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本文主要研究一下tomcat jdbc pool的默认参数及poolSweeper
tomcat jdbc pool 参数默认值
- initialSize = 10(
默认值) - maxActive=100(
默认值) - maxIdle=100(
默认值) - minIdle=10(
默认值) - maxWait=30000(
默认值) - validationQueryTimeout=-1(
默认值) - testOnBorrow=false(
默认值) - testOnReturn=false(
默认值) - testWhileIdel=false(
默认值) - timeBetweenEvictionRunsMillis=5000(
默认值) - minEvictableIdleTimeMillis=60000(
默认值) - accessToUnderlyingConnectionAllowed=true(
默认值) - removeAbandoned=false(
默认值) - removeAbandonedTimeout=60(
默认值) - logAbandoned=false(
默认值) - validationInterval=3000(
默认值) - testOnConnect=false(
默认值) - fairQueue=true(
默认值) - abandonWhenPercentageFull=0(
默认值) - maxAge=0(
默认值) - suspectTimeout=0(
默认值) - alternateUsernameAllowed=false(
默认值) - commitOnReturn=false(
默认值) - rollbackOnReturn=false(
默认值) - useDisposableConnectionFacade=true(
默认值) - logValidationErrors=false(
默认值) - propageInterruptState=false(
默认值) - ignoreExceptionOnPreLoad=false(
默认值)
判断是否开启poolSweeper
tomcat-jdbc-8.5.11-sources.jar!/org/apache/tomcat/jdbc/pool/PoolProperties.java
@Override
public boolean isPoolSweeperEnabled() {
boolean timer = getTimeBetweenEvictionRunsMillis()>0;
boolean result = timer && (isRemoveAbandoned() && getRemoveAbandonedTimeout()>0);
result = result || (timer && getSuspectTimeout()>0);
result = result || (timer && isTestWhileIdle() && getValidationQuery()!=null);
result = result || (timer && getMinEvictableIdleTimeMillis()>0);
return result;
}如果timeBetweenEvictionRunsMillis不大于0，则肯定是关闭的，默认值为5000；即默认为true
之后是如下几个条件满足任意一个则开启
| 判断条件 | 默认值 | 结果 |
|---|---|---|
| getTimeBetweenEvictionRunsMillis()>0 | 默认为5000 | true |
| isRemoveAbandoned() && getRemoveAbandonedTimeout()>0 | 默认removeAbandoned为false，removeAbandonedTimeout为60 | false |
| getSuspectTimeout()>0 | 默认为0 | false |
| isTestWhileIdle() && getValidationQuery()!=null | 默认testWhileIdle为false,常见的mysql,pg,oracle的validationQuery不为空 | false |
| getMinEvictableIdleTimeMillis()>0 | 默认值为60000 | true |
默认为true,即会开启poolSweeper
DataSourceConfiguration
spring-boot-autoconfigure-1.4.5.RELEASE-sources.jar!/org/springframework/boot/autoconfigure/jdbc/DataSourceConfiguration.java
@ConditionalOnClass(org.apache.tomcat.jdbc.pool.DataSource.class)
@ConditionalOnProperty(name = "spring.datasource.type", havingValue = "org.apache.tomcat.jdbc.pool.DataSource", matchIfMissing = true)
static class Tomcat extends DataSourceConfiguration {
@Bean
@ConfigurationProperties("spring.datasource.tomcat")
public org.apache.tomcat.jdbc.pool.DataSource dataSource(
DataSourceProperties properties) {
org.apache.tomcat.jdbc.pool.DataSource dataSource = createDataSource(
properties, org.apache.tomcat.jdbc.pool.DataSource.class);
DatabaseDriver databaseDriver = DatabaseDriver
.fromJdbcUrl(properties.determineUrl());
String validationQuery = databaseDriver.getValidationQuery();
if (validationQuery != null) {
dataSource.setTestOnBorrow(true);
dataSource.setValidationQuery(validationQuery);
}
return dataSource;
}
}这里默认会根据连接url判断是哪类数据库,然后默认的常见数据库都有对应的validationQuery如果有validationQuery,则testOnBorrow会被设置为true
注意,如果使用通用的spring.datasource直接来配置,通用的driver-class-name,url,username和password会被认,validationQuery根据url来自动判断,如果能识别出,则testOnBorrow也会被设置为true,其他的连接池的参数,就需要根据具体实现来具体指定,比如spring.datasource.tomcat.initial-size,否则不生效
validationQuery
- DatabaseDriver
spring-boot-1.4.5.RELEASE-sources.jar!/org/springframework/boot/jdbc/DatabaseDriver.java
/**
* Apache Derby.
*/
DERBY("Apache Derby", "org.apache.derby.jdbc.EmbeddedDriver", null,
"SELECT 1 FROM SYSIBM.SYSDUMMY1"),
/**
* H2.
*/
H2("H2", "org.h2.Driver", "org.h2.jdbcx.JdbcDataSource", "SELECT 1"),
/**
* HyperSQL DataBase.
*/
HSQLDB("HSQL Database Engine", "org.hsqldb.jdbc.JDBCDriver",
"org.hsqldb.jdbc.pool.JDBCXADataSource",
"SELECT COUNT(*) FROM INFORMATION_SCHEMA.SYSTEM_USERS"),
/**
* SQL Lite.
*/
SQLITE("SQLite", "org.sqlite.JDBC"),
/**
* MySQL.
*/
MYSQL("MySQL", "com.mysql.jdbc.Driver",
"com.mysql.jdbc.jdbc2.optional.MysqlXADataSource", "SELECT 1"),
/**
* Maria DB.
*/
MARIADB("MySQL", "org.mariadb.jdbc.Driver", "org.mariadb.jdbc.MariaDbDataSource",
"SELECT 1"),
/**
* Oracle.
*/
ORACLE("Oracle", "oracle.jdbc.OracleDriver",
"oracle.jdbc.xa.client.OracleXADataSource", "SELECT 'Hello' from DUAL"),
/**
* Postgres.
*/
POSTGRESQL("PostgreSQL", "org.postgresql.Driver", "org.postgresql.xa.PGXADataSource",
"SELECT 1"),
关于poolCleaner
tomcat-jdbc-8.5.11-sources.jar!/org/apache/tomcat/jdbc/pool/ConnectionPool.java
/**
* Instantiate a connection pool. This will create connections if initialSize is larger than 0.
* The {@link PoolProperties} should not be reused for another connection pool.
* @param prop PoolProperties - all the properties for this connection pool
* @throws SQLException Pool initialization error
*/
public ConnectionPool(PoolConfiguration prop) throws SQLException {
//setup quick access variables and pools
init(prop);
}
public void initializePoolCleaner(PoolConfiguration properties) {
//if the evictor thread is supposed to run, start it now
if (properties.isPoolSweeperEnabled()) {
poolCleaner = new PoolCleaner(this, properties.getTimeBetweenEvictionRunsMillis());
poolCleaner.start();
} //end if
}ConnectionPool构造器初始化会调用initializePoolCleaner,判断是否开启poolCleaner,默认配置为true,即会开启poolCleaner
poolCleaner
protected static class PoolCleaner extends TimerTask {
protected WeakReference<ConnectionPool> pool;
protected long sleepTime;
PoolCleaner(ConnectionPool pool, long sleepTime) {
this.pool = new WeakReference<>(pool);
this.sleepTime = sleepTime;
if (sleepTime <= 0) {
log.warn("Database connection pool evicter thread interval is set to 0, defaulting to 30 seconds");
this.sleepTime = 1000 * 30;
} else if (sleepTime < 1000) {
log.warn("Database connection pool evicter thread interval is set to lower than 1 second.");
}
}
@Override
public void run() {
ConnectionPool pool = this.pool.get();
if (pool == null) {
stopRunning();
} else if (!pool.isClosed()) {
try {
if (pool.getPoolProperties().isRemoveAbandoned()
|| pool.getPoolProperties().getSuspectTimeout() > 0)
pool.checkAbandoned();
if (pool.getPoolProperties().getMinIdle() < pool.idle
.size())
pool.checkIdle();
if (pool.getPoolProperties().isTestWhileIdle())
pool.testAllIdle();
} catch (Exception x) {
log.error("", x);
}
}
}
public void start() {
registerCleaner(this);
}
public void stopRunning() {
unregisterCleaner(this);
}
}这个timer主要的任务如下
| 任务 | 执行条件 | 默认值 | 结果 |
|---|---|---|---|
| checkAbandoned | removeAbandoned为true或suspectTimeout大于0 | removeAbandoned为false,suspectTimeout为0 | false |
| checkIdle | pool.idel.size() > minIdle | 默认minIdle为10 | -- |
| testAllIdle | testWhileIdle为true | 默认为false | false |
由于这些任务是依次往下执行的,默认参数配置可以执行的是checkIdle()
只要removeAbandoned=true或者suspectTimeout大于0,就会执行checkAbandoned()
只要testWhileIdle为true,就会执行testAllIdle()
checkAbandoned
/**
* Iterates through all the busy connections and checks for connections that have timed out
*/
public void checkAbandoned() {
try {
if (busy.size()==0) return;
Iterator<PooledConnection> locked = busy.iterator();
int sto = getPoolProperties().getSuspectTimeout();
while (locked.hasNext()) {
PooledConnection con = locked.next();
boolean setToNull = false;
try {
con.lock();
//the con has been returned to the pool or released
//ignore it
if (idle.contains(con) || con.isReleased())
continue;
long time = con.getTimestamp();
long now = System.currentTimeMillis();
if (shouldAbandon() && (now - time) > con.getAbandonTimeout()) {
busy.remove(con);
abandon(con);
setToNull = true;
} else if (sto > 0 && (now - time) > (sto * 1000L)) {
suspect(con);
} else {
//do nothing
} //end if
} finally {
con.unlock();
if (setToNull)
con = null;
}
} //while
} catch (ConcurrentModificationException e) {
log.debug("checkAbandoned failed." ,e);
} catch (Exception e) {
log.warn("checkAbandoned failed, it will be retried.",e);
}
}suspectTimeout大于0,removeAbandoned=true两个条件一个成立就会执行checkAbandoned()
如果removeAbandoned为false,则只会进行suspect判断
如果开启removeAbandoned,那么在连接超过abandonTimeout时执行abandon,否则进入suspect判断
abandon会释放连接,即disconnect/close连接
abandon实例
连接池配置
spring:
datasource:
driver-class-name: org.postgresql.Driver
url: jdbc:postgresql://localhost:5432/postgres?connectTimeout=60&socketTimeout=60
username: postgres
password: postgres
jmx-enabled: true
tomcat:
initial-size: 1
max-active: 5
## when pool sweeper is enabled, extra idle connection will be closed
max-idle: 5
## when idle connection > min-idle, poolSweeper will start to close
min-idle: 1
# PoolSweeper run interval abandon及suspect检测的执行间隔
time-between-eviction-runs-millis: 30000
remove-abandoned: true
# how long a connection should return,if not return regard as leak connection
remove-abandoned-timeout: 10
# how long a connection should return, or regard as probably leak connection
suspect-timeout: 10
log-abandoned: true
abandon-when-percentage-full: 0 ## (used/max-active*100f)>=perc -->shouldAbandon, if set 0 always abandon
# idle connection idle time before close
min-evictable-idle-time-millis: 60000
validation-query: select 1
validation-interval: 30000实例代码
@Test
public void testConnAbandon() throws SQLException {
Connection connection = dataSource.getConnection();
connection.setAutoCommit(false); //NOTE pg 为了设置fetchSize,必须设置为false
String sql = "select * from demo_table";
PreparedStatement pstmt;
try {
pstmt = (PreparedStatement)connection.prepareStatement(sql);
pstmt.setFetchSize(10);
ResultSet rs = pstmt.executeQuery(); //NOTE 设置Statement执行完成的超时时间,前提是socket的timeout比这个大
//NOTE 这里返回了就代表statement执行完成,pg会顺带返回fetchSize大小的第一批数据,mysql不会返回第一批数据
int col = rs.getMetaData().getColumnCount();
System.out.println("============================");
while (rs.next()) { //NOTE 这个的timeout由socket的超时时间设置,oracle.jdbc.ReadTimeout=60000
for (int i = 1; i <= col; i++) {
System.out.print(rs.getObject(i));
}
System.out.println("");
TimeUnit.SECONDS.sleep(1); //NOTE 这里模拟连接被abandon
}
System.out.println("============================");
} catch (Exception e) {
e.printStackTrace();
} finally {
//close resources
}
}报错
2018-01-27 11:48:59.891 WARN 1004 --- [:1517024909680]] o.a.tomcat.jdbc.pool.ConnectionPool : Connection has been abandoned PooledConnection[org.postgresql.jdbc.PgConnection@6c6bdce1]:java.lang.Exception
at org.apache.tomcat.jdbc.pool.ConnectionPool.getThreadDump(ConnectionPool.java:1102)
at org.apache.tomcat.jdbc.pool.ConnectionPool.borrowConnection(ConnectionPool.java:807)
at org.apache.tomcat.jdbc.pool.ConnectionPool.borrowConnection(ConnectionPool.java:651)
at org.apache.tomcat.jdbc.pool.ConnectionPool.getConnection(ConnectionPool.java:198)
at org.apache.tomcat.jdbc.pool.DataSourceProxy.getConnection(DataSourceProxy.java:132)
at com.demo.JpaDemoApplicationTests.testConnAbandon(JpaDemoApplicationTests.java:59)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:75)
at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:86)
at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:84)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:252)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:94)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:191)
at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:69)
at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:234)
at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:74)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:144)
org.postgresql.util.PSQLException: An I/O error occurred while sending to the backend.
at org.postgresql.core.v3.QueryExecutorImpl.fetch(QueryExecutorImpl.java:2389)
at org.postgresql.jdbc.PgResultSet.next(PgResultSet.java:1841)
at com.demo.JpaDemoApplicationTests.testConnAbandon(JpaDemoApplicationTests.java:70)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:75)
at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:86)
at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:84)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:252)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:94)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:191)
at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:69)
at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:234)
at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:74)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:144)
Caused by: java.io.IOException: Stream closed
at sun.nio.cs.StreamEncoder.ensureOpen(StreamEncoder.java:45)
at sun.nio.cs.StreamEncoder.flush(StreamEncoder.java:140)
at java.io.OutputStreamWriter.flush(OutputStreamWriter.java:229)
at org.postgresql.core.PGStream.flush(PGStream.java:549)
at org.postgresql.core.v3.QueryExecutorImpl.sendSync(QueryExecutorImpl.java:1333)
at org.postgresql.core.v3.QueryExecutorImpl.fetch(QueryExecutorImpl.java:2383)
... 34 more小结
- 对于不同连接池的参数配置,需要额外注意.
- 关于开启abandon,则会把连接强制关闭掉,这个是全局的
对于在同一个连接执行多个statement的情况,可以使用ResetAbandonedTimer来避免被错误abandon掉连接
- 在springboot中会根据spring.datasource.url自动识别数据库,同时拿到默认的validationQuery,如果该值不为空,则testOnBorrow会被自动设置为true
- 由于poolSweeper是每隔time-between-eviction-runs-millis时间执行一次，而且是checkAbandoned，checkIdle，testAllIdle依次往下执行，由于它是采用timer实现的，因此一旦某个时间点的任务延时了，后续也一并延时，并不能保证每隔time-between-eviction-runs-millis时间执行一次，这点需要额外注意。
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