[Koha] Opac not searchable after upgrading database from Koha 3.18 to 19.11

[Quỳnh Vũ Đỗ]

Hello everyone

After upgrading a Koha database from version 3.18 to 19.11, I was not able
to log in in the staff/administration of Koha as I obtained a "Software
Error" message. However, I was able to get to the OPAC page (at
http://localhost:8000/) but any search returned nothing.
I checked with Phpmyadmin that the biblio table of koha_library was
effectively filled with the data of the 3.18 database (which it was), but
the search of strings that were present returned nothing.

Does someone have encountered that problem and knows the solution?
I am thinking of running in a terminal the command "koha-rebuild-zebra" but
I prefer to listen to some sound advice first.

Thanks for reading
Quynh
=================
M. Vũ Đỗ Quỳnh (Ph.D)
Trường Đại học Thăng Long - Université de Thang Long - Thang Long
University (Hanoi, Vietnam)
Phó Hiệu Trưởng, phụ trách HTQT - Vice-recteur chargé de la coopération
internationale - Vice-Rector in charge of International Cooperation
Web: http://thanglong.edu.vn/