关于druid:聊聊druid连接池的参数配置

本文次要钻研一下 druid 连接池的参数配置

druid-1.2.11-sources.jar!/com/alibaba/druid/pool/DruidDataSourceFactory.java

public class DruidDataSourceFactory implements ObjectFactory {private static final Log LOG = LogFactory.getLog(DruidDataSourceFactory.class);

    static final int UNKNOWN_TRANSACTIONISOLATION = -1;

    public static final String PROP_DEFAULTAUTOCOMMIT = "defaultAutoCommit";
    public static final String PROP_DEFAULTREADONLY = "defaultReadOnly";
    public static final String PROP_DEFAULTTRANSACTIONISOLATION = "defaultTransactionIsolation";
    public static final String PROP_DEFAULTCATALOG = "defaultCatalog";
    public static final String PROP_DRIVERCLASSNAME = "driverClassName";
    public static final String PROP_MAXACTIVE = "maxActive";
    public static final String PROP_MAXIDLE = "maxIdle";
    public static final String PROP_MINIDLE = "minIdle";
    public static final String PROP_INITIALSIZE = "initialSize";
    public static final String PROP_MAXWAIT = "maxWait";
    public static final String PROP_TESTONBORROW = "testOnBorrow";
    public static final String PROP_TESTONRETURN = "testOnReturn";
    public static final String PROP_TIMEBETWEENEVICTIONRUNSMILLIS = "timeBetweenEvictionRunsMillis";
    public static final String PROP_NUMTESTSPEREVICTIONRUN = "numTestsPerEvictionRun";
    public static final String PROP_MINEVICTABLEIDLETIMEMILLIS = "minEvictableIdleTimeMillis";
    public static final String PROP_PHY_TIMEOUT_MILLIS = "phyTimeoutMillis";
    public static final String PROP_TESTWHILEIDLE = "testWhileIdle";
    public static final String PROP_PASSWORD = "password";
    public static final String PROP_URL = "url";
    public static final String PROP_USERNAME = "username";
    public static final String PROP_VALIDATIONQUERY = "validationQuery";
    public static final String PROP_VALIDATIONQUERY_TIMEOUT = "validationQueryTimeout";
    public static final String PROP_INITCONNECTIONSQLS = "initConnectionSqls";
    public static final String PROP_ACCESSTOUNDERLYINGCONNECTIONALLOWED = "accessToUnderlyingConnectionAllowed";
    public static final String PROP_REMOVEABANDONED = "removeAbandoned";
    public static final String PROP_REMOVEABANDONEDTIMEOUT = "removeAbandonedTimeout";
    public static final String PROP_LOGABANDONED = "logAbandoned";
    public static final String PROP_POOLPREPAREDSTATEMENTS = "poolPreparedStatements";
    public static final String PROP_MAXOPENPREPAREDSTATEMENTS = "maxOpenPreparedStatements";
    public static final String PROP_CONNECTIONPROPERTIES = "connectionProperties";
    public static final String PROP_FILTERS = "filters";
    public static final String PROP_EXCEPTION_SORTER = "exceptionSorter";
    public static final String PROP_EXCEPTION_SORTER_CLASS_NAME = "exception-sorter-class-name";
    public static final String PROP_NAME = "name";
    public static final String PROP_INIT = "init";

    private static final String[] ALL_PROPERTIES = {
            PROP_DEFAULTAUTOCOMMIT,
            PROP_DEFAULTREADONLY,
            PROP_DEFAULTTRANSACTIONISOLATION,
            PROP_DEFAULTCATALOG,
            PROP_DRIVERCLASSNAME,
            PROP_MAXACTIVE,
            PROP_MAXIDLE,
            PROP_MINIDLE,
            PROP_INITIALSIZE,
            PROP_MAXWAIT,
            PROP_TESTONBORROW,
            PROP_TESTONRETURN,
            PROP_TIMEBETWEENEVICTIONRUNSMILLIS,
            PROP_NUMTESTSPEREVICTIONRUN,
            PROP_MINEVICTABLEIDLETIMEMILLIS,
            PROP_TESTWHILEIDLE,
            PROP_PASSWORD,
            PROP_FILTERS,
            PROP_URL,
            PROP_USERNAME,
            PROP_VALIDATIONQUERY,
            PROP_VALIDATIONQUERY_TIMEOUT,
            PROP_INITCONNECTIONSQLS,
            PROP_ACCESSTOUNDERLYINGCONNECTIONALLOWED,
            PROP_REMOVEABANDONED,
            PROP_REMOVEABANDONEDTIMEOUT,
            PROP_LOGABANDONED,
            PROP_POOLPREPAREDSTATEMENTS,
            PROP_MAXOPENPREPAREDSTATEMENTS,
            PROP_CONNECTIONPROPERTIES,
            PROP_EXCEPTION_SORTER,
            PROP_EXCEPTION_SORTER_CLASS_NAME,
            PROP_INIT,
            PROP_NAME,

            "druid.timeBetweenLogStatsMillis",
            "druid.stat.sql.MaxSize",
            "druid.clearFiltersEnable",
            "druid.resetStatEnable", //
            "druid.notFullTimeoutRetryCount", //
            "druid.maxWaitThreadCount", //
            "druid.failFast", //
            "druid.phyTimeoutMillis", //
            "druid.wall.tenantColumn", //
            "druid.wall.updateAllow", //
            "druid.wall.deleteAllow", //
            "druid.wall.insertAllow", //
            "druid.wall.selelctAllow", //
            "druid.wall.multiStatementAllow", //
    };

    //......
}

DruidDataSourceFactory 的 ALL_PROPERTIES 常量定义了所有反对的可配置项

com/alibaba/druid/spring/boot/autoconfigure/DruidDataSourceWrapper.java

@ConfigurationProperties("spring.datasource.druid")
public class DruidDataSourceWrapper extends DruidDataSource implements InitializingBean {
    @Autowired
    private DataSourceProperties basicProperties;

    @Override
    public void afterPropertiesSet() throws Exception {
        //if not found prefix 'spring.datasource.druid' jdbc properties ,'spring.datasource' prefix jdbc properties will be used.
        if (super.getUsername() == null) {super.setUsername(basicProperties.determineUsername());
        }
        if (super.getPassword() == null) {super.setPassword(basicProperties.determinePassword());
        }
        if (super.getUrl() == null) {super.setUrl(basicProperties.determineUrl());
        }
        if (super.getDriverClassName() == null) {super.setDriverClassName(basicProperties.getDriverClassName());
        }
    }

    @Autowired(required = false)
    public void autoAddFilters(List<Filter> filters){super.filters.addAll(filters);
    }

    /**
     * Ignore the 'maxEvictableIdleTimeMillis &lt; minEvictableIdleTimeMillis' validate,
     * it will be validated again in {@link DruidDataSource#init()}.
     *
     * for fix issue #3084, #2763
     *
     * @since 1.1.14
     */
    @Override
    public void setMaxEvictableIdleTimeMillis(long maxEvictableIdleTimeMillis) {
        try {super.setMaxEvictableIdleTimeMillis(maxEvictableIdleTimeMillis);
        } catch (IllegalArgumentException ignore) {super.maxEvictableIdleTimeMillis = maxEvictableIdleTimeMillis;}
    }
}

DruidDataSourceWrapper 继承了 DruidDataSource，在 afterPropertiesSet 的时候会应用 DataSourceProperties 的 username、password、url、driverClassName，其余配置在 DruidDataSource 中

com/alibaba/druid/pool/DruidDataSource.java

public class DruidDataSource extends DruidAbstractDataSource implements DruidDataSourceMBean, ManagedDataSource, Referenceable, Closeable, Cloneable, ConnectionPoolDataSource, MBeanRegistration {

    private boolean                          useGlobalDataSourceStat   = false;
    private boolean                          logDifferentThread        = true;
    private volatile boolean                 keepAlive                 = false;
    private boolean                          asyncInit                 = false;
    protected boolean                        killWhenSocketReadTimeout = false;
    protected boolean                        checkExecuteTime          = false;        
}

DruidDataSource 继承了 DruidAbstractDataSource，它只定义了 keepAlive、asyncInit 等几个配置，其它大部分配置在 DruidAbstractDataSource 中

com/alibaba/druid/pool/DruidAbstractDataSource.java

public abstract class DruidAbstractDataSource extends WrapperAdapter implements DruidAbstractDataSourceMBean, DataSource, DataSourceProxy, Serializable {
    protected volatile int initialSize = DEFAULT_INITIAL_SIZE;
    public static final int DEFAULT_INITIAL_SIZE = 0;

    protected volatile int maxActive = DEFAULT_MAX_ACTIVE_SIZE;
    public static final int DEFAULT_MAX_ACTIVE_SIZE = 8;

    protected volatile int minIdle = DEFAULT_MIN_IDLE;
    public static final int DEFAULT_MIN_IDLE = 0;

    protected volatile int maxIdle = DEFAULT_MAX_IDLE;
    public static final int DEFAULT_MAX_IDLE = 8;

    protected volatile long maxWait = DEFAULT_MAX_WAIT;
    public static final int DEFAULT_MAX_WAIT = -1;

    protected volatile String validationQuery = DEFAULT_VALIDATION_QUERY;
    public static final String DEFAULT_VALIDATION_QUERY = null;   

    protected volatile int validationQueryTimeout = -1;

    protected volatile boolean testOnBorrow = DEFAULT_TEST_ON_BORROW;
    public static final boolean DEFAULT_TEST_ON_BORROW = false;

    protected volatile boolean testOnReturn = DEFAULT_TEST_ON_RETURN;
    public static final boolean DEFAULT_TEST_ON_RETURN = false;

    protected volatile boolean testWhileIdle = DEFAULT_WHILE_IDLE;
    public static final boolean DEFAULT_WHILE_IDLE = true;

    protected volatile int maxPoolPreparedStatementPerConnectionSize = 10;

    protected volatile long timeBetweenEvictionRunsMillis = DEFAULT_TIME_BETWEEN_EVICTION_RUNS_MILLIS;
    public static final long DEFAULT_TIME_BETWEEN_EVICTION_RUNS_MILLIS = 60 * 1000L;

    protected volatile int numTestsPerEvictionRun = DEFAULT_NUM_TESTS_PER_EVICTION_RUN;
    public static final int DEFAULT_NUM_TESTS_PER_EVICTION_RUN = 3;

    protected volatile long minEvictableIdleTimeMillis = DEFAULT_MIN_EVICTABLE_IDLE_TIME_MILLIS;
    public static final long DEFAULT_MIN_EVICTABLE_IDLE_TIME_MILLIS = 1000L * 60L * 30L;

    protected volatile long maxEvictableIdleTimeMillis = DEFAULT_MAX_EVICTABLE_IDLE_TIME_MILLIS;
    public static final long DEFAULT_MAX_EVICTABLE_IDLE_TIME_MILLIS = 1000L * 60L * 60L * 7;

    protected volatile long keepAliveBetweenTimeMillis = DEFAULT_TIME_BETWEEN_EVICTION_RUNS_MILLIS * 2;

    protected volatile long phyTimeoutMillis = DEFAULT_PHY_TIMEOUT_MILLIS;
    public static final long DEFAULT_PHY_TIMEOUT_MILLIS = -1;

    protected volatile long timeBetweenConnectErrorMillis = DEFAULT_TIME_BETWEEN_CONNECT_ERROR_MILLIS;
    public static final long DEFAULT_TIME_BETWEEN_CONNECT_ERROR_MILLIS = 500;

}

DruidAbstractDataSource 定义的配置及其默认值如下

类别	配置项	默认值	阐明
数量	initialSize	0	–
数量	maxActive	8	–
数量	minIdle	0	–
数量	maxIdle	8	–
数量	maxPoolPreparedStatementPerConnectionSize	10	–
衰弱检测	validationQuery	null	mysql 默认为 SELECT 1
衰弱检测	validationQueryTimeout	-1	单位秒，mysql 默认 1s
衰弱检测	testOnBorrow	false	–
衰弱检测	testOnReturn	false	–
衰弱检测	testOnReturn	false	–
衰弱检测	testWhileIdle	true	–
evict	timeBetweenEvictionRunsMillis	60s	–
evict	numTestsPerEvictionRun	3	–
evict	minEvictableIdleTimeMillis	30 分钟	–
evict	maxEvictableIdleTimeMillis	7 小时	–
超时	maxWait	-1	单位毫秒
超时	keepAliveBetweenTimeMillis	120s	2* DEFAULT_TIME_BETWEEN_EVICTION_RUNS_MILLIS
超时	phyTimeoutMillis	-1	–
超时	queryTimeout	0	–
超时	transactionQueryTimeout	0	–
谬误	timeBetweenConnectErrorMillis	500ms	–
连贯泄露	removeAbandoned	false	–
连贯泄露	removeAbandonedTimeoutMillis	300s	–

获取连贯时，若 maxWait 大于 0 则走的 pollLast(nanos)，其中 maxWait 是作为 notEmpty.awaitNanos 参数，毫秒转为 nacos，若为正数则取 0；若 maxWait 小于等于 0 则走的 takeLast，执行的是 notEmpty.await()，即阻塞期待

druid 连接池的配置次要是在 DruidDataSource 中，而 DruidDataSource 继承了 DruidAbstractDataSource，它只定义了 keepAlive、asyncInit 等几个配置，其它大部分配置在 DruidAbstractDataSource 中，没有独自的一个配置类，而后默认只开启了 testWhileIdle，maxWait 默认为 -1；因此倡议强制配置 maxWait 为负数 ( 单位毫秒)；在并发量比拟大的场景，若要保障连接池的稳固数量则能够将 minIdle 配置为与 maxIdle 一样。

关于druid:聊聊druid连接池的参数配置

序

DruidDataSourceFactory

DruidDataSourceWrapper

DruidDataSource

DruidAbstractDataSource

小结