Andres de la Peña created CASSANDRA-17187:
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Summary: Guardrail for SELECT IN terms and their cartesian product
Key: CASSANDRA-17187
URL: https://issues.apache.org/jira/browse/CASSANDRA-17187
Project: Cassandra
Issue Type: New Feature
Components: Feature/Guardrails
Reporter: Andres de la Peña
Add a guardrail to limit the number restrictions generated by the cartesian
product of the {{IN}} restrictions of a {{SELECT}} query, for example:
{code}
# Guardrail to warn or abort when IN query creates a cartesian product with a
# size exceeding threshold, eg. "a in (1,2,...10) and b in (1,2...10)" results
in
# cartesian product of 100.
# The two thresholds default to -1 to disable.
in_select_cartesian_product:
warn_threshold: -1
abort_threshold: -1
{code}
As an example of why this guardrails is proposed, these queries bring a C*
instance to its knees even before the query starts executing:
{code}
@Test
public void testPartitionKeyTerms() throws Throwable
{
createTable("CREATE TABLE %s (pk1 int, pk2 int, pk3 int, pk4 int, pk5 int,
pk6 int, pk7 int, pk8 int, pk9 int, " +
"PRIMARY KEY((pk1, pk2, pk3, pk4, pk5, pk6, pk7, pk8, pk9)))");
execute("SELECT * FROM %s WHERE pk1 in (1, 2, 3, 4, 5, 6, 7, 8, 9, 10) " +
"AND pk2 in (1, 2, 3, 4, 5, 6, 7, 8, 9, 10) " +
"AND pk3 in (1, 2, 3, 4, 5, 6, 7, 8, 9, 10) " +
"AND pk4 in (1, 2, 3, 4, 5, 6, 7, 8, 9, 10) " +
"AND pk5 in (1, 2, 3, 4, 5, 6, 7, 8, 9, 10) " +
"AND pk6 in (1, 2, 3, 4, 5, 6, 7, 8, 9, 10) " +
"AND pk7 in (1, 2, 3, 4, 5, 6, 7, 8, 9, 10) " +
"AND pk8 in (1, 2, 3, 4, 5, 6, 7, 8, 9, 10) " +
"AND pk9 in (1, 2, 3, 4, 5, 6, 7, 8, 9, 10);");
}
@Test
public void testClusteringKeyTerms() throws Throwable
{
createTable("CREATE TABLE %s (pk int ,ck1 int, ck2 int, ck3 int, ck4 int,
ck5 int, ck6 int, ck7 int, ck8 int, ck9 int, " +
"PRIMARY KEY(pk, ck1, ck2, ck3, ck4, ck5, ck6, ck7, ck8, ck9))");
execute("SELECT * FROM %s WHERE pk = 1 " +
"AND ck1 in (1, 2, 3, 4, 5, 6, 7, 8, 9, 10) " +
"AND ck2 in (1, 2, 3, 4, 5, 6, 7, 8, 9, 10) " +
"AND ck3 in (1, 2, 3, 4, 5, 6, 7, 8, 9, 10) " +
"AND ck4 in (1, 2, 3, 4, 5, 6, 7, 8, 9, 10) " +
"AND ck5 in (1, 2, 3, 4, 5, 6, 7, 8, 9, 10) " +
"AND ck6 in (1, 2, 3, 4, 5, 6, 7, 8, 9, 10) " +
"AND ck7 in (1, 2, 3, 4, 5, 6, 7, 8, 9, 10) " +
"AND ck8 in (1, 2, 3, 4, 5, 6, 7, 8, 9, 10) " +
"AND ck9 in (1, 2, 3, 4, 5, 6, 7, 8, 9, 10);");
}
{code}
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