Michael Mior created CASSANDRA-8859:
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Summary: 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!
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