def perf_uris():
"""Test strategies for making lots of additions and lookups to the
`history_uri` table quick.
Cases:
- How much does history_uri_uri index help?
Answer: Not at all, because the "UNIQUE" constraint on `uri` results
in an automatic index of the same kind.
- Does caching uri id's in add_or_get_uri help?
Yes, spectacularly.
- TODO: What is the impact of NOCASE collation on `uri`?
"""
import random
db_path = join("tmp", "perf.sqlite")
if False:
if exists(db_path):
os.remove(db_path)
assert not exists(db_path)
db = Database(db_path)
# Our working-set files.
ws = ["file:///home/trentm/%s.txt" % s for s in "abcdefghijklmnopqrstuvwxyz"]
# Preload db with a lot of files.
if False:
print "Setting up db..."
uris = ["file:///home/trentm/%05d.txt" % d for d in range(5000, 10000)]
random.shuffle(uris)
for uri in uris:
db.uri_id_from_uri(uri)
print "Done setting up db."
rand = random.Random(42)
randchoice = rand.choice
M = 3
times = []
for j in range(M):
N = 1000
start = timestamp()
for i in range(N):
uri = randchoice(ws)
id = db.uri_id_from_uri(uri)
end = timestamp()
times.append(end-start)
for t in times:
print "%d add/gets: %.3fs" % (N, t)
