关于plsql 部分表查询不出来的问题

环境 linux +rac

连接工具plsql 8.0.1

在连接数据库之后,执行select * from v$session 一直处于查询状态,出不来结果

在sqlplus 下执行正常.

PS:部分表(用户创建的表)是这种情况,但也有一部分是正常.

此问题 在askmaclean 中提问过

细作了一番实验,发现有几个特征

1、select * from t 查询不出数据,一直处于查询状态

但是把t的字段列举出几个，如select a,b,c from t 是可以查询出数据

或者 select * from t where rownum<10 也能查出数据，但也有表采取以上两种方式仍然查不出数据。

2、当plsql的客户端和数据库服务器在同一个网段时，则不出现此问题。

3、据开发人员介绍在元旦之前是没问题，在元旦期间，中间路由加了防火墙或者调整了网络，之后就出现了这种现象。

4、把tnsname.ora中的host 改为IP，结果还是一样。

5、数据库的两个用户都是这种情况

此问题应该与服务端无关，应该是客户端网络设置的问题。

（续）

这个问题在http://cqsztech.cqbayuan.com/bbs/dispbbs.asp?BoardID=4&ID=107&Page=1 中能找到答案

网关的防火墙是JUNIPER防火墙，在防火墙上取消JUNIPER防火墙应用层网关对SQL的拦截

Metalink ID 1293202.1

High Virtual Circuit Wait Running SQL Through a Juniper Firewall [ID 1293202.1]
修改时间 18-MAR-2011     类型 PROBLEM     状态 PUBLISHED

In this Document   Symptoms   Changes   Cause   Solution   References
Applies to:
Oracle Net Services - Version: 9.2.0.1 to 11.2.0.2 - Release: 9.2 to 11.2
Information in this document applies to any platform.
Symptoms

From DBControl, High 'virtual circuit wait' is seen on a 'SELECT' SQL.

From ASH Report in 65 minutes elapsed time:
Top User Events

Event                "Event Class"      % Event "Avg Active Sessions"
virtual circuit wait  Network           98.32    7.99

The database is experiencing low performance.

Changes
Firewall policy was implemented for security purposes.

Firewall Device: Juniper Firewall  SSG-520 with Firmware Version 6.2.0 R4.0 .
Cause

"SQL" feature in Juniper Firewall Application Layer Gateway (ALG) is causing the hang.  This feature is documented as a known issue in several other documents:

Document 1075432.1 - Archive Log Shipments Failing in Environment With Juniper Firewall (Doc ID Document 1068158.1 - Shared Server Connections Hung, Waiting on Virtual Circuit Status via Juniper Firewall

Solution
Disable "SQL" feature in Juniper Firewall.

Solution Step:
From the Admin Interface in Juniper Web Interface,
under Security -> Deep Inspection -> ALG (Application Layer Gateway),

Deselect the "SQL" feature (disable the feature).

The result is as in following graph: