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@mlissner
mlissner / queryset_generators.py
Created March 10, 2012 04:13 — forked from dbrgn/queryset_generators.py
Adds a date-based queryset generator
from datetime import datetime
from datetime import timedelta
def queryset_generator(queryset, chunksize=1000):
"""
Iterate over a Django Queryset ordered by the primary key
This method loads a maximum of chunksize (default: 1000) rows in its
memory at the same time while django normally would load all rows in its
memory. Using the iterator() method only causes it to not preload all the
WITH table_scans as (
SELECT relid,
tables.idx_scan + tables.seq_scan as all_scans,
( tables.n_tup_ins + tables.n_tup_upd + tables.n_tup_del ) as writes,
pg_relation_size(relid) as table_size
FROM pg_stat_user_tables as tables
),
all_writes as (
SELECT sum(writes) as total_writes
FROM table_scans