How do I write a pandas dataframe to Vertica?

Question

I have some data set in a pandas data frame that I wish to write to Vertica. I've already created my table using the vertica_python library. What is the best way to write my data frame to Vertica?

Answer 1

Often when connecting to Vertica, you can use Postgresql as a stand-in since certain parts of Vertica were originally based on Postgresql.

from sqlalchemy import create_engine
engine = create_engine('postgresql://user:pass@host:5433/MYDB')
df.to_sql('table_name', engine)

If this doesn't work you could try out the vertica-sqlalchemy package.

Also, depending on the SQL created (and if the ODBC driver converts INSERT to a COPY) this might be very slow. If you find that it is doing lots of individual inserts on the database, you'll probably want to switch to a COPY method where you create strings and COPY FROM STDIN to make it faster.