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本文次要钻研一下jedis连接池的参数配置
JedisConfig
redis/clients/jedis/JedisPoolConfig.java
public class JedisPoolConfig extends GenericObjectPoolConfig<Jedis> { public JedisPoolConfig() { // defaults to make your life with connection pool easier :) setTestWhileIdle(true); setMinEvictableIdleTimeMillis(60000); setTimeBetweenEvictionRunsMillis(30000); setNumTestsPerEvictionRun(-1); }}JedisPoolConfig继承了GenericObjectPoolConfig，同时默认配置了testWhileIdle为true(默认为false)，minEvictableIdleTime为60s(默认为30分钟)，timeBetweenEvictionRuns为30s(默认为-1)，numTestsPerEvictionRun为-1(即检测所有闲暇连贯，默认值为3)
GenericObjectPoolConfig
org/apache/commons/pool2/impl/GenericObjectPoolConfig.java
public class GenericObjectPoolConfig<T> extends BaseObjectPoolConfig<T> { /** * The default value for the {@code maxTotal} configuration attribute. * @see GenericObjectPool#getMaxTotal() */ public static final int DEFAULT_MAX_TOTAL = 8; /** * The default value for the {@code maxIdle} configuration attribute. * @see GenericObjectPool#getMaxIdle() */ public static final int DEFAULT_MAX_IDLE = 8; /** * The default value for the {@code minIdle} configuration attribute. * @see GenericObjectPool#getMinIdle() */ public static final int DEFAULT_MIN_IDLE = 0; private int maxTotal = DEFAULT_MAX_TOTAL; private int maxIdle = DEFAULT_MAX_IDLE; private int minIdle = DEFAULT_MIN_IDLE;}GenericObjectPoolConfig继承了BaseObjectPoolConfig，其maxTotal为8，maxIdle为8，minIdle为0
BaseObjectPoolConfig
org/apache/commons/pool2/impl/BaseObjectPoolConfig.java
public abstract class BaseObjectPoolConfig<T> extends BaseObject implements Cloneable { private boolean lifo = DEFAULT_LIFO; public static final boolean DEFAULT_LIFO = true; private boolean fairness = DEFAULT_FAIRNESS; public static final boolean DEFAULT_FAIRNESS = false; private Duration maxWaitDuration = DEFAULT_MAX_WAIT; public static final Duration DEFAULT_MAX_WAIT = Duration.ofMillis(-1L); private Duration minEvictableIdleDuration = DEFAULT_MIN_EVICTABLE_IDLE_TIME; public static final Duration DEFAULT_MIN_EVICTABLE_IDLE_TIME = Duration.ofMillis(1000L * 60L * 30L); private Duration evictorShutdownTimeoutDuration = DEFAULT_EVICTOR_SHUTDOWN_TIMEOUT; public static final Duration DEFAULT_EVICTOR_SHUTDOWN_TIMEOUT = Duration.ofMillis(10L * 1000L); private Duration softMinEvictableIdleDuration = DEFAULT_SOFT_MIN_EVICTABLE_IDLE_TIME; public static final Duration DEFAULT_SOFT_MIN_EVICTABLE_IDLE_TIME = Duration.ofMillis(-1); private int numTestsPerEvictionRun = DEFAULT_NUM_TESTS_PER_EVICTION_RUN; public static final int DEFAULT_NUM_TESTS_PER_EVICTION_RUN = 3; private EvictionPolicy<T> evictionPolicy; // Only 2.6.0 applications set this private String evictionPolicyClassName = DEFAULT_EVICTION_POLICY_CLASS_NAME; public static final String DEFAULT_EVICTION_POLICY_CLASS_NAME = DefaultEvictionPolicy.class.getName(); private boolean testOnCreate = DEFAULT_TEST_ON_CREATE; public static final boolean DEFAULT_TEST_ON_CREATE = false; private boolean testOnBorrow = DEFAULT_TEST_ON_BORROW; public static final boolean DEFAULT_TEST_ON_BORROW = false; private boolean testOnReturn = DEFAULT_TEST_ON_RETURN; public static final boolean DEFAULT_TEST_ON_RETURN = false; private boolean testWhileIdle = DEFAULT_TEST_WHILE_IDLE; public static final boolean DEFAULT_TEST_WHILE_IDLE = false; private Duration durationBetweenEvictionRuns = DEFAULT_TIME_BETWEEN_EVICTION_RUNS; public static final Duration DEFAULT_TIME_BETWEEN_EVICTION_RUNS = Duration .ofMillis(-1L); private boolean blockWhenExhausted = DEFAULT_BLOCK_WHEN_EXHAUSTED; public static final boolean DEFAULT_BLOCK_WHEN_EXHAUSTED = true; private boolean jmxEnabled = DEFAULT_JMX_ENABLE; public static final boolean DEFAULT_JMX_ENABLE = true; // TODO Consider changing this to a single property for 3.x private String jmxNamePrefix = DEFAULT_JMX_NAME_PREFIX; public static final String DEFAULT_JMX_NAME_PREFIX = "pool"; private String jmxNameBase = DEFAULT_JMX_NAME_BASE; public static final String DEFAULT_JMX_NAME_BASE = null;}BaseObjectPoolConfig定义了lifo(默认为true)、fairness(默认为false)、maxWaitDuration(默认为-1)、minEvictableIdleDuration(默认为30分钟)、evictorShutdownTimeoutDuration(默认为10s)、softMinEvictableIdleDuration(默认为-1)、numTestsPerEvictionRun(默认为3)、evictionPolicyClassName(默认为DefaultEvictionPolicy.class.getName())、testOnCreate(默认为false)、testOnBorrow(默认为false)、testOnReturn(默认为false)、testWhileIdle(默认为false)、durationBetweenEvictionRuns(默认为-1)、blockWhenExhausted(默认为true)、jmxEnabled(默认为true)、jmxNamePrefix(默认为pool)、jmxNameBase(默认为null)
maxWaitDuration
org/apache/commons/pool2/impl/GenericObjectPool.java
if (blockWhenExhausted) { if (p == null) { if (borrowMaxWaitDuration.isNegative()) { p = idleObjects.takeFirst(); } else { p = idleObjects.pollFirst(borrowMaxWaitDuration); } } if (p == null) { throw new NoSuchElementException(appendStats( "Timeout waiting for idle object, borrowMaxWaitDuration=" + borrowMaxWaitDuration)); } }borrow的时候在blockWhenExhausted为true时应用，-1的话则应用takeFirst办法，否则应用pollFirst(borrowMaxWaitDuration)办法
evict
getNumTests
org/apache/commons/pool2/impl/GenericObjectPool.java
/** * Calculates the number of objects to test in a run of the idle object * evictor. * * @return The number of objects to test for validity */ private int getNumTests() { final int numTestsPerEvictionRun = getNumTestsPerEvictionRun(); if (numTestsPerEvictionRun >= 0) { return Math.min(numTestsPerEvictionRun, idleObjects.size()); } return (int) (Math.ceil(idleObjects.size() / Math.abs((double) numTestsPerEvictionRun))); }当numTestsPerEvictionRun为-1时，返回的是idleObjects.size()
EvictionConfig
org/apache/commons/pool2/impl/EvictionConfig.java
public class EvictionConfig { private static final Duration MAX_DURATION = Duration.ofMillis(Long.MAX_VALUE); private final Duration idleEvictDuration; private final Duration idleSoftEvictDuration; private final int minIdle; /** * Creates a new eviction configuration with the specified parameters. * Instances are immutable. * * @param idleEvictDuration Expected to be provided by * {@link BaseGenericObjectPool#getMinEvictableIdleDuration()} * @param idleSoftEvictDuration Expected to be provided by * {@link BaseGenericObjectPool#getSoftMinEvictableIdleDuration()} * @param minIdle Expected to be provided by * {@link GenericObjectPool#getMinIdle()} or * {@link GenericKeyedObjectPool#getMinIdlePerKey()} * @since 2.10.0 */ public EvictionConfig(final Duration idleEvictDuration, final Duration idleSoftEvictDuration, final int minIdle) { this.idleEvictDuration = PoolImplUtils.isPositive(idleEvictDuration) ? idleEvictDuration : MAX_DURATION; this.idleSoftEvictDuration = PoolImplUtils.isPositive(idleSoftEvictDuration) ? idleSoftEvictDuration : MAX_DURATION; this.minIdle = minIdle; } //......} evict办法会结构EvictionConfig，minEvictableIdleDuration默认为30分钟；这里次要是针对正数进行了判断，正数则取的Long.MAX_VALUE；即softMinEvictableIdleDuration默认为-1，转换过去就是Long.MAX_VALUE
final EvictionConfig evictionConfig = new EvictionConfig( getMinEvictableIdleDuration(), getSoftMinEvictableIdleDuration(), getMinIdle());DefaultEvictionPolicy
org/apache/commons/pool2/impl/DefaultEvictionPolicy.java
public class DefaultEvictionPolicy<T> implements EvictionPolicy<T> { @Override public boolean evict(final EvictionConfig config, final PooledObject<T> underTest, final int idleCount) { // @formatter:off return (config.getIdleSoftEvictDuration().compareTo(underTest.getIdleDuration()) < 0 && config.getMinIdle() < idleCount) || config.getIdleEvictDuration().compareTo(underTest.getIdleDuration()) < 0; // @formatter:on }}DefaultEvictionPolicy的evict办法在idleCount大于minIdle且idleDuration大于idleSoftEvictDuration(默认为Long.MAX_VALUE)返回true，或者obj的idleDuration大于minEvictableIdleDuration(默认为30分钟)返回true
durationBetweenEvictionRuns
org/apache/commons/pool2/impl/BaseGenericObjectPool.java
public final void setTimeBetweenEvictionRuns(final Duration timeBetweenEvictionRuns) { this.durationBetweenEvictionRuns = PoolImplUtils.nonNull(timeBetweenEvictionRuns, BaseObjectPoolConfig.DEFAULT_TIME_BETWEEN_EVICTION_RUNS); startEvictor(this.durationBetweenEvictionRuns); } final void startEvictor(final Duration delay) { synchronized (evictionLock) { final boolean isPositiverDelay = PoolImplUtils.isPositive(delay); if (evictor == null) { // Starting evictor for the first time or after a cancel if (isPositiverDelay) { // Starting new evictor evictor = new Evictor(); EvictionTimer.schedule(evictor, delay, delay); } } else if (isPositiverDelay) { // Stop or restart of existing evictor: Restart synchronized (EvictionTimer.class) { // Ensure no cancel can happen between cancel / schedule calls EvictionTimer.cancel(evictor, evictorShutdownTimeoutDuration, true); evictor = null; evictionIterator = null; evictor = new Evictor(); EvictionTimer.schedule(evictor, delay, delay); } } else { // Stopping evictor EvictionTimer.cancel(evictor, evictorShutdownTimeoutDuration, false); } } }setTimeBetweenEvictionRuns办法会durationBetweenEvictionRuns(默认为-1)去startEvictor；当改值为正数时则执行EvictionTimer.cancel，即不启动evictor线程cancel
org/apache/commons/pool2/impl/EvictionTimer.java
/** * Removes the specified eviction task from the timer. * * @param evictor Task to be cancelled. * @param timeout If the associated executor is no longer required, how * long should this thread wait for the executor to * terminate? * @param restarting The state of the evictor. */ static synchronized void cancel(final BaseGenericObjectPool<?>.Evictor evictor, final Duration timeout, final boolean restarting) { if (evictor != null) { evictor.cancel(); remove(evictor); } if (!restarting && executor != null && taskMap.isEmpty()) { executor.shutdown(); try { executor.awaitTermination(timeout.toMillis(), TimeUnit.MILLISECONDS); } catch (final InterruptedException e) { // Swallow // Significant API changes would be required to propagate this } executor.setCorePoolSize(0); executor = null; } }evictorShutdownTimeoutDuration即executor.awaitTermination的timeout参数
小结
| 参数类别 | 参数值 | jedisConfig值 | commons-pool默认值 | 解释 |
|---|---|---|---|---|
| 根本 | lifo | true | true | 后进先出 |
| 根本 | fairness | false | false | 非偏心机制 |
| 数量 | maxTotal | 8 | - | 最大连接数 |
| 数量 | maxIdle | 8 | - | 最大空间连接数 |
| 数量 | minIdle | 0 | - | 起码闲暇连接数 |
| 阻塞获取 | blockWhenExhausted | true | true | 连接池耗尽时，获取连贯是否阻塞期待 |
| 阻塞获取 | maxWaitMillis | -1 | -1 | blockWhenExhausted为true时阻塞期待多久 |
| 衰弱检测 | testOnCreate | fasle | fasle | 创立连贯的时候检测 |
| 衰弱检测 | testOnBorrow | false | false | 借用连贯的时候检测 |
| 衰弱检测 | testOnReturn | false | false | 偿还连贯的时候检测 |
| 衰弱检测 | testWhileIdle | true | false | 在闲暇连贯检测时检测 |
| evict | durationBetweenEvictionRuns | 30秒 | -1 | evictor线程运行距离，-1为不运行 |
| evict | minEvictableIdleDuration | 60秒 | 30分钟 | 连贯闲暇的最小工夫 |
| evict | softMinEvictableIdleDuration | -1 | -1 | -1即Long.MAX_VALUE，它与idleCount>minIdle条件一起思考 |
| evict | numTestsPerEvictionRun | -1 | 3 | 每次闲暇连贯回收器线程(如果有)运行时查看的连贯数量, -1示意全副 |
| evict | evictionPolicyClassName | DefaultEvictionPolicy | DefaultEvictionPolicy | 判断是否须要evict的PolicyClass |
| evict | evictorShutdownTimeoutDuration | 10s | 10s | 敞开evictor线程池的等待时间 |
| jmx | jmxEnabled | true | true | 是否开启jmx |
| jmx | jmxNamePrefix | pool | pool | jmx名称前缀 |
| jmx | jmxNameBase | null | null | null示意由pool本人定义jmxNameBase |
JedisConfig默认帮咱们配置了testWhileIdle为true(
默认为false)，minEvictableIdleTime为60s(默认为30分钟)，timeBetweenEvictionRuns为30s(默认为-1)，numTestsPerEvictionRun为-1(即检测所有闲暇连贯，默认值为3)，利用evictor线程来检测闲暇连贯的衰弱状况另外由聊聊jedis的return行为这篇剖析能够得悉在执行命令时若redis出问题，Jedis自身会标记底层connection为broken，在finally偿还时会destory连贯，保障连接池连贯最终都会被清空重建。
另外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把minIdle设置成与maxTotal和maxIdle一样即可；若不想因为idle工夫被频繁destory则能够设置minEvictableIdleTime为-1，evict办法始终返回false，evictor线程始终走的是testWhileIdle的逻辑；maxWaitMillis要设置一个正当值防止连接池耗尽阻塞线程，或者间接设置blockWhenExhausted为false
doc
- GenericObjectPool参数解析
- JedisPool资源池优化
- 一次拜访Redis延时高问题排查与总结
- 实战总结｜一次拜访Redis延时高问题排查与总结（续）