Remove Underscore Parameters not only before you upgrade

Underscore parameters are a wonderful thing in Oracle. They are treated like a secret. But you can view them of course. Everybody can. Make a guess how many underscore parameters exist in Oracle 12.2.0.1.0. You’ll find the answer at the end of this blog post. But why should you remove underscore parameters not only before you upgrade? I’d like to explain below why underscores, especially too many of them, may cause a lot of trouble. Therefore, housekeeping is very important. Remove Underscore Parameters not only before you upgrade This is from a recent upgrade from Oracle 12.1.0.2 to Oracle 12.2.0.1…

Oracle 12.2 underscores appear in SPFILE – be aware when you flashback

I did blog in the past weeks about Fallback Strategies with Flashback Database. But two of my reference customers came across an interesting issue when they tried to fallback: Oracle 12.2 underscores appear in the SPFILE – magically – and prevent the fallback using the existing SPFILE. Oracle 12.2 underscores appear in SPFILE – be aware when you flashback In one case it happened during a test, in the other case it happened during a live fallback after the Data Guard Broker has interfered with the upgrade causing real trouble. In both cases the SPFILE sits in ASM. Both customers…

Obsolete SPFILE Parameters in Oracle Database 12.2.0.1

This is the 2nd posting in my series about init.ora/SPFILE parameters in Oracle Database 12.2.0.1. New SPFILE Parameters in Oracle Database 12.2.0.1 Obsolete SPFILE Parameters in Oracle Database 12.2.0.1 Deprecated SPFILE Parameters in Oracle Database 12.2.0.1 Default SPFILE Parameter changes between Oracle Database 11.2.0.4, 12.1.0.2 and 12.2.0.1 Find the list of the 159 obsoleted parameters here (and of course in V$OBSOLETE_PARAMETERS): _app_ctx_vers _average_dirties_half_life _aw_row_source_enabled _compatible_no_recovery _data_transfer_cache_size _db_no_mount_lock _dlm_send_timeout _dtree_bintest_id _dtree_compressbmp_enabled _evolve_plan_baseline_report_level _fast_start_instance_recovery_target _fic_max_length _fic_outofmem_candidates _idl_conventional_index_maintenance _kgl_latch_count _kks_free_cursor_stat_pct _kspptbl_mem_usage _lm_direct_sends _lm_multiple_receivers _lm_rcv_buffer_size _lm_statistics _log_archive_buffer_size _log_io_size _max_log_write_io_parallelism _module_action_old_length _optimizer_adaptive_plans _optimizer_choose_permutation _oracle_trace_events _oracle_trace_facility_version _plan_verify_local_time_limit _plsql_conditional_compilation _px_async_getgranule _px_slaves_share_cursors _seq_process_cache_const _spr_use_hash_table _sqlexec_progression_cost _use_hidden_partitions _very_large_partitioned_table allow_partial_sn_results…

DBUA can ignore underscores with “keepHiddenParams”

The Database Upgrade Assistant (DBUA) is the graphical tool to upgrade Oracle databases. And the DBUA removes underscore parameters by default from the SPFILE when upgrading a database. If you don’t want this, there’s a way to tell it how DBUA can ignore underscores with “keepHiddenParams”. DBUA can ignore underscores with “keepHiddenParams” The DBUA by default will remove all underscores and events before actually doing an upgrade. This is expected behaviour as we believe that underscores or events were meant to treat misbehavior of the database just in a specific release only. And in our experience a nice collection of…