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https://issues.apache.org/jira/browse/CASSANDRA-21118?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Caleb Rackliffe updated CASSANDRA-21118:
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Bug Category: Parent values: Degradation(12984)Level 1 values: Performance
Bug/Regression(12997)
Complexity: Normal
Component/s: Feature/SAI
Discovered By: Code Inspection
Severity: Normal
Status: Open (was: Triage Needed)
> SAI query on indexed static column reads full partition
> -------------------------------------------------------
>
> Key: CASSANDRA-21118
> URL: https://issues.apache.org/jira/browse/CASSANDRA-21118
> Project: Apache Cassandra
> Issue Type: Bug
> Components: Feature/SAI
> Reporter: Michael Marshall
> Assignee: Caleb Rackliffe
> Priority: Normal
>
> The `ResultRetriever` in SAI materializes `matches` eagerly instead of
> iteratively, and as a result, when a static primary key is used to create the
> partition iterator, we iterate the full partition, independent of the `limit`
> value. Here is a test that demonstrates the problem (it doesn't fail, so
> you'll need to add logging or attach a debugger).
> {code:java}
> @Test
> public void staticIndexOnlyMaterializesLimitRowsFromPartition() throws
> Throwable
> {
> createTable("CREATE TABLE %s (pk int, ck int, val1 int static, val2
> int, PRIMARY KEY(pk, ck))");
> disableCompaction(KEYSPACE);
> createIndex("CREATE INDEX ON %s(val1) USING 'sai'");
> execute("INSERT INTO %s(pk, ck, val1, val2) VALUES(?, ?, ?, ?)", 1,
> 1, 2, 1);
> for (int i = 2; i < 10000; i++)
> execute("INSERT INTO %s(pk, ck, val2) VALUES(?, ?, ?)",
> 1, i, i);
> beforeAndAfterFlush(() -> assertRows(execute("SELECT pk, ck, val1,
> val2 FROM %s WHERE val1 = 2 LIMIT 3"),
> row(1, 1, 2, 1), row(1, 2, 2,
> 2), row(1, 3, 2, 3)));
> }
> {code}
> The proper solution is to apply an iterator based filter so that rows are
> lazily filtered. It might be worth reviewing the git history to see if it was
> implemented that way initially.
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