Oracle数据库系统根据初始化参数文件init.ora中设置的参数来配置自身的启动，每个实例在启动之前，首先读取这些参数文件中设置的不同参数。Oracle系统中的参数可以简单分为两大类，普通参数，另外一类就是特殊参数，包括三种，过时参数、强调参数和隐藏参数。随着Oracle数据库新版本的发布，相应每次都会增加或者删除一些参数。如何查询当前版本数据库系统的参数情况以及当前系统版本相对于以前版本增加或者丢弃的那些参数呢？本文将详细介绍如何查询当前系统版本中的各种参数情况。

一、过时参数和强调参数   Oracle 数据库中，系统提供了几个视图可以查看系统参数的情况。视图 V$OBSOLETE_PARAMETER 中含有所有的过时 (obsolete) 和强调 (underscored) 参数。这里首先说明一下什么是 Oracle 的过时 (obsolote) 和强调 (underscored) 参数。

过时参数，顾名思义就是在 Oracle 以前的版本中存在，但在新版本中已经淘汰了的参数，已经不再使用；

强调参数，是指那些在新版本中保留了下来，但是除非特殊需要不希望用户使用的那些参数。

在视图 V$OBSOLETE_PARAMETER 中，包含这些参数的名称和一个标志字 ISSPECIFIED ，该标志字用来指出这个参数是否在 init.ora 文件中已实际设置。

SQL> col name for a50
SQL> select name ,isspecified from v$obsolete_parameter;

spin_count                                         FALSE                       
use_ism                                            FALSE                       
lock_sga_areas                                     FALSE                       
instance_nodeset                                   FALSE                       
large_pool_min_alloc                               FALSE                       
shared_pool_reserved_min_alloc                     FALSE                       
_kspptbl_mem_usage                                 FALSE                       
enqueue_resources                                  FALSE                       
lgwr_io_slaves                                     FALSE                       
arch_io_slaves                                     FALSE                       
backup_disk_io_slaves                              FALSE                       
ops_interconnects                                  FALSE                       
lm_procs                                           FALSE                       
ogms_home                                          FALSE                       
parallel_transaction_resource_timeout              FALSE                       
_lm_statistics                                     FALSE                       
lm_locks                                           FALSE                       
lm_ress                                            FALSE                       
lm_procs                                           FALSE                       
_lm_multiple_receivers                             FALSE                       
_lm_direct_sends                                   FALSE                       
_lm_rcv_buffer_size                                FALSE                       
_dlm_send_timeout                                  FALSE                       
db_block_max_dirty_target                          FALSE                       
db_block_lru_latches                               FALSE                       
db_block_checkpoint_batch                          FALSE                       
db_block_lru_statistics                            FALSE                       
db_block_lru_extended_statistics                   FALSE                       
_compatible_no_recovery                            FALSE                       
remote_archive_enable                              FALSE                       
_log_archive_buffer_size                           FALSE                       
_average_dirties_half_life                         FALSE                       
log_block_checksum                                 FALSE                       
log_small_entry_max_size                           FALSE                       
log_simultaneous_copies                            FALSE                       
log_parallelism                                    FALSE                       
db_file_simultaneous_writes                        FALSE                       
log_files                                          FALSE                       
_db_no_mount_lock                                  FALSE                       
standby_preserves_names                            FALSE                       
gc_lck_procs                                       FALSE                       
gc_releasable_locks                                FALSE                       
gc_latches                                         FALSE                       
gc_rollback_locks                                  FALSE                       
gc_defer_time                                      FALSE                       
_fast_start_instance_recovery_target               FALSE                       
freeze_DB_for_fast_instance_recovery               FALSE                       
logmnr_max_persistent_sessions                     FALSE                       
temporary_table_locks                              FALSE                       
ddl_wait_for_locks                                 FALSE                       
row_locking                                        FALSE                       
serializable                                       FALSE                       
delayed_logging_block_cleanouts                    FALSE                       
max_rollback_segments                              FALSE                       
transaction_auditing                               FALSE                       
cleanup_rollback_entries                           FALSE                       
undo_suppress_errors                               FALSE                       
discrete_transactions_enabled                      FALSE                       
sequence_cache_entries                             FALSE                       
sequence_cache_hash_buckets                        FALSE                       
_seq_process_cache_const                           FALSE                       
row_cache_cursors                                  FALSE                       
text_enable                                        FALSE                       
dblink_encrypt_login                               FALSE                       
distributed_transactions                           FALSE                       
max_transaction_branches                           FALSE                       
distributed_recovery_connection_hold_time          FALSE                       
mts_dispatchers                                    FALSE                       
mts_servers                                        FALSE                       
mts_max_servers                                    FALSE                       
mts_max_dispatchers                                FALSE                       
mts_circuits                                       FALSE                       
mts_sessions                                       FALSE                       
mts_service                                        FALSE                       
mts_listener_address                               FALSE                       
mts_multiple_listeners                             FALSE                       
plsql_compiler_flags                               FALSE                       
plsql_native_c_compiler                            FALSE                       
plsql_native_linker                                FALSE                       
plsql_native_make_utility                          FALSE                       
plsql_native_make_file_name                        FALSE                       
_plsql_conditional_compilation                     FALSE                       
job_queue_interval                                 FALSE                       
job_queue_keep_connections                         FALSE                       
snapshot_refresh_processes                         FALSE                       
snapshot_refresh_interval                          FALSE                       
snapshot_refresh_keep_connections                  FALSE                       
parallel_default_max_instances                     FALSE                       
cache_size_threshold                               FALSE                       
parallel_server_idle_time                          FALSE                       
allow_partial_sn_results                           FALSE                       
ops_admin_group                                    FALSE                       
parallel_min_message_pool                          FALSE                       
hash_join_enabled                                  FALSE                       
hash_multiblock_io_count                           FALSE                       
oracle_trace_enable                                FALSE                       
oracle_trace_facility_path                         FALSE                       
oracle_trace_collection_path                       FALSE                       
oracle_trace_facility_name                         FALSE                       
oracle_trace_collection_name                       FALSE                       
oracle_trace_collection_size                       FALSE                       
_oracle_trace_events                               FALSE                       
_oracle_trace_facility_version                     FALSE                       
close_cached_open_cursors                          FALSE                       
sort_direct_writes                                 FALSE                       
sort_write_buffers                                 FALSE                       
sort_write_buffer_size                             FALSE                       
sort_spacemap_size                                 FALSE                       
sort_read_fac                                      FALSE                       
sort_multiblock_read_count                         FALSE                       
always_anti_join                                   FALSE                       
partition_view_enabled                             FALSE                       
b_tree_bitmap_plans                                FALSE                       
complex_view_merging                               FALSE                       
push_join_predicate                                FALSE                       
fast_full_scan_enabled                             FALSE                       
parallel_broadcast_enabled                         FALSE                       
always_semi_join                                   FALSE                       
optimizer_max_permutations                         FALSE                       
optimizer_percent_parallel                         FALSE                       
optimizer_search_limit                             FALSE                       

已选择121行。可见，大部分都为false 。

       上面谈到， Oracle 系统并没有将 V$OBSOLETE_PARAMETER 视图中的所有参数均丢弃，而是将其中的一部分转换为强调参数，下面就来讨论如何查看这些参数是已被丢弃还是被转换。这可以通过系统视图 X$KSPPO 来查看，该视图中包含一个名为 KSPPOFLAG 的字段，用来指明该参数在当前版本中是被丢弃还是被强调，如果该值为 1 ，则表示该参数已被丢弃，该值为 2 ，则表明该参数现为强调参数
SQL> select kspponm,decode(ksppoflg,1,'Obsolete',2,'Underscored')
  2  from  x$ksppo
  3  order by kspponm;

_average_dirties_half_life                                       Obsolete      
_compatible_no_recovery                                          Obsolete      
_db_no_mount_lock                                                Obsolete      
_dlm_send_timeout                                                Obsolete      
_fast_start_instance_recovery_target                             Obsolete      
_kspptbl_mem_usage                                               Obsolete      
_lm_direct_sends                                                 Obsolete      
_lm_multiple_receivers                                           Obsolete      
_lm_rcv_buffer_size                                              Obsolete      
_lm_statistics                                                   Obsolete      
_log_archive_buffer_size                                         Obsolete      
_oracle_trace_events                                             Obsolete      
_oracle_trace_facility_version                                   Obsolete      
_plsql_conditional_compilation                                   Obsolete      
_seq_process_cache_const                                         Obsolete      
allow_partial_sn_results                                         Obsolete      
always_anti_join                                                 Underscored   
always_semi_join                                                 Underscored   
arch_io_slaves                                                   Underscored   
b_tree_bitmap_plans                                              Underscored   
backup_disk_io_slaves                                            Underscored   
cache_size_threshold                                             Obsolete      
cleanup_rollback_entries                                         Underscored   
close_cached_open_cursors                                        Underscored   
complex_view_merging                                             Underscored   
db_block_checkpoint_batch                                        Obsolete      
db_block_lru_extended_statistics                                 Obsolete      
db_block_lru_latches                                             Underscored   
db_block_lru_statistics                                          Obsolete      
db_block_max_dirty_target                                        Obsolete      
db_file_simultaneous_writes                                      Obsolete      
dblink_encrypt_login                                             Obsolete      
ddl_wait_for_locks                                               Obsolete      
delayed_logging_block_cleanouts                                  Obsolete      
discrete_transactions_enabled                                    Underscored   
distributed_recovery_connection_hold_time                        Underscored   
distributed_transactions                                         Obsolete      
enqueue_resources                                                Underscored   
fast_full_scan_enabled                                           Underscored   
freeze_DB_for_fast_instance_recovery                             Obsolete      
gc_defer_time                                                    Underscored   
gc_latches                                                       Underscored   
gc_lck_procs                                                     Obsolete      
gc_releasable_locks                                              Obsolete      
gc_rollback_locks                                                Obsolete      
hash_join_enabled                                                Underscored   
hash_multiblock_io_count                                         Underscored   
instance_nodeset                                                 Obsolete      
job_queue_interval                                               Obsolete      
job_queue_keep_connections                                       Obsolete      
large_pool_min_alloc                                             Underscored   
lgwr_io_slaves                                                   Underscored   
lm_locks                                                         Underscored   
lm_procs                                                         Underscored   
lm_procs                                                         Underscored   
lm_ress                                                          Underscored   
lock_sga_areas                                                   Underscored   
log_block_checksum                                               Obsolete      
log_files                                                        Obsolete      
log_parallelism                                                  Obsolete      
log_simultaneous_copies                                          Underscored   
log_small_entry_max_size                                         Obsolete      
logmnr_max_persistent_sessions                                   Obsolete      
max_rollback_segments                                            Obsolete      
max_transaction_branches                                         Obsolete      
mts_circuits                                                     Obsolete      
mts_dispatchers                                                  Obsolete      
mts_listener_address                                             Obsolete      
mts_max_dispatchers                                              Obsolete      
mts_max_servers                                                  Obsolete      
mts_multiple_listeners                                           Obsolete      
mts_servers                                                      Obsolete      
mts_service                                                      Obsolete      
mts_sessions                                                     Obsolete      
ogms_home                                                        Underscored   
ops_admin_group                                                  Obsolete      
ops_interconnects                                                Obsolete      
optimizer_max_permutations                                       Underscored   
optimizer_percent_parallel                                       Underscored   
optimizer_search_limit                                           Underscored   
oracle_trace_collection_name                                     Obsolete      
oracle_trace_collection_path                                     Obsolete      
oracle_trace_collection_size                                     Obsolete      
oracle_trace_enable                                              Obsolete      
oracle_trace_facility_name                                       Obsolete      
oracle_trace_facility_path                                       Obsolete      
parallel_broadcast_enabled                                       Underscored   
parallel_default_max_instances                                   Underscored   
parallel_min_message_pool                                        Underscored   
parallel_server_idle_time                                        Underscored   
parallel_transaction_resource_timeout                            Obsolete      
partition_view_enabled                                           Underscored   
plsql_compiler_flags                                             Obsolete      
plsql_native_c_compiler                                          Obsolete      
plsql_native_linker                                              Obsolete      
plsql_native_make_file_name                                      Obsolete      
plsql_native_make_utility                                        Obsolete      
push_join_predicate                                              Underscored   
remote_archive_enable                                            Obsolete      
row_cache_cursors                                                Underscored   
row_locking                                                      Underscored   
sequence_cache_entries                                           Obsolete      
sequence_cache_hash_buckets                                      Obsolete      
serializable                                                     Underscored   
shared_pool_reserved_min_alloc                                   Underscored   
snapshot_refresh_interval                                        Obsolete      
snapshot_refresh_keep_connections                                Obsolete      
snapshot_refresh_processes                                       Obsolete      
sort_direct_writes                                               Obsolete      
sort_multiblock_read_count                                       Underscored   
sort_read_fac                                                    Obsolete      
sort_spacemap_size                                               Obsolete      
sort_write_buffer_size                                           Obsolete      
sort_write_buffers                                               Obsolete      
spin_count                                                       Underscored   
standby_preserves_names                                          Obsolete      
temporary_table_locks                                            Obsolete      
text_enable                                                      Obsolete      
transaction_auditing                                             Underscored   
undo_suppress_errors                                             Obsolete      
use_ism                                                          Underscored   

已选择121行。

SQL> select decode(ksppoflg,1,'Obsolete',2,'Underscored'),count(ksppoflg)
  2  from  x$ksppo
  3  group by ksppoflg;

Obsolete                     78       --78个参数已被丢弃                                             
Underscored              43       --43个参数现为强调参数
                                             
限于篇幅，在下一篇继续。。