[ https://issues.apache.org/jira/browse/CASSANDRA-8859?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14335511#comment-14335511 ]
Michael Mior commented on CASSANDRA-8859: ----------------------------------------- Thanks for clarifying! Is there a simple example of a scenario where the {{collectTimeOrderedData}} code path will be used? > CollationController not using collectTimeOrderedData > ---------------------------------------------------- > > Key: CASSANDRA-8859 > URL: https://issues.apache.org/jira/browse/CASSANDRA-8859 > Project: Cassandra > Issue Type: Bug > Components: Core > Reporter: Michael Mior > Priority: Minor > > I'd appreciate some help with a Cassandra 2.1.2 issue I'm experiencing. I'm > running a query which looks like this: > {code} > CREATE TABLE single_row_fetch (id uuid PRIMARY KEY, data text) > SELECT data FROM single_row_fetch WHERE id = ? > {code} > When writing test data into this table, I disabled compaction. I then wrote > data for performed a flush, and then overwrote the data, and so on. I varied > the number of times the data was overwritten and flushed. This has the effect > of controlling the number of SSTables. However, given that the table only has > one non-key row, only a single SSTable will ever have the most recent data > for this row. I confirmed that the expected number of SSTables were generated > and the timestamps of the are as expected. > However, when I run the query with tracing, I see that Cassandra still reads > from ALL of the SSTables via {{collectAllData}} in {{CollationController}}. > Given that this query only fetches a single column, I would expect this query > to take the {{collectTimeOrderedData}} code path and then only examine the > first SSTable after seeing that it contains the relevant data. > Any insights on why this is the case and it what situations I would get the > expected behaviour would be incredibly helpful! -- This message was sent by Atlassian JIRA (v6.3.4#6332)