[ https://issues.apache.org/jira/browse/CASSANDRA-12768?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Sylvain Lebresne resolved CASSANDRA-12768. ------------------------------------------ Resolution: Fixed Merged to the misnamed branch. > CQL often queries static columns unnecessarily > ---------------------------------------------- > > Key: CASSANDRA-12768 > URL: https://issues.apache.org/jira/browse/CASSANDRA-12768 > Project: Cassandra > Issue Type: Bug > Reporter: Sylvain Lebresne > Assignee: Sylvain Lebresne > Fix For: 3.0.11, 3.10 > > > While looking at CASSANDRA-12694 (which isn't directly related, but some of > the results in this ticket are explained by this), I realized that CQL was > always querying static columns even in cases where this is unnecessary. > More precisely, for reasons long described elsewhere, we have to query all > the columns for a row (we have optimizations, see CASSANDRA-10657, but they > don't change that general fact) to be able to distinguish between the case > where a row doesn't exist from when it exists but has no values for the > columns selected by the query. *However*, this really only extend to > "regular" columns (static columns play no role in deciding whether a > particular row exists or not) but the implementation in 3.x, which is in > {{ColumnFilter}}, still always query all static columns. > We shouldn't do that and it's arguably a performance regression from 2.x. > Which is why I'm tentatively marking this a bug and for the 3.0 line. It's a > tiny bit scary for 3.0 though so really more asking for other opinions and > I'd be happy to stick to 3.x. -- This message was sent by Atlassian JIRA (v6.3.4#6332)