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Merged
rahul2393 merged 7 commits into from
Aug 20, 2026
Merged

perf(spanner-jdbc): cache JDBC metadata query strings #14041

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ad97128
perf(spanner-jdbc): cache JDBC metadata query strings
olavloite Aug 11, 2026
62447b1
Merge branch 'main' into cache-metadata-queries
olavloite Aug 13, 2026
14bac61
chore(spanner-jdbc): address review comments
olavloite Aug 13, 2026
f6db9ea
Merge branch 'main' into cache-metadata-queries
rahul2393 Aug 18, 2026
40d5d98
test(spanner-jdbc): unflake sample tests
olavloite Aug 19, 2026
13f5a2a
Merge branch 'main' into cache-metadata-queries
olavloite Aug 20, 2026
37ac2c5
chore(spanner-jdbc): address review comments
olavloite Aug 20, 2026
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42 changes: 36 additions & 6 deletions ...atis/googlesql/src/test/java/com/google/cloud/spanner/sample/ApplicationEmulatorTest.java
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Expand Up @@ -18,25 +18,55 @@

import static org.junit.Assume.assumeTrue;

import com.google.cloud.spanner.connection.SpannerPool;
import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;
import org.springframework.boot.SpringApplication;
import org.testcontainers.DockerClientFactory;
import org.testcontainers.containers.GenericContainer;
import org.testcontainers.containers.wait.strategy.Wait;
import org.testcontainers.utility.DockerImageName;

@RunWith(JUnit4.class)
public class ApplicationEmulatorTest {
private static GenericContainer<?> emulator;

@BeforeClass
public static void checkDocker() {
assumeTrue(
"Docker is required for this test", DockerClientFactory.instance().isDockerAvailable());
public static void startEmulator() {
assumeTrue(DockerClientFactory.instance().isDockerAvailable());

emulator =
new GenericContainer<>(
DockerImageName.parse("gcr.io/cloud-spanner-emulator/emulator:latest"))
.withExposedPorts(9010)
.waitingFor(Wait.forLogMessage(".*gRPC server listening at.*\\n", 1));
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emulator.start();
}

@AfterClass
public static void cleanup() {
SpannerPool.closeSpannerPool();
if (emulator != null) {
emulator.stop();
}
System.clearProperty("open_telemetry.enabled");
System.clearProperty("open_telemetry.project");
System.clearProperty("spanner.emulator");
System.clearProperty("spanner.auto_start_emulator");
System.clearProperty("spanner.endpoint");
}
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@Test
public void testRunApplicationOnEmulator() {
public void testRunApplication() {
System.setProperty("open_telemetry.enabled", "false");
System.setProperty("open_telemetry.project", "test-project");
System.setProperty("spanner.emulator", "true");
System.setProperty("spanner.auto_start_emulator", "true");
Application.main(new String[] {});
System.setProperty("spanner.auto_start_emulator", "false");
System.setProperty(
"spanner.endpoint", String.format("//localhost:%d", emulator.getMappedPort(9010)));
SpringApplication.run(Application.class).close();
}
}
43 changes: 41 additions & 2 deletions ...tis/postgresql/src/test/java/com/google/cloud/spanner/sample/ApplicationEmulatorTest.java
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Expand Up @@ -16,16 +16,55 @@

package com.google.cloud.spanner.sample;

import static org.junit.Assume.assumeTrue;

import com.google.cloud.spanner.connection.SpannerPool;
import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;
import org.springframework.boot.SpringApplication;
import org.testcontainers.DockerClientFactory;
import org.testcontainers.containers.GenericContainer;
import org.testcontainers.containers.wait.strategy.Wait;
import org.testcontainers.utility.DockerImageName;

@RunWith(JUnit4.class)
public class ApplicationEmulatorTest {
private static GenericContainer<?> emulator;

@BeforeClass
public static void startEmulator() {
assumeTrue(DockerClientFactory.instance().isDockerAvailable());

emulator =
new GenericContainer<>(
DockerImageName.parse("gcr.io/cloud-spanner-emulator/emulator:latest"))
.withExposedPorts(9010)
.waitingFor(Wait.forLogMessage(".*gRPC server listening at.*\\n", 1));
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emulator.start();
}

@AfterClass
public static void cleanup() {
SpannerPool.closeSpannerPool();
if (emulator != null) {
emulator.stop();
}
System.clearProperty("open_telemetry.enabled");
System.clearProperty("open_telemetry.project");
System.clearProperty("spanner.emulator");
System.clearProperty("spanner.endpoint");
}
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@Test
public void testRunApplicationOnEmulator() {
public void testRunApplication() {
System.setProperty("open_telemetry.enabled", "false");
System.setProperty("open_telemetry.project", "test-project");
System.setProperty("spanner.emulator", "true");
Application.main(new String[] {});
System.setProperty(
"spanner.endpoint", String.format("//localhost:%d", emulator.getMappedPort(9010)));
SpringApplication.run(Application.class).close();
}
}
42 changes: 30 additions & 12 deletions java-spanner-jdbc/src/main/java/com/google/cloud/spanner/jdbc/JdbcDatabaseMetaData.java
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Expand Up @@ -20,16 +20,20 @@
import com.google.auth.ServiceAccountSigner;
import com.google.auth.oauth2.UserCredentials;
import com.google.cloud.spanner.Dialect;
import com.google.cloud.spanner.ErrorCode;
import com.google.cloud.spanner.ResultSets;
import com.google.cloud.spanner.SpannerException;
import com.google.cloud.spanner.SpannerExceptionFactory;
import com.google.cloud.spanner.Struct;
import com.google.cloud.spanner.Type;
import com.google.cloud.spanner.Type.StructField;
import com.google.cloud.spanner.connection.Connection.InternalMetadataQuery;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.collect.ImmutableSet;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.nio.charset.StandardCharsets;
import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.ResultSet;
Expand All @@ -40,6 +44,8 @@
import java.util.Collections;
import java.util.Properties;
import java.util.Scanner;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;

/** {@link DatabaseMetaData} implementation for Cloud Spanner */
class JdbcDatabaseMetaData extends AbstractJdbcWrapper implements DatabaseMetaData {
Expand All @@ -50,24 +56,36 @@ class JdbcDatabaseMetaData extends AbstractJdbcWrapper implements DatabaseMetaDa
private static final String PRODUCT_NAME = "Google Cloud Spanner";
private static final String POSTGRESQL_PRODUCT_NAME = PRODUCT_NAME + " PostgreSQL";

private static final ConcurrentMap<String, String> SQL_CACHE = new ConcurrentHashMap<>();

@rahul2393 rahul2393 Aug 20, 2026

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Cache is unbounded but negligible risk since metadata are bounded.


@VisibleForTesting
static String readSqlFromFile(String filename, Dialect dialect) {
InputStream in;
switch (dialect) {
case POSTGRESQL:
in = JdbcDatabaseMetaData.class.getResourceAsStream("postgresql/" + filename);
break;
case GOOGLE_STANDARD_SQL:
default:
in = JdbcDatabaseMetaData.class.getResourceAsStream(filename);
static String readSqlFromFile(String filename, Dialect dialect) throws SQLException {
try {
return SQL_CACHE.computeIfAbsent(
filename + "/" + dialect, (key) -> loadSqlFromFile(filename, dialect));
} catch (SpannerException e) {
throw JdbcSqlExceptionFactory.of(e);
}
}
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private static String loadSqlFromFile(String filename, Dialect dialect) {
String resourcePath = dialect == Dialect.POSTGRESQL ? "postgresql/" + filename : filename;
InputStream in = JdbcDatabaseMetaData.class.getResourceAsStream(resourcePath);
if (in == null) {
throw SpannerExceptionFactory.newSpannerException(
ErrorCode.NOT_FOUND, "Resource not found: " + resourcePath);
}
BufferedReader reader = new BufferedReader(new InputStreamReader(in));
StringBuilder builder = new StringBuilder();
try (Scanner scanner = new Scanner(reader)) {
try (InputStream input = in;
InputStreamReader reader = new InputStreamReader(input, StandardCharsets.UTF_8);
Scanner scanner = new Scanner(reader)) {
while (scanner.hasNextLine()) {
String line = scanner.nextLine();
builder.append(line).append("\n");
}
} catch (IOException e) {
throw SpannerExceptionFactory.newSpannerException(

@rahul2393 rahul2393 Aug 20, 2026

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nit: earlier there was a chance of NPE, and now better

Just wanted to fyi since the PR title did not mention it

ErrorCode.INTERNAL, "Could not read SQL file " + resourcePath, e);
}
return builder.toString();
}
Expand Down
19 changes: 19 additions & 0 deletions java-spanner-jdbc/src/test/java/com/google/cloud/spanner/jdbc/JdbcDatabaseMetaDataTest.java
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Expand Up @@ -19,6 +19,8 @@
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertNotNull;
import static org.junit.Assert.assertSame;
import static org.junit.Assert.assertThrows;
import static org.junit.Assert.assertTrue;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.when;
Expand Down Expand Up @@ -574,4 +576,21 @@ public void testGetUserName() throws SQLException, IOException {
DatabaseMetaData meta = new JdbcDatabaseMetaData(connection);
assertEquals("test@test-project.iam.gserviceaccount.com", meta.getUserName());
}

@Test
public void testReadSqlFromFileCaching() throws SQLException {
String sql1 = JdbcDatabaseMetaData.readSqlFromFile("DatabaseMetaData_GetTables.sql", dialect);
String sql2 = JdbcDatabaseMetaData.readSqlFromFile("DatabaseMetaData_GetTables.sql", dialect);
assertNotNull(sql1);
assertSame(sql1, sql2);
}

@Test
public void testReadSqlFromFileNotFound() {
SQLException exception =
assertThrows(
SQLException.class,
() -> JdbcDatabaseMetaData.readSqlFromFile("NonExistent.sql", dialect));
assertTrue(exception.getMessage().contains("Resource not found"));
}
}
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