We have a transactional replication set and we want to change CommitBatchThreshold but couldn't find a proper documentation on how to change it. Would adding '-CommitBatchThreshold 10' to the Steps would work in Agent Properties?
Wanna be sure before changing everything.
Yes, adding the parameters and parameter values to the Steps page in the Agent Properties will work. Note that if you are running the Distribution Agent continuously then you will need to restart the replication agent for the changes to take affect.
Related
I have an SQL file containing several commands, when I need to make a correction to my application database that the application can't yet do, I use DBVis to select and execute the command I need (e.g. to delete an incorrect entry). Problem is, the button to run the whole page is right next to the button to run a selected command. So I just dropped and re-created my table, losing all my data. Is there a way to undo this?
I'm looking to either 'undo' each command until I get back to the right place, or revert back to yesterday, where I know everything was correct.
Thanks!
Yes, you can if...
your administration tool did set autocommit=OFF by default, you can
just execute a ROLLBACK (or just shutdown your administration tool)
If latter doesn't work, check if your binary log was enabled, and restore with mysqlbin log tool
If none of the above mentioned solution works, use your (probably not existent) backup for restoring
We use Liquibase as database refactoring tool in a cloud service, and would now like to employ it to do some lightweight data migration, which would be realized as CustomTaskChange and would take just a few seconds. This data migration is 'nice to have' but it is by no means mandatory for the service to function properly - if it fails for some reason, the change set should just be skipped, the service started nevertheless, and the change set retried during the next restart of the service until it finally succeeds. So, errors when executing the change set should be ignored but the set marked as ran only after it actually ran successfully once.
We wonder how we could implement this kind of behavior using Liquibase: The <changeSet> attribute failOnError="false" continues in case of an error but according to documentation and an answer given by Nathan Voxland here at StackOverflow it always marks the change set as ran - hence Liquibase wouldn't retry to execute it during the next startup of the service. The <preConditions> attribute onFail seems to be concerned only with failing preconditions so startup would still fail in case of an error when setting onFail to, say, CONTINUE.
Is there any other option / attribute that we overlooked or a recommended fashion to solve this kind of situation?
You may be able to achieve the "retry until successful" behaviour if you implement the optional data migration inside the code of a custom precondition. Then, you could configure onFail of that precondition to CONTINUE which will give you the behaviour you want (source):
CONTINUE – Skip over the change set. Execution of the change set will be attempted again on the next update. Continue with the change log.
I'm not entirely sure if implementing the migration in the precondition code is technically possible – because it certainly wasn't meant for such things. And you also may want to verify that the custom precondition is not executed again once the patch set has been marked as ran.
I have an internal Apache server for testing purpose, not client facing.
I wanted to upgrade the server to apache 2.4, but there is no space left, so I was trying to delete some files on the server.
After checking file size, I found a folder /var/lib/elasticsearch takes 80g space. For example, /var/lib/elasticsearch/elasticsearch/nodes/0/indices/logstash-2015.12.08 takes 60g already. I'm not sure what's elasticsearch. Is it safe if i delete this logstash? Thanks!
Elasticsearch is a search engine, like a NoSql database, and it stores the data in indeces. What you are seeing is the data of one index.
Probobly someone was using the index aroung 2015 when the index was timestamped.
I would just delete it.
I'm afraid that only you can answer that question. One use for logstash+elastic search are to help make sense out of system logs. That combination isn't normally setup by default, so I presume someone set it up at some time for some reason, and it has obviously done some logging. Only you can know if it is still being used, or if it is safe to delete.
As other answers pointed out Elastic search is a distributed search engine. And I believe an earlier user was pushing application or system logs using Logstash to this Elastic search instance. If you can find the source application, check if the log files are already there, if yes, then you can go ahead and delete your index. I highly doubt anyone still needs the logs back from 2015, but it is really your call to see what your application's archiving requirements are and then take necessary action.
In my project I am trying to do the setting where in I can update the dynamic properties in the server/application without even restarting it.
We face this problem that whenever we have to update or change some properties which are dynamic in nature, then every time we have to restart the server/application and this results in unavailability of the server for that time stamp.
I have already found one tool Archaius-ZooKeeper to set it.https://github.com/Netflix/archaius/
We are trying to do it for JBoss servers where we use war file to deploy on server.
Please suggest are there any other method or tool or technology that can be used to set it.
Thanks in advance.
You could consider jRebel, allows you to redeploy your app without any downtime, then you can use jRebel Remoting to redeploy from eclipse to a remote server
You may use Zookeeper. You have to create a Znode and add the properties in the Znode. All your servers/applications should read from this Znode and also put an watch on this Znode for data changes.
Alternately, you may use a database to store the properties along with their modification time. Whenever you change the value of a property, the corresponding modification time is changed. All your applications/servers keep pulling the delta at some intervals (may be 2 secs/ 5 secs etc.).
Or you may have the properties hosted on a web server, or on NFS, or on some distributed cache etc. All your applications/servers keep reading it at some intervals for detecting any changes.
You can use Spring Cloud Zookeeper. I shared a little example here.
I'm writing a WLST script to deploy some WAR's and an EAR. However, intermittently, the script will time out because it can't seem to get an edit lock (this script is part of a chain of many other scripts). I was wondering, is there a way to override or stop any current locks on the server? This is only a temporary solution, but in the interest of time, it will do for now.
Thanks.
You could try setting a wait period and timeout:
startEdit([waitTimeInMillis], [timeoutInMillis], [exclusive]).
Are other scripts erroring out, leaving the session locked? You could try adding exception handling around those. Also, if you have 'Automatically acquire lock" enabled in the Admin Console and you use the admin console sometimes it can cause problems if you are running scripts at the same time, even though you are not making "lock-requiring" changes.
Also, are you using the same user for the chained scripts?
Within WLST, you can pass a number as a parameter to gain an exclusive lock. This allows the script to grab a different lock than the regular one that's used whenever an administrator locks from the console. It also prevents two instances of the same script from stepping on each other.
However, this creates complex change merge scenarios that are best avoided (by processes).
Oracle's documentation on configuration locks can be found here.
Alternatively, if you want the script to temporarily relieve any existing locks regardless of the pending changes, you may as well disable change management from the console, minimizing the inconvenience caused.
WLST also contains the cancelEdit command that you could run before you startEdit. Hope one of these options pan out!
To take the configuration change lock from another administrator:
If another administrator already has the configuration lock, the following message appears: Another user already owns the lock. You will need to either wait for the lock to be released, or take the lock.
Locate the Change Center in the upper left corner of the
Administration Console.
Click Take Lock & Edit.
Make your configuration changes.
In the Change Center, click Activate Changes. Not all changes take
effect immediately. Some require a restart (see Use the Change
Center).
As long as you're running WLST as an administrative user, you should be able to jump into an existing edit session with the edit() command - I've done a quick test with two admin users, one in the Admin Console, and one using WLST, and it appears to work fine - I can see the changes in the Admin Console session inside the WLST interpreter.
You could put a very simple exception handler around your calls to startEdit that will log the exception's stack trace, but do nothing else. And then rely on the edit call to pop you into the change session.
Relying on that is going to be tricky though if another script has started an edit session and is expecting to be able to commit that change session itself - you'll be getting exceptions and unreliable behaviour across multiple invocations.