get the pid before stopping in optimize script

[glguy]

Gets the PID before stopping fuseki so that it can tell if the stopping succeeded.

When I test this it successfully stops the service, however I'm getting an error from tdbstats that that doesn't seem related to my change.

Stopping Fuseki
Running tdbstats
org.apache.jena.sparql.ARQException: No such type: <http://jena.apache.org/2016/tdb#DatasetTDB2>
	at org.apache.jena.sparql.core.assembler.AssemblerUtils.build(AssemblerUtils.java:140)
	at org.apache.jena.sparql.core.assembler.AssemblerUtils.build(AssemblerUtils.java:132)
	at tdb2.cmdline.ModTDBDataset.createDataset(ModTDBDataset.java:81)
	at arq.cmdline.ModDataset.getDataset(ModDataset.java:35)
	at tdb2.cmdline.CmdTDB.getDataset(CmdTDB.java:77)
	at tdb2.cmdline.CmdTDB.getDatasetGraph(CmdTDB.java:69)
	at tdb2.tdbstats.exec(tdbstats.java:94)
	at org.apache.jena.cmd.CmdMain.mainMethod(CmdMain.java:87)
	at org.apache.jena.cmd.CmdMain.mainRun(CmdMain.java:56)
	at org.apache.jena.cmd.CmdMain.mainRun(CmdMain.java:43)
	at tdb2.tdbstats.main(tdbstats.java:43)
Now printing the contents of stats.opt:
cat: /etc/fuseki/databases/RACK/stats.opt: No such file or directory

[weisenje]

This is most likely fallout from updating to TDB2 (#951) @tuxji

[tuxji]

This is most likely fallout from updating to TDB2 (#951)

I agree. Likely you tested with an old RACK still using tdb, but your cli/optimize.sh is already running tdb2.tdbstats.

[glguy]

OK, that makes sense. I have to manually rebuild my rack docker image to get the aarch64 build, so I'm not always on the latest revision there. In that case I think this change is ready to go.

[weisenje]

I tested via the Docker RACK UI and am seeing consistently successful restarts and optimizations.

@glguy Just checking that you do not also want to make the same change in restart-fuseki.sh as you made in optimize.sh? These have mirrored each other in the past.

[glguy]

We either need them in both places or neither places. It's possible that something has changed and fuseki restarts fine on its own now, but also it's easy for the restart script to report no error and not actually restart anything.

[weisenje]

Got it - so you will make restart-fuseki.sh match optimize.sh?