Query statements commonly used in Oracle
SELECT * from user_views where view_name='v$session';
SELECT * FROM ALL_USERS where username like 'S%';
select * from v$database;
select username,profile from dba_users;;
select * from dba_profiles where profile='DEFAULT';
SELECT * from v$archive_dest;
select * from v$kccle;
select * from v$logfile;
select * from v$archive_dest;
select * from v$archive_dest_status;
select * from dba_tables T where owner='SYSTEM' AND TABLE_NAME LIKE 'FAM%';
analyze table family compute statistics for table--table analysis;
select * from user_tables where table_name='FAMILY';
select * from v$parameter where name='db_block_size';
select segment_name,bytes from user_segments;
select count(*) from all_tables;
select count(*) from dba_tables;
select * from dba_tables where tablespace_name='SYSTEM' and table_name='FAMILY';
select segment_name,count(*),round(sum(bytes/1024/1024)，9） MB from user_segments group by segment_name order by MB desc;
select * from REPCAT$_DDL;
select * from user_segments wheRE segment_name='REPCAT$_DDL';
select count(*) from user_tables;
select * from DBA_tables WHERE TABLE_NAME='SYSTEM';
SELECT SUM(BYTES/1024/1024) FROM DBA_EXTENTS WHERE SEGMENT_NAME='FAMILY';
SELECT SUM(BYTES/1024/1024) FROM DBA_DATA_FILES WHERE TABLESPACE_NAME='SYSTEM';
SELECT SUM(BYTES/1024/1024) FROM DBA_FREE_SPACE WHERE TABLESPACE_NAME='SYSTEM';
SELECT SEGMENT_NAME,sum(bytes/1024/1024) from user_segments group by segment_name having segment_name='FAMILY';
SELECT SUM(BYTES/1024/1024) FROM DBA_EXTENTS WHERE SEGMENT_NAME='FAMILY';
SELECT SUM(BYTES/1024/1024) FROM USER_SEGMENTS WHERE SEGMENT_NAME='FAMILY';
SELECT 1-104.5625/810 FROM DUAL;
/*select a.tablespace_name,a.bytes/1024/1024 "sum MB",(a.bytes-b.bytes)/1024/1024 "used MB",b.bytes/1024/1024 "free MB",round(((a.bytes-b.bytes)/a.bytes)*100,2) "percent_used"
from
(select tablespace_name,sum(bytes) bytes from dba_data_files group by tablespace_name) a,
(select tablespace_name,sum(bytes) bytes,max(bytes) largest from dba_free_space group by tablespace_name) b
where a.tablespace_name=b.tablespace_name
order by ((a.bytes-b.bytes)/a.bytes) desc
--Tablespace */
select SUM(BYTES/1024/1024) from SYS.DBA_FREE_SPACE t WHERE TABLESPACE_NAME='SYSTEM';
SELECT TABLESPACE_NAME,SUM(BYTES/1024/1024) MB FROM DBA_DATA_FILES GROUP BY TABLESPACE_NAME;
SELECT SUM(BYTES/1024/1024) MB FROM DBA_DATA_FILES WHERE TABLESPACE_NAME='SYSTEM';
select * from SYS.DBA_FREE_SPACE t;
SELECT * FROM DBA_EXTENTS WHERE SEGMENT_NAME='FAMILY';
SELECT SUM(BYTES/1024/1024) MB FROM DBA_EXTENTS WHERE SEGMENT_NAME ='FAMILY ' ;--Size of table;
SELECT BYTES/1024/1024 FROM DBA_SEGMENTS WHERE SEGMENT_NAME ='FAMILY ';--Size of table
select * from v$parameter where name ='db_block_size';--Block size
select blocks*8/1024 from user_tables where table_name ='FAMILY ';--Size of table
select sql_text,first_load_time from v$sql order by first_load_time desc;
commit;
select * from family;
delete from family where name='zXq';
alter system switch logfile;--redo log switch, archive log will switch after switch
select * from v$logfile; --redo log
select * from v$archive_dest;--archive logs-
select * from v$parameter where name ='db_recovery_file_dest_size';--Total archive log size-
select * from v$parameter where name like '%retention_target';
select * from v$parameter where name='db_recovery_file_dest';
select * from v$flashback_database_log;
select flashback_on from v$database;--Check if database flashback is enabled
select * from v$version;--Database version
select * from v$parameter where name like '%retention_target';
select value/1024/1024/1024 AS "LOG/GB" from v$parameter where name='db_recovery_file_dest_size'--3.76171875;
select * from v$parameter where name='db_recovery_file_dest';
select to_char(sysdate,'yyyy-mm-dd hh34:mi:ss') from dual;;
select * from user_recyclbin;--Recycle bin
select * from v$parameter where name ='background_dump_dest';--Warning files and system trace file locations
select * from v$parameter where name ='user_dump_dest';--user tracking file location
