Fixes #3906 - Fix migration script in order to migration eventlogs from version 1

[nperron]

Fixes #3906 - Fix migration script in order to migration eventlogs from version 1
Ref http://www.rudder-project.org/redmine/issues/3906

[jooooooon]

This makes sense to me, and looks valid from a shell scripting point of view, but I don't understand the logic behind it. I'd rather @fanf did the Technical Review.

[fanf]

The logic is ok: we want to find the lowest "fileformat" and set it in the migration column in our database.
But it seems to reapeat itself A LOT:

• all request are the same modulo the fileformat number;
• content of the different migration files are the same modulo the number setted in the column
• for each new fileformat added, then a new variable+elif+same sql file has to be created.

Can't we do something like
FILEFORMAT=""
for i in 2 1 do
RES=$(su - postgres -c "psql -t -d rudder -c "select count() from (select xpath('/entry/[@fileformat=${FILEFORMAT}]',data) AS x from eventlog) as Y where array_upper(x, 1) > 0;"")
if [ $RES -ne 0 ]; then FILEFORMAT=$RES; fi
done

And then give the result of FILEFORMAT as input for the SQL update script (if non empty) ?

[nperron]

Pull Request updated

[fanf]

Seems good! Thanks