expdp and ORA-01555
- From: richa03@xxxxxxxxx
- To: oracle-l <oracle-l@xxxxxxxxxxxxx>
- Date: Tue, 26 Aug 2008 08:49:40 -0700
64-bit 10.2.0.3 on Solaris 10 x86
When trying to export a single table, we get:
ORA-01555: snapshot too old: rollback segment number with name "" too small
The table contains out of line LOBs using PCTVERSION of 10, however, these
LOBs are never updated, so the PCTVERSION should not be the issue.
[This has been proven through the MON_MODS$ table using the OBJECT_ID column
of DBA_OBJECTS - see below]
We have scanned this table per Oracle Note 452341.1 and there is no
corruption.
We have created a larger undo segment - from 1GB to 5GB.
We set event 1555 to dump errorstack at level 3 and have the trace file.
We have changed undo_retention from 900 to 21140 per v$undostat.
The columns SSOLDERRCNT and NOSPACEERRCNT are 0.
Furthermore, the columns UNXPSTEALCNT & EXPSTEALCNT are all 0 and the column
MAXQUERYLEN was not over the setting of the undo_retention parameter (21140
- the high was 8069) during the export.
The export fails at about 141009977344 bytes (5 runs, sometimes earlier with
less bytes).
The table is about 100M records and about 275GB. It's structure is:
Name Null? Type
----------------------------------------- -------- --------------
TRHS_PKEY NOT NULL NUMBER
TRHS_SEQ NOT NULL NUMBER
TRAN_KEY NOT NULL NUMBER
BSTP_KEY NUMBER
TRSP_KEY NUMBER
TRHS_DESC NOT NULL VARCHAR2(256)
TRHS_DOC_URL VARCHAR2(512)
TRHS_DOC BLOB
TRHS_DOC_SIZE NOT NULL NUMBER
TRHS_ZIPPED NOT NULL NUMBER
TRHS_CONTENT_TYPE VARCHAR2(128)
TRHS_CREATED_DATE NOT NULL DATE
The table is insert only - about 700 records per min.
select * from SYS.MON_MODS$ where OBJ# = 32716;
OBJ# INSERTS UPDATES DELETES TIMESTAMP FLAGS
DROP_SEGMENTS
---------- ---------- ---------- ---------- --------- ----------
-------------
32716 36837918 0 1320167 26-AUG-08 0
0
The export was tested in a test environment (without load) and succeeded -
170341232640 bytes.
Stack trace:
Summary Stack (to Full stack) (to Function List)
koklierr NAME: koklisdisk - KOK Lob Internal Set DISK part of locator.
kluuldcs
kluprd
kluuscn
kluuld
kpodpuls
opiodr OPIODR: ORACLE code request driver - route the current request
We have an open SR with Oracle, but, well, you know...
We can try to simulate load on this object, however this will be difficult
if not impossible in test.
Under insert, I would expect the internal LOB index to be updated - does
this count against undo?
If so, where is this undo stored - normal undo segments or internal to the
LOB object (like the pctversion space)?
Does expdp lock this undo to ensure consistency?
TIA
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