Global search is slow for some search terms

[osma]

At which URL did you encounter the problem?

http://dev.finto.fi/fi/search?clang=fi&anylang=on&q=b%C3%B6cker&vocabs=
http://dev.finto.fi/fi/search?clang=fi&anylang=on&q=suunnittelu&vocabs=

What steps will reproduce the problem?

1. Perform global search, in any language, for "böcker" or "suunnittelu"

What is the expected output? What do you see instead?

The query can take a very long time, over 10 seconds.

This happens both in the 1.3-maintenance version (finto.fi) and in current master (dev.finto.fi).

The problem is unrelated to #371.

Should investigate what causes the delay.

[osma]

The problem is not the underlying queryConcepts query. These take around 100ms:
http://dev.finto.fi/rest/v1/search?query=b%C3%B6cker*
http://api.finto.fi/rest/v1/search?query=b%C3%B6cker*

[osma]

This query for "böcker" from 12 vocabularies returns just the YSO concept 12 times and takes about 5 seconds:
http://dev.finto.fi/fi/search?clang=fi&anylang=on&q=b%C3%B6cker&vocabs=keko+kto+kulo+liito+maotao+mero+pto+puho+tero+tsr+valo+yso

If I cut it down to 6 vocabularies it takes about 2.5 seconds:
http://dev.finto.fi/fi/search?clang=fi&anylang=on&q=b%C3%B6cker&vocabs=keko+kto+kulo+liito+maotao+mero

So the problem seems to be related to displaying the YSO concept. Each time takes about 400 ms.

[osma]

It's not the SPARQL queries. They take about half a second total. PHP CPU usage is high during the execution.

[osma]

After the above commit the main culprit is now Concept->getProperties which takes about 200 ms per concept.