V$Lock Doesn't Show Tx/Tm Lock Information For Attached XA Transaction After Upgrade to 10g (Doc ID 433183.1)

Last updated on FEBRUARY 08, 2017

Applies to:

Oracle Database - Enterprise Edition - Version 10.1.0.2 to 10.2.0.3 [Release 10.1 to 10.2]
Information in this document applies to any platform.

Symptoms

After upgrading to Oracle server 10g, the V$LOCK view only shows a single TM lock entry for an XA transaction waiting on a lock from another XA transaction. Note, both transactions are attached (XA transactions can be active but not attached to any server processes; this state is called 'detached' and in that case it is expected that no information for the transaction will show up in V$LOCK). The 9.2 V$LOCK shows two TM and 2 TX locks, which makes it easy to figure out the waiting and blocking sessions.

For example, in 9.2 the output of a query against V$LOCK for this situation will look like:

ID TY ID1 ID2 LMODE REQUEST CTIME
---------- -- ---------- ---------- ---------- ---------- ----------
7 TM 25054 0 3 0 3
7 TX 327682 121 6 0 3
11 TM 25054 0 3 0 3
11 TX 327682 121 0 6 3

This easily allows identification of the blocking session.


In contrast, for 10g the output of a query against V$LOCK for this situation will look similar to:

SID TY ID1 ID2 LMODE REQUEST CTIME
---------- -- ---------- ---------- ---------- ---------- ----------
27 TX 1572906 49 0 6 27

There is no reference to the blocking session anymore.

Changes

Upgrade to 10g

Cause

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