错误: An SQL error occurred when executing the following query: .

org.opencms.db.CmsDbSqlException: An SQL error occurred when executing the following query: . 
	at org.opencms.db.generic.CmsVfsDriver.readResource(CmsVfsDriver.java:1942)
	at org.opencms.db.CmsDriverManager.readResource(CmsDriverManager.java:6462)
	at org.opencms.db.CmsSecurityManager.readResource(CmsSecurityManager.java:5849)
	at org.opencms.db.CmsSecurityManager.readResource(CmsSecurityManager.java:4034)
	at org.opencms.file.CmsObject.readResource(CmsObject.java:3529)
.....

最近opencms老是出现读取数据库慢,半天刷新不出来,最后出现上面的异常.
看异常信息是数据库的问题,涉及到连接池.自己也不敢乱改.于是google,发现原来修改opencms.properties文件的一个配置就可以了,如下代码

# action to take when the pool is exhausted {grow|block|fail}
db.pool.default.whenExhaustedAction=block

把 block 修改成 grow