Java heap dump OQL samples - where - 认真生活每一天

where 可以包含:

=, <=, >, <, [ NOT ] LIKE, [ NOT ] IN, IMPLEMENTS (relational operations)
AND OR != , =

字段可以 [<alias>. ] <field> . <field>. <field>

SELECT * FROM java.net.URL u where u.port = 443
SELECT * FROM java.net.URL u where toString(u.host) = "api.google.com"
SELECT FROM java.net.URL u where u.@displayName like ".api.google.com.*"
SELECT FROM "com.tianxiaohui." u where toString(u) like ".Metrics." //正则
SELECT s.address.holder.hostName.toString(), s.timeout FROM java.net.SocksSocketImpl s WHERE (s.port = 443) //socket 的地址和 timeout 时间
SELECT toString(u.string) FROM java.net.URI u WHERE (toString(u.schemeSpecificPart) LIKE ".+google.com.+")
SELECT x.capacity FROM java.nio.DirectByteBuffer x WHERE ((toString(x.att) = "null") and (toString(x.cleaner) != "null") and (x.capacity >= (1024 * 1024)))
SELECT DISTINCT objects x.this$0 FROM java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask x
SELECT distinct objects x FROM java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask x WHERE (x.this$0.toString() LIKE ".+0x468369b50")
SELECT * FROM INSTANCEOF java.lang.Object t WHERE (toHex(t.@objectAddress) >= "0xfbd4c000" AND toHex(t.@objectAddress) <= "0xfce94050") //一段地址空间中的所有对象
select * from java.nio.DirectByteBuffer x where x.capacity > 65535 and x.cleaner != null

如何在MAT里使用OQL 做到group by - count的效果?
使用OQL之后, 在OQL的Tab 里, 可以看到菜单栏有个导出的Icon, 可以导出为HTMl, CSV, TXT. 导出CSV,使用Excel做count.

如果 0x789342b78 对应的地址是一个类class(不是instance), 那么可以用下面这种查法:
select * from 0x789342b78

如果要查询某个 Class 的 static 字段里面的数据:
SELECT FROM java.lang.Class x where x.toString() LIKE ".+com.tianxiaohui.platform.config.impl.ConfigProvider."

如果要查询一个抽象类的具体实现:
select * from INSTANCEOF java.net.AbstractPlainSocketImpl

内置函数:

Java heap dump OQL samples - where