The annual "Free and Open Source Software for Geospatial" (FOSS4G)
conference is the largest global gathering focused on open source
geospatial software. Regularly attracting over 1,000 attendees, FOSS4G
brings together developers, users, decision-makers and observers from
a broad spectrum of organizations and fields of operation.
PostgreSQL and PostGIS are common denominators throughout the FOSS4G
program, and the conference Call for Papers is currently open.
https://2020.foss4g.org/speakers/
Due to the popularity of PostGIS, PostgreSQL is the mostly frequently
used database in the open source geospatial world, and talks about
general purpose PostgreSQL operations as well as PostGIS-specific use
cases are always appreciated.
If you submit before February 4, your paper will be eligible for early
acceptance, so consider submitting soon.
https://2020.foss4g.org/early-acceptance/