Now using mysql
hi, have migrated from derby to mysql and all data seems to be retrievable and all is working ok...
1/. the existing mangodb folder... is that redundant? can it be deleted?
2/. when i go in system settings, its now unaware of database type and database size... is this normal?
3/. for scada jobs with 500 tags with per sample change logging, will mysql really make the system better? is there a point where derby can manage ok, then struggle?
4/. do the database purge facilities work ok whilst using mysql?
5/. will subsequent mango upgrades respect choice of external DB?
I have been also using MySql. Here are some I have noticed.
1/. Yes it can be removed
2/. Same here, it has been the way as long I know.
3/. No idea
4/. I have not faced any problem
5/. Seems working well. I started with v1.8 and have incrementally updated to v1.11 without issues.
Jokke is correct. Some additional info:
Mango cannot provide information about the size of the MySQL database because all it has is a url to a schema. Unlike Derby, it doesn't have a data directory that it can measure.
MySQL should provide better performance, yes. In most circumstances Derby is a perfectly fine database, but there are certain situations where MySQL provides vastly better performance. There have not been any noticeable cases where Derby is better than MySQL.
Yes, and in fact, this is one of the cases where MySQL is noticeably better.
Mango will continue to support both Derby and MySQL indefinitely. They serve competing needs: Derby is for convenience, MySQL is for performance.
just an update...
whilst using my project with conversion to mysql, i had need to delete an array of points within a soon to be redundant data source...
so i tried to delete the datasource and had errors about nested object, -1 from the browser in relation to the sql instance.
so i then proceeded to delete individual data points, which was successful, apart from one, which refused giving the same error.
i have now gone back to derby for the time being....
am i missing something, or is this a bug etc?
also, i'm noticing that my popup charts arent working now when the web server is viewed from a remote source...
i'll check the logs but i guess its trying to look up the derby database and struggling for some reason.
Do you have a more specific error message regarding why the point could not be deleted?
alas i dont, since i had to revert back to the derby setup as this job is in use.
it appeared to be pointed towards a failure to delete due to a nested object failure giving a -1 error.
baslically i'd converted a 150mb derby db to sql.
this project had about 2 dozen data sources, one of which i no longer needed.
i attempted to delete the data source (deleting all the tags at the same time) and it failed with this nested -1 failure).
so i then proceeded to delete tags withing the container instead.... which was ok unitl i got to this particular tag... and this still prevented me from deleting the data source too..
so for the time being i'm using derby again.
Ok. Unfortunately your description doesn't ring any bells. If you ever produce the error again, let me know.