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The following commit(s) were added to refs/heads/trunk by this push:
new f41b625e48 Expose Metric for Prepared Statement Cache Size (in bytes)
f41b625e48 is described below
commit f41b625e487b2f4d2fe319f6097b1b11e9f00f96
Author: Isaac Reath <[email protected]>
AuthorDate: Fri Feb 23 14:54:30 2024 -0500
Expose Metric for Prepared Statement Cache Size (in bytes)
Patch by Isaac Reath; Reviewed by Paulo Motta and guo Maxwell for
CASSANDRA-20864
Closes #4345
---
CHANGES.txt | 1 +
.../pages/managing/operating/metrics.adoc | 2 +
.../org/apache/cassandra/cql3/QueryProcessor.java | 11 +++++
.../org/apache/cassandra/metrics/CQLMetrics.java | 2 +
.../apache/cassandra/metrics/CQLMetricsTest.java | 51 ++++++++++++++++++----
5 files changed, 59 insertions(+), 8 deletions(-)
diff --git a/CHANGES.txt b/CHANGES.txt
index 08ae2c6162..f14cf1e6c1 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -1,4 +1,5 @@
5.1
+ * Expose Metric for Prepared Statement Cache Size (in bytes) (CASSANDRA-20864)
* Add support for BEGIN TRANSACTION to allow mutations that touch multiple
partitions (CASSANDRA-20857)
* AutoRepair: Safeguard Full repair against disk protection(CASSANDRA-20045)
* BEGIN TRANSACTION crashes if a mutation touches multiple rows
(CASSANDRA-20844)
diff --git a/doc/modules/cassandra/pages/managing/operating/metrics.adoc
b/doc/modules/cassandra/pages/managing/operating/metrics.adoc
index 6156682550..2dc6d4fd99 100644
--- a/doc/modules/cassandra/pages/managing/operating/metrics.adoc
+++ b/doc/modules/cassandra/pages/managing/operating/metrics.adoc
@@ -671,6 +671,8 @@ executed.
|PreparedStatementsRatio |Gauge<Double> |Percentage of statements that
are prepared vs unprepared.
+
+|PreparedStatementsCacheSize | Gauge<Long> | The size of the prepared
statements cache in bytes.
|===
[[dropped-metrics]]
diff --git a/src/java/org/apache/cassandra/cql3/QueryProcessor.java
b/src/java/org/apache/cassandra/cql3/QueryProcessor.java
index 7954a7bfc1..8f22bda5c8 100644
--- a/src/java/org/apache/cassandra/cql3/QueryProcessor.java
+++ b/src/java/org/apache/cassandra/cql3/QueryProcessor.java
@@ -42,6 +42,7 @@ import com.github.benmanes.caffeine.cache.Cache;
import com.github.benmanes.caffeine.cache.Caffeine;
import com.github.benmanes.caffeine.cache.RemovalCause;
import org.antlr.runtime.RecognitionException;
+
import org.apache.cassandra.concurrent.ImmediateExecutor;
import org.apache.cassandra.concurrent.ScheduledExecutors;
import org.apache.cassandra.config.DatabaseDescriptor;
@@ -178,6 +179,16 @@ public class QueryProcessor implements QueryHandler
return preparedStatements.asMap().size();
}
+ public static long preparedStatementsCacheMemoryUsedBytes()
+ {
+ long preparedStatementsCacheMemoryUsedBytes = 0;
+ for (Map.Entry<MD5Digest, Prepared> entry :
preparedStatements.asMap().entrySet())
+ {
+ preparedStatementsCacheMemoryUsedBytes +=
getSizeOfPreparedStatementForCache(entry.getKey(), entry.getValue());
+ }
+ return preparedStatementsCacheMemoryUsedBytes;
+ }
+
// Work around initialization dependency
private enum InternalStateInstance
{
diff --git a/src/java/org/apache/cassandra/metrics/CQLMetrics.java
b/src/java/org/apache/cassandra/metrics/CQLMetrics.java
index edf13dfb4e..ad6c571b78 100644
--- a/src/java/org/apache/cassandra/metrics/CQLMetrics.java
+++ b/src/java/org/apache/cassandra/metrics/CQLMetrics.java
@@ -37,6 +37,7 @@ public class CQLMetrics
public final Gauge<Integer> preparedStatementsCount;
public final Gauge<Double> preparedStatementsRatio;
+ public final Gauge<Long> preparedStatementsCacheSize;
public CQLMetrics()
{
@@ -64,5 +65,6 @@ public class CQLMetrics
return regularStatementsExecuted.getCount() +
preparedStatementsExecuted.getCount();
}
});
+ preparedStatementsCacheSize =
Metrics.register(factory.createMetricName("PreparedStatementsCacheSize"),
QueryProcessor::preparedStatementsCacheMemoryUsedBytes);
}
}
diff --git a/test/unit/org/apache/cassandra/metrics/CQLMetricsTest.java
b/test/unit/org/apache/cassandra/metrics/CQLMetricsTest.java
index 4c447a7012..a1681f169e 100644
--- a/test/unit/org/apache/cassandra/metrics/CQLMetricsTest.java
+++ b/test/unit/org/apache/cassandra/metrics/CQLMetricsTest.java
@@ -31,9 +31,12 @@ import com.datastax.driver.core.Session;
import com.datastax.driver.core.exceptions.InvalidQueryException;
import org.apache.cassandra.ServerTestUtils;
import org.apache.cassandra.config.DatabaseDescriptor;
+import org.apache.cassandra.cql3.QueryHandler;
import org.apache.cassandra.cql3.QueryProcessor;
import org.apache.cassandra.exceptions.ConfigurationException;
+import org.apache.cassandra.service.ClientState;
import org.apache.cassandra.service.EmbeddedCassandraService;
+import org.apache.cassandra.utils.MD5Digest;
import static org.apache.cassandra.cql3.CQLTester.assertRowsContains;
import static org.apache.cassandra.cql3.CQLTester.row;
@@ -95,18 +98,50 @@ public class CQLMetricsTest
}
@Test
- public void testPreparedStatementsCount()
+ public void testPreparedStatementsCountWithUse()
+ {
+ int n = QueryProcessor.metrics.preparedStatementsCount.getValue();
+ // Use local test session to avoid interference with other tests due
to CASSANDRA-17248
+ try (Session localSession = cluster.connect())
+ {
+ long useCountBefore =
QueryProcessor.metrics.useStatementsExecuted.getCount();
+ localSession.execute("use junit");
+ Assert.assertEquals(useCountBefore + 1,
QueryProcessor.metrics.useStatementsExecuted.getCount());
+ localSession.prepare("SELECT * FROM junit.metricstest WHERE id =
?");
+ assertEquals(n + 2, (int)
QueryProcessor.metrics.preparedStatementsCount.getValue());
+
+ assertRowsContains(cluster, session.execute("SELECT * FROM
system_metrics.cql_group"),
+
row("org.apache.cassandra.metrics.CQL.PreparedStatementsCount",
METRIC_SCOPE_UNDEFINED, "gauge",
+
String.valueOf(QueryProcessor.metrics.preparedStatementsCount.getValue())));
+ }
+ }
+
+ @Test
+ public void testPreparedStatementsCountWithoutUse()
{
int n = QueryProcessor.metrics.preparedStatementsCount.getValue();
long useCountBefore =
QueryProcessor.metrics.useStatementsExecuted.getCount();
- session.execute("use junit");
- Assert.assertEquals(useCountBefore + 1,
QueryProcessor.metrics.useStatementsExecuted.getCount());
- session.prepare("SELECT * FROM junit.metricstest WHERE id = ?");
- assertEquals(n+2, (int)
QueryProcessor.metrics.preparedStatementsCount.getValue());
+ session.prepare("SELECT * FROM junit.metricstest WHERE id = 101");
+ Assert.assertEquals(useCountBefore,
QueryProcessor.metrics.useStatementsExecuted.getCount());
+ assertEquals(n+1, (int)
QueryProcessor.metrics.preparedStatementsCount.getValue());
+ }
- assertRowsContains(cluster, session.execute("SELECT * FROM
system_metrics.cql_group"),
-
row("org.apache.cassandra.metrics.CQL.PreparedStatementsCount",
METRIC_SCOPE_UNDEFINED, "gauge",
-
String.valueOf(QueryProcessor.metrics.preparedStatementsCount.getValue())));
+ @Test
+ public void testPreparedStatementCacheMemoryUsed()
+ {
+ long n = QueryProcessor.metrics.preparedStatementsCacheSize.getValue();
+ String rawQueryString = "SELECT id, val FROM junit.metricstest WHERE
id = 100";
+ PreparedStatement s = session.prepare(rawQueryString);
+
+ // Compute the expected size of a prepared statement.
+ QueryHandler.Prepared expected =
QueryProcessor.parseAndPrepare(rawQueryString, ClientState.forInternalCalls(),
false);
+ MD5Digest hashValue = MD5Digest.compute(rawQueryString);
+ long expectedHashSize = hashValue.size();
+ long expectedStatementSize = expected.pstmntSize;
+ long expectedSize = expectedHashSize + expectedStatementSize;
+
+ long actualSize =
QueryProcessor.metrics.preparedStatementsCacheSize.getValue() - n;
+ assertEquals(expectedSize, actualSize);
}
@Test
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