I am kind of confused about the behavior of psycopg2 cursor fetchmany method compared with paging query
Say, I have a query that will get 10000 rows in total.
When I use fetchall, I understand that the 10000 rows will be fetched back to the python process in one round.
But when I use fetchmany and the fetch size is 3000, then it will perform 4 times to get back all the 10000 rows (3000*3+1000),does the psycopg2 cursor will kick off 4 queries like the paging query does or only one query is performed but the db server is prepared for the data to be transferred in 4 rounds?
I want to use fetchmany, but I don't like the many rounds query.
Could some one help explain, thanks.