diff options
| author | ZhiQiang Fan <aji.zqfan@gmail.com> | 2015-10-24 09:30:53 -0600 |
|---|---|---|
| committer | ZhiQiang Fan <aji.zqfan@gmail.com> | 2015-11-09 00:12:41 -0700 |
| commit | 14586b2eac909dd76431e4eb9ff00b8f5a4c2d0c (patch) | |
| tree | 61a9e6d88de028080bd250731ba5dbfb9dff253f | |
| parent | 72a57fab8112eda4331fb7d624c82e0e1e5f8df8 (diff) | |
| download | ceilometer-14586b2eac909dd76431e4eb9ff00b8f5a4c2d0c.tar.gz | |
avoid unnecessary inner join in get_resources() for SQL backend
To get distinct resource ids, we do a query on resource table which
inner join sample table, and apply filters on it.
Note that when sql_expire_samples_only is enabled, there will be
some resources without any sample, in such case we must use inner
join to avoid wrong result, no matter if there is a timestamp filter
or not.
But that option is disabled by default, so when there is no timestamp
filters, the inner join is unnecessary, we should avoid it to save
some RAM/CPU cost.
Change-Id: If85dbea15d42d42c6b0be7402c06f258e278b2eb
Closes-Bug: #1509677
(cherry picked from commit a4f442940551a8a38e26e132c7efa766226daa15)
| -rw-r--r-- | ceilometer/storage/impl_sqlalchemy.py | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/ceilometer/storage/impl_sqlalchemy.py b/ceilometer/storage/impl_sqlalchemy.py index 856ce7d9..5a60a98a 100644 --- a/ceilometer/storage/impl_sqlalchemy.py +++ b/ceilometer/storage/impl_sqlalchemy.py @@ -432,9 +432,16 @@ class Connection(base.Connection): session = self._engine_facade.get_session() # get list of resource_ids - res_q = session.query(distinct(models.Resource.resource_id)).join( - models.Sample, - models.Sample.resource_id == models.Resource.internal_id) + has_timestamp = start_timestamp or end_timestamp + # NOTE: When sql_expire_samples_only is enabled, there will be some + # resources without any sample, in such case we should use inner + # join on sample table to avoid wrong result. + if cfg.CONF.sql_expire_samples_only or has_timestamp: + res_q = session.query(distinct(models.Resource.resource_id)).join( + models.Sample, + models.Sample.resource_id == models.Resource.internal_id) + else: + res_q = session.query(distinct(models.Resource.resource_id)) res_q = make_query_from_filter(session, res_q, s_filter, require_meter=False) |