MySQL workbench is a fantastic tool. However, I'm having a hard time figuring out how to create multiple windows. For example, in Sequel Pro (or TablePlus or really any other SQL client) I can have multiple windows:
Yes I know there are 'tabs' but those aren't quite the same thing. Is there a way to have multiple windows using MySQL Workbench?
It seems like from a few other threads this would need to be done manually via:
$ open -n -a MySQLWorkbench.app
MySQL Workbench is originally designed to be a single instance app only. On Windows this has been extended to allow multiple instances (there's a setting in the preferences) and you found a way to do this on macOS. However this bears some risks, because all instances share the same config and cache files and can write simultaneously to them, which is prone to file corruption. Also, any changes done to the configuration or connections end up in the same file, so the last change may override previously made changes in another instance.
Related
I want to use Postgresql in Windows Server 2012 R2 for one our project where it can be 24/7 uptime.
I would like to ask the community if I can have 2 master instances in 2 different servers A&B and they will 'work' on the same DB located in a shared file storage in lan. Always one master instance on server A will be online and when it goes offline for some reason (I suppose) a powershell script will recognize that the postgresql service stopped and will start the service in server B. The same script will continuous check that only one service in servers A & B is working to avoid conflicts.
I'd like to ask if this is possible or a better approach for my configuration.
(I can't use replication because when server A shuts down the server B is in read-only mode thing that I don't want)
If you manage to start two instances of PostgreSQL on the same data directory, serious data corruption will happen.
Normally there is a postmaster.pid file that prevents that, but a PostgreSQL server process on a different machine that accesses the same file system will happily unlink that after spewing some log messages, thinking it was left behind from a crash.
So you are really walking on thin ice with a solution like that.
One other issue that you didn't think of is that script that is supposed to check if the server is still running. What if that script fails, because for example the network connection between the two servers is down, but the server is still up an running happily? Such a “split brain” scenario will cause data corruption with your setup.
Another word of caution: since you seem to be using Windows (Powershell?), you probably envision a CIFS file system when you are talking of shared storage. A Windows “network share” is not a reliable file system — last time I checked, it did not honor _commit.
Creating a reliable failover cluster is harder than you think, and I'd recommend that you check existing solutions before you try to roll your own.
We have an application which is using Cassandra for its database. How should we deploy schema changes in a live production environment.
In development we are just blowing the database away and recreating it with a 'database.cql' script kept in version control. This clearly isn't a solution in production.
In the relational world I would either use a sequence of upgrade scripts and apply them in order, or use a tool to interactively compare the staging and production databases and make the appropriate schema changes.
How do I solve the same problem in the Cassandra?
Here's one I've started and have been using for a while.
https://github.com/heartysoft/aedes
It supports multiple environments, and versioning. Since we're Windows based, it's mainly powershell, but there's no reason a bash script couldn't be written to do the equivalent. The powershell script itself is extremely simple. It requires Powershell v3+. Usage is pretty easy:
aedes.ps1 192.168.40.4 [-u username -p password -env dev]
will look for schema files in the ..\schema folder. Schema files are expected to have a n_ prefix. Environment specific files have a .env.cql postfix. So, if the files are:
1_people.dev.cql
1_people.prod.cql
2_people_some_indexes.cql
3_jobs.dev.cql
3_jobs.prod.cql
4_jobs_something_changed.cql
And run it for prod, then the ones with .prod.cql and no "env" .cql will be applied in order. You can also specify a $start version that can be used to specify where to start applying from (e.g. if start is specified as 3, then anything with 1_ and 2_ will be skipped).
It's pretty basic but seems to work quite well. We just have Cassandra downloaded (not installed) on the "applier machine" (which could be your machine, i.e. not part of a cluster) and have cqlsh on the PATH for easier application. Did (and do) have plans for more features, but working nicely as is for the time being.
Since there wasn't an existing tool, I ended up writing one.
It is called cql-migrate, and provides incremental updates to a deployed Cassandra schema.
[update] Since writing this, I have found a couple more options: one for for rails and another for go
I'm going to build a extremly small script for dumping a Sybase database in perl. The problem is that Perl doesn't come with preinstalled Sybase-support. I don't have access to the servers root so I can't install any packages and I can't reach the perl-folder. The server is not configured for internet access so I have to deliver the packages "manually" thorugh FTP.
So, my question is if there are any easy ways of doing this. The only library I need is DBI::Sybase or Sybase standalone (maybe I haven't done my research enough and doesn't even need this much?) which means I would love to just be able to put the .pm file there, loading it through
use localModule
and then run my small script.
The solution has to work on both Red hat and Solaris if I understood my supervisor correctly.
Best regards
Since you are primarily concerned with dumping the database, and not data retrieval and manipulation, you could probably get by without having to use DBI::Sybase or other perl module that is not preinstalled.
Without more details, it's hard to be very specific, but here's the overview. Your perl script can execute some SQL scripts which can dump the databases.
You can either put the list of databases you wish to dump in a config file (or env file), or you can generate it dynamically by calling isql using the -b option to suppress headers, and nocount to suppress footers, and store the output in an array.
Once you have the list of databases, just loop them, running another isql command to dump each database.
Lets say I have an Emacs-Server running on some remote server, with all the libraries and software necessary for running my application.
Then I want several clients to connect to that remote machine, using Emacs-client. Does each client need a full Emacs installation, or is there a minimal installation that is just enough to communicate with the remote server, where all the action is?
Could this (Emacs-)client installation be so minimal, that almost all software-updates can be done on the server, without affecting the Emacs-clients?
Is there a reason not to run the clients remotely as well, and simply use a local display? That way, pretty much all you need on the local machines is the ssh client and the X Window server.
ssh -X (user)#(server) "emacsclient -c"
Edits for the comments:
This command starts a new client to connect to an existing Emacs server (which it assumes is already running). You can use "emacsclient -a '' -c" to automatically start emacs --daemon if there is no existing server, but I don't know whether you want the connecting user to be starting the server.
In fact, I'm pretty unsure about the whole multi-user side of this to be honest, as I've never done that before. Authentication for the above is handled by ssh, but there may well be subsequent permission issues to deal with, or similar, when the server and the clients are started by different users.
This approach should be possible with Windows/Cygwin as client and/or server, as Cygwin provides Emacs, OpenSSH, and X.org packages. (I regularly use Windows/Cygwin as a local display for Emacs running on Linux.) It may be harder to set up, though, and any permissions issues are probably different when you're using Cygwin.
I'm less sure how this would work without Cygwin. NTEmacs certainly won't talk to X.org, so I imagine you'd be terminal based in that instance. (There are probably other options, but Cygwin sounds to me like the best-integrated approach to using all of Emacs, SSH, and X on Windows).
Lastly, I imagine you're probably getting your "Connection refused" error because localhost is not running a sshd daemon? I would say that configuration of ssh is outside the scope of this question, but there are lots of resources online for that.
Depending on what you're trying to achieve, you may be able to use a combination of Emacs and Screen. By starting up Emacs from Screen on the remote machine and detaching from it, you can subsequently re-attach from a different machine that doesn't have Emacs. Again, whether this will work for you or not depends on what you're trying to do; however, for many Emacs use-cases, this can be very effective. If you're not familiar with using Screen in this manner, here is some reading material:
screen - The Terminal Multiplexer
I am not sure that would be possible. emacsclient uses tramp to connect to a remote server, and just by looking at the number of requires in the tramp elisp files (41) it seems very unlikely. You can try it yourself with the following:
zgrep -oE "\(require '[a-z-]+\)" *el.gz | sed -e 's%[a-z0-9-]\+\.el\.gz:%%g' | sort | uniq -cu | wc -l
I'm not an expert in emacsclient, but I don't think is was designed to do what you're looking for. I think the general use case is that emacsclient allows you to redirect new requests to open a file with emacs to a persistent emacs process to avoid what may be a bit of an overhead in startup time. You seem to be looking for more of a true client/server relationship.
I think to meet the goal you're aiming at you'll probably need to look a little outside emacs, probably a project unto itself - 'emacsRemoteClient. It boils down to one or two models; the file you want to edit would need to have it's path sent over to the server machine so that emacs could do some sort of remote tramp access & then spawn the xwindow locally (using the local X env or requiring an x server on windows)... or two, transferring the file to some temp location on the server box and again spawning the remote x window locally (followed by syncing the changes between the tmp & local file).
Would be cool to have something like that... but suspecting it'll involve a bit of work. Maybe we just need a version of emacs written in javascript and it can live in the cloud or on your browser... oh to have emacs keybindings in the browser ;-)
-Steve
ASP.NET Membership is just great as there are a ton of functionality right there to be used, and we don't need to change nothing at all.
We can even create our own Provider based on Membership database, and that give us infinite possibilities, like as I don't like the Question/Answer I just use an email that is sent with a reset link.
But this is all done with SQLEXPRESS .mdf file and I wanted to use my own Database for this so I can use SQL Server Enterprise as we have in the Office and not the Express Edition.
How can I easily use the ASP.NET Membership tables in my own Database?
I rememebered some years ago that we needed to use aspnet_reg (something) to create the correct tables, but I can't find that info anymore.
I also tried to use other Membership Providers, namely Altairis.Web.Security from CodePlex and saw the Chris Pels Video on creating a new Membership Provider
On Altairis solution, the Model is not complete and lack several points such as Several Applications as it's made to be used with only one, and Chris Pels contains to much Store Procedures that I need to create by hand.
I'm for given Chris code a go but I just wanted to know if there would be available something easier.
All this is to be integrated in ASP.NET MVC 2 Web Application.
Thanks
You have 3 options:
Do it by running aspnet_regsql.exe: Just open "Start Menu>All Programs>Microsoft Visual Studio 2010>Visual Studio Tools>Visual Studio Command Prompt(2010)" and then type aspnet_regsql. A wizard appears and let you select your desired database.
Do it via API: Use System.Web.Management.SqlServices class and its Install and Uninstall methods. This will programmatically install/uninstall database artifacts.
Do it manually: Go to C:\Windows\Microsoft.NET\Framework\v4.0.30319 or something like. You will find 9 .sql files that begins with Install and 9 .sql files that begins with uninstall. You can run them manually in your database to create needed tables/store procedures/etc. But consider changing database name in sql scripts. Default db name is aspnetdb.
It's aspnet_regsql
Under the following path:
C:\windows\Microsoft.NET\Framework\v4.0.30319\aspnet_regsql
You need to open up the Visual Studio Command Prompt, navigate to C:\WINDOWS\Microsoft.NET\Framework\\aspnet_regsql.exe . Some example are located in the MSDN documentation.
Example: aspnet_regsql.exe -E -S localhost -A mr - installs the database elements for membership and role management on the local computer running SQL Server using Windows authentication.