Unknown lock type TC

From: Adon Keber <adon_at_cool.zg.iskon.hr>
Date: 16 Oct 2001 17:35:08 GMT
Message-ID: <slrn9sos2u.2js.adon@cool.zg.iskon.hr>

One of our applications are working badly and during research of a problem I have encountered lock type TC in v$lock

First indication of problem was:

select type,count(*)
from v$lock
group by type

TY COUNT(*)
-- ----------

MR         33
PS          8
RT          1
TM          7
TS          2
TX          5

It seems that some SELECT query locks itself somehow. Lock requested is usually S/ROW-X(SSX) and lock mode is EXCLUSIVE

Final indication of strange problem is:

SELECT ksqsttyp "Lock",
ksqstget "Gets",
ksqstwat "Waits"
FROM X$KSQST where KSQSTWAT>0

and result:

Lo Gets Waits
-- ---------- ----------

PE    3934019          3
PS    8389739          1
TC    1331031       2649
TM    3798880         64
TX    1780228         18

So applications are mainly waiting on TC lock.

I couldn't find any reference of TC lock type except on metalink where Oracle's support person admits that he can't find reference of TC lock (Doc ID 101144.998)

Thanks,
adon Received on Tue Oct 16 2001 - 12:35:08 CDT