How can use the hstore extension type when migrating OSM data to PostGreSQL?

Question

I am trying to migrate some Open Street Maps .osm.pbf file to my postgresql database using osm2pgsql on an ubuntu machine.

When I inspect the data after the process has been finished, the column for tags is types as text[] and filled with data like this:

{highway,residential,lit,yes,name,"St. Nicholas Street",name:en,"Saint Nicholas Street",name:mt,"Triq San Nikola"}

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Question 1:

• Is that an hstore type data? I can't seem to query it as if so. I tried this format:

SELECT * FROM planet_osm_ways WHERE tags ? 'highway' LIMIT 20;

yealding this error:

ERROR:  operator does not exist: text[] ? unknown
LINE 1: ...T *, tags as tags FROM planet_osm_ways WHERE tags ? 'highway...

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Question 2:

• So assuming the error and format above means that the data was simply not saved as an hstore typed data, how can I correct my migration process to fix this?

My process:

1. Create a new database using pgAdmin 3 on linux ubuntu.
2. add hstore extension to database (pgAdmin)
3. add postgis extension to database (pgAdmin)
4. super user into postgres user in terminal

osm2pgsql -c -d <DB_NAME> <FILE_PATH> --slim --hstore --multi-geometry

5. run migration command:

sudo -u postgres -i

That's it, osm2pgsql does it's thing and gives out a successful output.

So what am i missing in this process?