Re: Video Tutorial - How to Build and Install PL/Java

On 3/5/2016 11:23 PM, Chapman Flack wrote:
> it would be much safer if you showed cloning the repository
> and then checking out the *actual release tag*:
>
> git checkout V1_5_0b2
>
> or without using git, by downloading the .zip or .tar.gz from
>
> https://github.com/tada/pljava/releases
OK, I can do that
> The next thing, later on, you gave the CREATE EXTENSION pljava;
> command, and it worked ... *then* you showed setting libjvm_location.
did you see my pull request at
https://github.com/tada/pljava/pull/97/files ?
> It must have been set correctly already, or the CREATE EXTENSION
> would have failed. Probably in your earlier experimenting you saved
> the correct value with ALTER DATABASE, or by editing the conf file?
> (I think the saved value is the same as the one you gave in the SET
> command, otherwise that command would have failed ... it doesn't
> let you change libjvm_location in a session where the jvm has already
> loaded, because it would be too late to make any difference to that
> session.)
while playing with this before I tried both ALTER DATABASE and ALTER SYSTEM
to set that value. unfortunately I was unable to UN-SET that value? I
tried ALTER - RESET
but that didn't seem to work
> So if you wanted to make that part of the video even more helpful,
> you could also show what CREATE EXTENSION does if you do *not* have
> the value correctly set first, and how you can tell what happened and
> recover by setting the variable. That will be very helpful to people
> who do try CREATE EXTENSION without the right variable setting, and
> wonder what the error messages mean. :)
>
> Then you could also show how to save the correct setting for later
> sessions, using a command like ALTER DATABASE postgres SET
> pljava.libjvm_location FROM CURRENT.
so you want me to show the "pitfalls" and troubleshooting? I want to
keep the video
rather short. replacing git with download can save some time so it
might be offset,
but I really prefer to keep the whole thing under 15 minutes
> It is nice to show the examples.ddr file, but it might also be good
> to mention those are not *all* the function definitions, in fact that
> file is only still there because not all examples are converted to
> use Java annotations yet, and it contains only the ones that haven't.
> It will be getting smaller and smaller....
>
> ... so you might want to also show how to list the functions with
>
> \df javatest.*
> or for more detail (including the description, where present)
> \df+ javatest.*
>
> You could also show how to see the full SQL syntax for one function's
> declaration, like
>
> \sf javatest.java_addone
>
> Wildcards don't work with \sf, just one function at a time.
OK, much of this is very new to me. I have very little experience with
PostgreSQL, psql, PL/java, etc.
> Browsing on github for the examples.ddr file, you could also show
> browsing the directory of example sources, or the subdirectory
> annotation, containing the examples that already have been converted
> so you do not see them in examples.ddr.
>
> Also, when browsing files on github, you could show how to start on
> the releases page and click the tag for the release you have installed,
> and then browse files, so that you know you are seeing the same versions
> you are actually running. :)
sure, I can show the local files instead of the github repo in the browser
> I know those are a lot of comments, so if it didn't quite come through,
> I really like the video, thanks for making it! The suggestions are for
> making it even better.
thank you. I'll try to re-do it with these points in mind.

can you please explain:

1) how do I unset the value

2) where are the docs for the `sqlj` namespace (or is it a schema?), for
example, what do the additional args do exactly?

SELECT
sqlj.install_jar('file:/C:/Apps/pgsql951/share/pljava/pljava-examples-1.5.0-BETA2.jar',
'examples', true);

and this one? creates a schema named javatest and maps it to the
'examples' namespace from the previous command?

SELECT sqlj.set_classpath('javatest', 'examples');

thanks,

Igal