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Oracle 9i Upgrade and Migration Support
Migration from Oracle 8i to Oracle 9i is tricky. Foremost after migrating to Oracle 9i is poor performance
from changes
to the Oracle SQL optimizer. The Oracle 9i CBO can switch to
CPU-based costing (from I/O costing in Oracle 8i) when you gather statistics
with dbms_stats.
Oracle 9i bug 2820066 is an Oracle9i migration
issue because CPU
cost is computed whenever optimizer_index_cost_adj is set to a
non-default value. Unless you have applied the 9.2.0.6 server patch set, your
Oracle 9i database may be generating CPU statistics, regardless of your CBO stats
collection method.
After an Oracle 9i migration you can turn-off CPU
costing (and re-set costing to the Oracleu8i default with this hidden parm:
_optimizer_cost_model=io;
Need Oracle 9i Migration Support?
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B.C. provides Oracle 9i Migration upgrades and Oracle 9i upgrade support for
all Oracle shops. We have Oracle 9i migration tools, Oracle 9i upgrade
training and Oracle 9i support consulting.
Call Now for Oracle 9i migration support!
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here for a list of Oracle Consulting Services


BC provides world-class Oracle 9i migration support and Oracle 9i
training and migration assistance.
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Need an Oracle Health Check?
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Note: This Oracle
documentation was created as a support and Oracle training reference for use by our
DBA performance tuning consulting professionals.
Feel free to ask questions on our
Oracle forum.
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