and intentionally tries to not leverage disk/memory cache. You're trying to use it to measure disk cache. It can ... | 6 | 9 | 4,352 | 2010-08-04T12:20:17.210 | infrastructure | serverfault.com | |
502,285 | Virtual network for reproducible tests | Im developing a software product that uses networking features like device bonding an multi-homing protocols. As with any protocol development, test-code needs to take latency, package-dropping etc. into account. I am therefore trying to create a virtual network environment in which I can do controllable, reproducible ... | Sounds like you want to use something like 'tc' (se http://www.linuxcommand.org/man_pages/tc8.html for more detail) on the various interfaces, using the 'netem' kernel component. An example would be: [CODE] See http://man.he.net/man8/tc for the manpage on 'tc'. See http://www.linuxfoundation.org/collaborate/workgroups/... | 1 | 0 | 427 | 2013-04-24T15:20:52.860 | infrastructure | serverfault.com | |
19,137 | Similarity between an n-dimensional curve and selected subsets of them | I'm asking here to get some advice. My goal is to detect similar patterns in an n-dimensional data. For example (extreme simple) you have two axes: X-Axis is Time (in seconds) and Y-Axis is Power (in Watt). So you get time-series with a specific pattern. My goal is to select a subset of the time-series and calculate th... | So let's start! First of all please have a look at the edit I made to your original question. It was not just an edit but implied important conceptual thing so I need to start with them: Graphs : Graph is a reserved term in mathematics for network-like objects. You better use the term Plot for sake of clarification. So... | 1 | 1 | 82 | 2017-05-23T09:30:01.837 | data_quality | datascience.stackexchange.com | |
30,906 | How do I use the unload command to export a table to a IXF file | For a table T in schema S, how do I use the unload command to export T data into a IXF file? The IBM DB2 documentation isn't very helpful for this simple case. I am trying to compare performance between the export command and the unload command. This is on DB2 9.7 for AIX | Ah ok. If you are referring to the UNLOAD command , that is only available on DB2 for z/OS. DB2 LUW does not have an UNLOAD command....except if you purchase IBM's separate product Optim High Performance Unload . (I am assuming you are wishing to use that?) Optim High Performance Unload uses the db2hpu command . And th... | 1 | 1 | 3,533 | 2012-12-21T13:44:27.897 | warehouse_errors | dba.stackexchange.com | |
414,414 | Production Disk Failure - Lucky it's sunday and out of hours (mdadm raid 5) | I have a production raid array that has hit problems. Luckily when I configured it I assigned a hot spare. Here is what the status looks like now: [CODE] If and when this completes however what do I need to do to replace the faulty drive as a new spare? Ideally I don't want to have to take the system down next week. | If your system supports hot-swap (sata, sas, ...) then you can do: [CODE] To remove the disk from the raid array md2. Later on when you have connected the new disk and partitioned it you can do: [CODE] To add it to the raid. | 2 | 2 | 204 | 2012-08-05T11:07:38.260 | infrastructure | serverfault.com | |
888,738 | Info about network adapters | If possible, can I get some informations about how to find out my network adapters and some more stuff about them, such as MAC addresses, their manufacturers, how can I find out which network adapter has an active connection and how many IP addresses do they have, in cmd! Thanks! | For the basics through ipconfig https://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/ipconfig.mspx?mfr=true For more advanced stuff you can use the Windows Networking Shell https://technet.microsoft.com/en-us/library/bb490939.aspx To map a MAC address to the manufacturers' OUI you may need to... | -3 | 2 | 69 | 2017-12-18T19:38:04.963 | infrastructure | serverfault.com | |
425,901 | Know when a resource has been fully consumed | I've got a race condition problem I need to solve with a distributed API/service and would appreciate vetting my plan and any fresh ideas I have missed. Problem: I have a finite amount of many (hundreds) different resource and need to know when each has been used up. The resources are consumed via API calls to a distri... | I see basically two types of approaches. One is to implement (what essentially amounts to) transactions. Have the distributed services contact (or go through) a central authority to check availability. Whether that is a traditional relational database, redis, ES, some single-instance service sitting on a queue, whateve... | 1 | 4 | 124 | 2021-04-29T14:23:31.993 | database_errors | softwareengineering.stackexchange.com | |
911,514 | Haproxy two processes are created by systemd | I have just compiled the latest [CODE] . [CODE] My service file looks as follows [CODE] But when I start service it creates two process like that [CODE] Should it work this way or I have invalid configuration? Thanks | two processes are created by systemd This is not correct. [CODE] creates one process and then haproxy forks (thereby creating another process). This is normal. One reason it is done is for security. haproxy starts as root and does the minimal setup work needed (bind to port 80, for example). It then forks and drops pri... | 0 | 1 | 2,931 | 2018-05-09T18:21:14.637 | infrastructure | serverfault.com | |
817,229 | Relay All mails of a domain with a SMTP server and store it | A customer have a domain on google apps and he wants to archive all the mail that come to the MTA server. I think that I can add a SMTP server to receive the email which would send all the emails to google apps, with postfix for example which would relay them and store it. is it the right solution ? How is possible to ... | It maybe more practical to setup the Google account to auto-forward all the emails it gets to a 'Archive' email address. Google Apps Email interface -> setting -> Forwarding -> 'Add a forwarding address' | 0 | 0 | 77 | 2016-11-26T17:44:12.160 | hadoop_errors | serverfault.com | |
684,810 | Postfix block internal communications | I'd like to know how to block my users to send mail to each other but give them chance to send and receive external mail. john@localdomain.com julie@localdomain.com REJECT john@localdomain.com tom@gmail.com OK julie@localdomain.com tom@gmail.com OK I've already tried to configure access restrictions rules like [CODE] B... | The configuration above (apparently from this page ) is used to allow internal-only communication and block the email from outside to internal. For your case, you need to modify it [CODE] | 0 | 2 | 365 | 2015-04-22T21:01:39.517 | infrastructure | serverfault.com | |
324,640 | Query performance on static, large PostgreSQL table | I tried to have this as detailed as possible. Sorry about the length! Background I created the following partitioned table [CODE] on a PostgreSQL (version 12.13) database: [CODE] I then created 51 partitions, each containing roughly 150 million lines (total lines 7.65 billion), based on the following template: [CODE] w... | Based on this: [CODE] has 1,000 unique values [CODE] has 7,500,000 unique values the pair [CODE] uniquely determines a row in the table Typical queries: (a) single SNP/protein queries (b) single protein, multiple SNPs queries (c) multiple proteins and multiple SNPs queries Table is read-only. I don't see the benefit of... | 4 | 10 | 971 | 2023-03-11T00:47:28.333 | api_errors | dba.stackexchange.com | |
293,989 | Necessary permissions to edit user details in AD | I need to delegate permissions to edit user information (phone numbers, address, etc) in AD. Its a 2003 domain. Ive already delegated: 'Read all user information' and 'Read, Write, Read and write general information, Read and write phone and mail options, read and write public information, read and write personal infor... | Oh, that sounds like AdminSDHolder protection. Check if inheritance is disabled for the users' ACLs, and/or check the value of the adminCount property on the objects. This occurs for users that are in (or sometimes, were once in ) one of the protected administrative groups. See here . | 2 | 2 | 647 | 2011-07-25T21:26:31.757 | infrastructure | serverfault.com |
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