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chore: use a cache for the statement parser (#2790)
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* chore: use a cache for the statement parser

Add a cache for the statement parser that is used in the Connection API.
This will reduce the number of times that a SQL string needs to be
parsed by the JDBC driver and PGAdapter.

* docs: fix/update comments

* chore: add 'mb' to cache size property name

* chore: use variable

* 🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

---------

Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>
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olavloite and gcf-owl-bot[bot] authored Jan 29, 2024
1 parent 655000a commit 340ba13
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Showing 3 changed files with 177 additions and 8 deletions.
111 changes: 103 additions & 8 deletions ...ud-spanner/src/main/java/com/google/cloud/spanner/connection/AbstractStatementParser.java
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Original file line number Diff line number Diff line change
Expand Up @@ -25,6 +25,10 @@
import com.google.cloud.spanner.connection.StatementResult.ClientSideStatementType;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Preconditions;
import com.google.common.cache.Cache;
import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheStats;
import com.google.common.cache.Weigher;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSet;
import com.google.spanner.v1.ExecuteSqlRequest.QueryOptions;
Expand Down Expand Up @@ -59,6 +63,13 @@ public abstract class AbstractStatementParser {
Dialect.POSTGRESQL,
PostgreSQLStatementParser.class);

@VisibleForTesting
static void resetParsers() {
synchronized (lock) {
INSTANCES.clear();
}
}

/**
* Get an instance of {@link AbstractStatementParser} for the specified dialect.
*
Expand Down Expand Up @@ -171,7 +182,7 @@ private static ParsedStatement ddl(Statement statement, String sqlWithoutComment
private static ParsedStatement query(
Statement statement, String sqlWithoutComments, QueryOptions defaultQueryOptions) {
return new ParsedStatement(
StatementType.QUERY, statement, sqlWithoutComments, defaultQueryOptions, false);
StatementType.QUERY, null, statement, sqlWithoutComments, defaultQueryOptions, false);
}

private static ParsedStatement update(
Expand All @@ -193,7 +204,7 @@ private ParsedStatement(
this.type = StatementType.CLIENT_SIDE;
this.clientSideStatement = clientSideStatement;
this.statement = statement;
this.sqlWithoutComments = sqlWithoutComments;
this.sqlWithoutComments = Preconditions.checkNotNull(sqlWithoutComments);
this.returningClause = false;
}

Expand All @@ -202,28 +213,48 @@ private ParsedStatement(
Statement statement,
String sqlWithoutComments,
boolean returningClause) {
this(type, statement, sqlWithoutComments, null, returningClause);
this(type, null, statement, sqlWithoutComments, null, returningClause);
}

private ParsedStatement(StatementType type, Statement statement, String sqlWithoutComments) {
this(type, statement, sqlWithoutComments, null, false);
this(type, null, statement, sqlWithoutComments, null, false);
}

private ParsedStatement(
StatementType type,
ClientSideStatementImpl clientSideStatement,
Statement statement,
String sqlWithoutComments,
QueryOptions defaultQueryOptions,
boolean returningClause) {
Preconditions.checkNotNull(type);
Preconditions.checkNotNull(statement);
this.type = type;
this.clientSideStatement = null;
this.statement = mergeQueryOptions(statement, defaultQueryOptions);
this.sqlWithoutComments = sqlWithoutComments;
this.clientSideStatement = clientSideStatement;
this.statement = statement == null ? null : mergeQueryOptions(statement, defaultQueryOptions);
this.sqlWithoutComments = Preconditions.checkNotNull(sqlWithoutComments);
this.returningClause = returningClause;
}

private ParsedStatement copy(Statement statement, QueryOptions defaultQueryOptions) {
return new ParsedStatement(
this.type,
this.clientSideStatement,
statement,
this.sqlWithoutComments,
defaultQueryOptions,
this.returningClause);
}

private ParsedStatement forCache() {
return new ParsedStatement(
this.type,
this.clientSideStatement,
null,
this.sqlWithoutComments,
null,
this.returningClause);
}

@Override
public int hashCode() {
return Objects.hash(
Expand Down Expand Up @@ -361,8 +392,58 @@ ClientSideStatement getClientSideStatement() {
static final Set<String> dmlStatements = ImmutableSet.of("INSERT", "UPDATE", "DELETE");
private final Set<ClientSideStatementImpl> statements;

/** The default maximum size of the statement cache in Mb. */
public static final int DEFAULT_MAX_STATEMENT_CACHE_SIZE_MB = 5;

private static int getMaxStatementCacheSize() {
String stringValue = System.getProperty("spanner.statement_cache_size_mb");
if (stringValue == null) {
return DEFAULT_MAX_STATEMENT_CACHE_SIZE_MB;
}
int value = 0;
try {
value = Integer.parseInt(stringValue);
} catch (NumberFormatException ignore) {
}
return Math.max(value, 0);
}

private static boolean isRecordStatementCacheStats() {
return "true"
.equalsIgnoreCase(System.getProperty("spanner.record_statement_cache_stats", "false"));
}

/**
* Cache for parsed statements. This prevents statements that are executed multiple times by the
* application to be parsed over and over again. The default maximum size is 5Mb.
*/
private final Cache<String, ParsedStatement> statementCache;

AbstractStatementParser(Set<ClientSideStatementImpl> statements) {
this.statements = Collections.unmodifiableSet(statements);
int maxCacheSize = getMaxStatementCacheSize();
if (maxCacheSize > 0) {
CacheBuilder<String, ParsedStatement> cacheBuilder =
CacheBuilder.newBuilder()
// Set the max size to (approx) 5MB (by default).
.maximumWeight(maxCacheSize * 1024L * 1024L)
// We do length*2 because Java uses 2 bytes for each char.
.weigher(
(Weigher<String, ParsedStatement>)
(key, value) -> 2 * key.length() + 2 * value.sqlWithoutComments.length())
.concurrencyLevel(Runtime.getRuntime().availableProcessors());
if (isRecordStatementCacheStats()) {
cacheBuilder.recordStats();
}
this.statementCache = cacheBuilder.build();
} else {
this.statementCache = null;
}
}

@VisibleForTesting
CacheStats getStatementCacheStats() {
return statementCache == null ? null : statementCache.stats();
}

@VisibleForTesting
Expand All @@ -383,6 +464,20 @@ public ParsedStatement parse(Statement statement) {
}

ParsedStatement parse(Statement statement, QueryOptions defaultQueryOptions) {
if (statementCache == null) {
return internalParse(statement, defaultQueryOptions);
}

ParsedStatement parsedStatement = statementCache.getIfPresent(statement.getSql());
if (parsedStatement == null) {
parsedStatement = internalParse(statement, null);
statementCache.put(statement.getSql(), parsedStatement.forCache());
return parsedStatement;
}
return parsedStatement.copy(statement, defaultQueryOptions);
}

private ParsedStatement internalParse(Statement statement, QueryOptions defaultQueryOptions) {
String sql = removeCommentsAndTrim(statement.getSql());
ClientSideStatementImpl client = parseClientSideStatement(sql);
if (client != null) {
Expand Down
1 change: 1 addition & 0 deletions google-cloud-spanner/src/test/java/com/google/cloud/spanner/SessionPoolStressTest.java
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Original file line number Diff line number Diff line change
Expand Up @@ -294,6 +294,7 @@ public void stressTest() throws Exception {
() -> {
while (!stopMaintenance.get()) {
runMaintenanceLoop(clock, pool, 1);
Uninterruptibles.sleepUninterruptibly(1L, TimeUnit.MILLISECONDS);
}
})
.start();
Expand Down
73 changes: 73 additions & 0 deletions ...-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/StatementParserTest.java
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Original file line number Diff line number Diff line change
Expand Up @@ -22,6 +22,7 @@
import static org.hamcrest.MatcherAssert.assertThat;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertNotSame;
import static org.junit.Assert.assertTrue;
import static org.junit.Assert.fail;
import static org.junit.Assume.assumeTrue;
Expand All @@ -34,6 +35,7 @@
import com.google.cloud.spanner.connection.AbstractStatementParser.StatementType;
import com.google.cloud.spanner.connection.ClientSideStatementImpl.CompileException;
import com.google.cloud.spanner.connection.StatementResult.ClientSideStatementType;
import com.google.common.cache.CacheStats;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSet;
import com.google.common.truth.Truth;
Expand All @@ -43,9 +45,12 @@
import java.util.List;
import java.util.Scanner;
import java.util.Set;
import java.util.UUID;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.junit.AfterClass;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.Parameterized;
Expand Down Expand Up @@ -81,6 +86,17 @@ public static Object[] data() {

private AbstractStatementParser parser;

@BeforeClass
public static void enableStatementCacheStats() {
AbstractStatementParser.resetParsers();
System.setProperty("spanner.record_statement_cache_stats", "true");
}

@AfterClass
public static void disableStatementCacheStats() {
System.clearProperty("spanner.record_statement_cache_stats");
}

@Before
public void setupParser() {
parser = AbstractStatementParser.getInstance(dialect);
Expand Down Expand Up @@ -1641,6 +1657,63 @@ public void testSkipMultiLineComment() {
skipMultiLineComment("/* foo /* inner comment */ not in inner comment */ bar", 0));
}

@Test
public void testStatementCache_NonParameterizedStatement() {
CacheStats statsBefore = parser.getStatementCacheStats();

String sql = "select foo from bar where id=" + UUID.randomUUID();
ParsedStatement parsedStatement1 = parser.parse(Statement.of(sql));
assertEquals(StatementType.QUERY, parsedStatement1.getType());

ParsedStatement parsedStatement2 = parser.parse(Statement.of(sql));
assertEquals(StatementType.QUERY, parsedStatement2.getType());

// Even though the parsed statements are cached, the returned instances are not the same.
// This makes sure that statements with the same SQL string and different parameter values
// can use the cache.
assertNotSame(parsedStatement1, parsedStatement2);

CacheStats statsAfter = parser.getStatementCacheStats();
CacheStats stats = statsAfter.minus(statsBefore);

// The first query had a cache miss. The second a cache hit.
assertEquals(1, stats.missCount());
assertEquals(1, stats.hitCount());
}

@Test
public void testStatementCache_ParameterizedStatement() {
CacheStats statsBefore = parser.getStatementCacheStats();

String sql =
"select "
+ UUID.randomUUID()
+ " from bar where id="
+ (dialect == Dialect.POSTGRESQL ? "$1" : "@p1");
Statement statement1 = Statement.newBuilder(sql).bind("p1").to(1L).build();
Statement statement2 = Statement.newBuilder(sql).bind("p1").to(2L).build();

ParsedStatement parsedStatement1 = parser.parse(statement1);
assertEquals(StatementType.QUERY, parsedStatement1.getType());
assertEquals(parsedStatement1.getStatement(), statement1);

ParsedStatement parsedStatement2 = parser.parse(statement2);
assertEquals(StatementType.QUERY, parsedStatement2.getType());
assertEquals(parsedStatement2.getStatement(), statement2);

// Even though the parsed statements are cached, the returned instances are not the same.
// This makes sure that statements with the same SQL string and different parameter values
// can use the cache.
assertNotSame(parsedStatement1, parsedStatement2);

CacheStats statsAfter = parser.getStatementCacheStats();
CacheStats stats = statsAfter.minus(statsBefore);

// The first query had a cache miss. The second a cache hit.
assertEquals(1, stats.missCount());
assertEquals(1, stats.hitCount());
}

private void assertUnclosedLiteral(String sql) {
try {
parser.convertPositionalParametersToNamedParameters('?', sql);
Expand Down

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