只读库状态下持续执行更新语句poolingCount数量增长

dbtype:mysql mysql dbversion: 5.7 druid verion: 1.2.16 jdk verion: 1.8.0 error sql: update / insert testcase code: stacktrace info: error info:

java.sql.SQLException: The MySQL server is running with the --read-only option so it cannot execute this statement
        at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:964)
        at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3970)
        at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3906)
        at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2524)
        at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2677)
        at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2549)
        at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1861)
        at com.mysql.jdbc.PreparedStatement.execute(PreparedStatement.java:1192)
        at com.alibaba.druid.filter.FilterChainImpl.preparedStatement_execute(FilterChainImpl.java:3446)
        at com.alibaba.druid.filter.FilterEventAdapter.preparedStatement_execute(FilterEventAdapter.java:434)
        at com.alibaba.druid.filter.FilterChainImpl.preparedStatement_execute(FilterChainImpl.java:3444)
        at com.alibaba.druid.wall.WallFilter.preparedStatement_execute(WallFilter.java:638)
        at com.alibaba.druid.filter.FilterChainImpl.preparedStatement_execute(FilterChainImpl.java:3444)
        at com.alibaba.druid.filter.FilterEventAdapter.preparedStatement_execute(FilterEventAdapter.java:434)
        at com.alibaba.druid.filter.FilterChainImpl.preparedStatement_execute(FilterChainImpl.java:3444)
        at com.alibaba.druid.proxy.jdbc.PreparedStatementProxyImpl.execute(PreparedStatementProxyImpl.java:152)
        at com.alibaba.druid.pool.DruidPooledPreparedStatement.execute(DruidPooledPreparedStatement.java:483)
        at org.apache.ibatis.executor.statement.PreparedStatementHandler.update(PreparedStatementHandler.java:46)
        at org.apache.ibatis.executor.statement.RoutingStatementHandler.update(RoutingStatementHandler.java:74)
        at org.apache.ibatis.executor.SimpleExecutor.doUpdate(SimpleExecutor.java:50)
        at org.apache.ibatis.executor.BaseExecutor.update$original$AVH4eVIa(BaseExecutor.java:117)
        at org.apache.ibatis.executor.BaseExecutor.update$original$AVH4eVIa$accessor$ENOm0MkW(BaseExecutor.java)

只读库状态（SET GLOBAL READ_ONLY=1）下，有定时任务持续更新（update / insert）该库，监控发现poolingCount数量持续缓慢增长，直到最大池大小，此时查询类语句可正常执行，且总体语句执行并发不高。如何配置避免上述场景下池连接数不持续增长？

alibaba / druid

只读库状态下持续执行更新语句poolingCount数量增长 #6006