2.14.2019

Oracle 19c and my favorite list

Today (14-Feb-2019) Oracle officially released the 19c docs and Oracle Database 19c for Exadata through edelivery channel. Since the news is out, Oracle community is busy talking about 19c availability and sharing articles about 19c etc.

I spent a little amount of time to scan through some of really useful features of 19c for DBAs, and here is my list:
  • Availability
    • Simplified DB parameter management in Broker Configuration
    • Flashback Standby DB when Primary DB is flashed back
    • Active Data Guard DML Redirection
    • New parameter for tuning automatic outage resolution with DG
  • Data Warehousing
    • SQL Diagnostic and Repair Enhancements
    • Automatic Indexing 
    • Performance Enhancement for in-memory external tables
    • Real-Time Statistics
    • High Frequency Automatic Optimizer Statistics Collection
  • Automated install, config and patch
  • Automated upgrade, migration and utilities
  • Performance
    • SQL Quarantine 
    • Real-time monitoring for Developers
    • Workload capture and Replay in a PDB
  • RAC and Grid
    • Automated Transaction Draining for Oracle Grid Infrastructure Upgrades
    • Zero-downtime Oracle Grid Infrastructure Patching

I will start writing series of articles about my favorite Oracle 19c features. Stay tune.



References:
https://www.oracle.com/a/tech/docs/database19c-wp.pdf
https://docs.oracle.com/en/database/oracle/oracle-database/19/newft/new-features.html#GUID-06A15128-1172-48E5-8493-CD670B9E57DC
https://medium.com/oracledevs/oracle-database-19c-now-available-on-oracle-exadata-9b57963e2c89

2.04.2019

ORA-600 [ossnet_assign_msgid_1] on Exadata

On a Exadata system with Oracle v12.1, a MERGE statement with parallelism was frequently failing with below ORA errors:

                   ORA-12805: parallel query server died unexpectedly
        ORA-06512

A quick look in the alert.log, an ORA-600 is noticed.

ORA-00600: internal error code, arguments: [ossnet_assign_msgid_1], [],[ ] 

The best and easy way to diagnose any ORA-600 errors is to utilize the ORA-600 tool available on MOS.

In our case, with large hash join, the following MOS note helped to fix the issue:

On Exadata Systems large hash joins can fail with ORA-600 [OSSNET_ASSIGN_MSGID_1] (Doc ID 2254344.1)

Cause:
On Exadata Systems large hash joins can fail with ORA-600 [OSSNET_ASSIGN_MSGID_1] and the root cause if often a too small default value  for _smm_auto_min_io_size  and  _smm_auto_max_io_size'

and the workaround to fix the issue is to set the following underscore (_) parameters:

_smm_auto_max_io_size = 2048
_smm_auto_min_io_size = 256

In some cases, the below MOS notes helps to fix ORA-600 [ossnet_assign_msgid_1] error.

ORA-600 [ossnet_assign_msgid_1] (Doc ID 1522389.1)
Bug 14512766 : ORA-600 [OSSNET_ASSIGN_MSGID_1] DURING RMAN CONVERSION