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    Maxwell Miranda
    Oracle DBA Consultant.
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    • Database Replay
      Hi All, I have a question about the database replay feature. On the test system, before I begin preprocessing how do I make sure the test database = prod database before capture? Is this a full export/import or just a schema export/import? Thanks, Kathy
    • Oracle JSON parsing?
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    • Foreign Keys deferred vs disabled
      Here is my observation regarding deferred foreign keys which I am not able to understand: - We have 3 tables : TP1, TC1 & TC2. TC1 and TC2 have foreign keys pointing to TP1 and foreign keys are defined as DEFERRED. - We load huge amounts of data to these tables once a week and the insert takes unusually long time. This is how we insert: (Case 1) step 1: […]
    • Low EST_PGA_CACHE_HIT_PERCENTAGE
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    • Oracle Performance
      Hello Please I am actually using a new server on Linux Redhat with 32G (64 bits) . I need some advice to increase performance since my rman takes Now 2 hours instead of 1 hour before when I was on 16G See below pfile details Code: --------- rwddb.__db_cache_size=1577058304 rwddb.__java_pool_size=33554432 rwddb.__large_pool_size=16777216 rwddb.__shared_pool_s […]
    • New to DBA
      Hi all, Hope this is the right place to post this question. I recently joined a program that prepares students to become DBA's. Its a six month program, roughly. It's every weekend sat-sun, 4-7 P.M. I wanted to attach our course schedule and get some feedback from you guys to see if the topics covered in this course would prepare me for an actual j […]

A little additional info on hc_ files:

“Q1: What is the $ORACLE_HOME/dbs/hc_.dat file?
A1: The $ORACLE_HOME/dbs/hc_.dat is created for the instance health check monitoring. It contains information used to monitor the instance health and to determine why it went down if the instance isn’t up. The file will be recreated at every instance startup.

Q2: What happens if the $ORACLE_HOME/dbs/hc_.dat file is deleted?
A2: Per Bug 4645405 UNABLE TO START DB – ORA-7445 [KSIHSMRINI()+152] [SIGBUS],
if you replace the file with an empty “dummy” copy, you will get an ORA-7445 error. Therefore, if the file gets deleted on the fly while the database is up, or if the file is replaced with a 0 byte file, simply delete the file and restart the database. The file will be correctly recreated at the next database startup.”

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