Performance

=== Reusing objects ===

Most of the API functions (like add_condition(...) or get_condition(...)) can accept model objects as parameters:

# 1. Using run number and condition name db.add_condition(1, "my_value", 10)

2. Using model objects

run = db.get_run(1) ct = db.get_condition_type("my_value") db.add_condition(run, ct, 10)

When you do db.add_condition(1, "my_value", 10) condition type and run are queried inside a function. If you do several actions with one object, like adding many conditions for one run or adding one condition to many runs, reusing the object could boost performance up to 30% each.

=== Auto commit value addition=== Performance study shows, that approximately 50% of the time spent in add_condition(...) is used to commit changes to DB.

To speed up conditions addition add_condition(...) function has '''auto_commit''' optional argument. By default it is '''True''', changes are committed to DB, if ''add_condition'' call is successful. Setting ''auto_commit''='''False''' allows to defer commit, changes are pending in SQLAlchemy cache and can be committed manually later.

''auto_commit''='''False''' purposes are:

• Make a lot of changes and commit them at one time gaining performance
• Rollback changes

To commit changes, having db = RCDBProvider(...) you should call db.session.commit()

""" Test auto_commit feature that allows to commit changes to DB later""" ct = self.db.create_condition_type("ac", ConditionType.INT_FIELD)

Add condition to addition but don't commit changes

self.db.add_condition(1, ct, 10, auto_commit=False)

But the object is selectable already

val = self.db.get_condition(1, ct) self.assertEqual(val.value, 10)

Commit session. Now "ac"=10 is stored in the DB

self.db.session.commit()

Now we deffer committing changes to DB. Object is in SQLAlchemy cache

self.db.add_condition(1, ct, 20, None, True, False) self.db.add_condition(1, ct, 30, None, True, False)

If we select this object, SQLAlchemy gives us changed version

val = self.db.get_condition(1, ct) self.assertEqual(val.value, 30)

Roll back changes

self.db.session.rollback() val = self.db.get_condition(1, ct) self.assertEqual(val.value, 10)

The example is available in tests:

$RCDB_HOME/python/tests/test_conditions.py

(!) note at the same time, that more complex scenarios with not committed objects haven't been tested.