Query Oracle for slow session and SQL

--Query for the slowest SQL

SELECT * FROM (
Select Parsing_user_id,executions,sorts
Command_type,disk_reads,sql_text from V$sqlarea ORDER BY disk_reads Desc
) Where rownum<10

--Query corresponding session

Select SE. Sid,se. Serial#,pr. SPID,
SE. Username,se. Status,se. TERMINAL,
SE. Program,se. MODULE,
SE. Sql_address,st. EVENT,
St. P1text,si. Physical_reads,si. Block_changes from V$session Se,v$session_wait St,
V$sess_io si,v$process PR
Where St. Sid=se. SID and St. Sid=si. Sid
and SE. Paddr=pr. ADDR
and SE. Sid>6
and ST. Wait_time=0
and ST. EVENT not like '%sql% '
ORDER by Physical_reads DESC;
SELECT sql_address from V$session ss,v$sqltext TT
WHERE SS. Sql_hash_value=tt. Hash_value and sid=439;

V$sqltext: The stored full sql,sql is split

V$sqlarea: Stored SQL and some related information, such as the cumulative number of executions, logical reading, physical reading and other statistical information (statistics)

V$sql: A SQL statement that has been resolved in a memory-shared SQL zone. Instant

To find the full SQL statement based on the SID:

Select Sql_text from V$sqltext a WHERE A.hash_value = (select Sql_hash_value from v$session b where b.sid = ' &sid ' )
ORDER BY piece ASC

Select A.cpu_time,--CPU time one out of 10,000 (microseconds)
A.optimizer_mode,--Optimization method
A.executions,--Execution times
A.disk_reads,--Read Disk count
A.sharable_mem,--The amount of memory occupied by the shared pool
A.buffer_gets,--The number of read buffers
A.command_type,--Command Type (3:select,2:insert;6:update;7delete;47:pl/sql program unit)
A.sql_text,--SQL Statements
A.sharable_mem,
A.persistent_mem,
A.runtime_mem,
A.parse_calls,
A.disk_reads,
A.direct_writes,
A.concurrency_wait_time,
A.user_io_wait_time
From SYS. V_$sqlarea A
WHERE parsing_schema_name = ' chea_fill '--table space
ORDER BY a.cpu_time Desc

Reference: http://jenniferok.iteye.com/blog/700985

Query the most resource-intensive query from V$sqlarea Select B.username username,a.disk_reads reads,
A.executions Exec,a.disk_reads/decode (a.executions,0,1,a.executions) Rds_exec_ratio,
A.sql_text Statement
From V$sqlarea A,dba_users b
where a.parsing_user_id=b.user_id
and A.disk_reads > 100000
ORDER BY a.disk_reads Desc; Replacing the disk_reads column with the buffer_gets column gives you information about the SQL statement that consumes the most memory. V$sql: A SQL statement that has been resolved in a memory-shared SQL zone. Instant
List the 5 most frequently used queries: select Sql_text,executions
From (select Sql_text,executions,
Rank () over
(Order BY executions Desc) Exec_rank
From V$sql)
Where Exec_rank <=5; consumes disk reads the most SQL TOP5:
Select Disk_reads,sql_text
From (select Sql_text,disk_reads,
Dense_rank () over
(Order BY disk_reads Desc) Disk_reads_rank
From V$sql)
where Disk_reads_rank <=5;
Find queries that require a large buffer read (logical read) operation: Select Buffer_gets,sql_text
From (select Sql_text,buffer_gets,
Dense_rank () over
(Order BY buffer_gets Desc) Buffer_gets_rank
From V$sql)
where buffer_gets_rank<=5; V$sqlarea Field Definition: http://happyhou.blog.sohu.com/60494432.html

SQL_TEXT	VARCHAR2(1000)	The first 1000 characters of a SQL literal
SQL_ID	VARCHAR2(13)	SQL identifier of the parent cursor in the library cache
SHARABLE_MEM	NUMBER	Shared memory size (in bytes)
PERSISTENT_MEM	NUMBER	Fixed memory size (in bytes) for the lifetime
RUNTIME_MEM	NUMBER	Fixed memory size during the execution period
SORTS	NUMBER	Number of orders completed
VERSION_COUNT	NUMBER	Number of child cursors that is present in the cache under this parent
LOADED_VERSIONS	NUMBER	Shows whether the context heap is loaded, 1 is 0 no
OPEN_VERSIONS	NUMBER	Shows if the child cursor is locked, 1 is 0 no
USERS_OPENING	NUMBER	Number of users executing the statement
FETCHES	NUMBER	The number of fetch for the SQL statement.
EXECUTIONS	NUMBER	Number of executions since it was loaded into the cache library
END_OF_FETCH_COUNT	NUMBER	Number of times this cursor is fully executed since the cursor is brought into the library cache. The value of this statistic isn't incremented when the cursor is partially executed, either because it failed during the Execution or because only the first few rows produced by this cursor be fetched before the cursor is closed or re-execute D. By definition, the value of the END_OF_FETCH_COUNT column should is less or equal to the value of the EXECUTIONS column.
USERS_EXECUTING	NUMBER	Number of users executing the statement
LOADS	NUMBER	Number of times the object has been loaded
FIRST_LOAD_TIME	VARCHAR2(19)	Initial loading time
INVALIDATIONS	NUMBER	Invalid number of times
PARSE_CALLS	NUMBER	Number of calls resolved
DISK_READS	NUMBER	Number of Read disks
DIRECT_WRITES	NUMBER	Sum of the number of direct writes over all child cursors
BUFFER_GETS	NUMBER	Number of Read buffers
APPLICATION_WAIT_TIME	NUMBER	Application Wait Time
CONCURRENCY_WAIT_TIME	NUMBER	Concurrency Wait Time
CLUSTER_WAIT_TIME	NUMBER	Cluster Wait Time
USER_IO_WAIT_TIME	NUMBER	User I/O Wait time
PLSQL_EXEC_TIME	NUMBER	PL/SQL Execution time
JAVA_EXEC_TIME	NUMBER	Java Execution Time
ROWS_PROCESSED	NUMBER	The total number of columns returned by the parse SQL statement
COMMAND_TYPE	NUMBER	Command Type Code
OPTIMIZER_MODE	VARCHAR2(25)	The optimizer model of the QL statement
PARSING_USER_ID	NUMBER	The first resolved user ID
PARSING_SCHEMA_ID	NUMBER	The first resolved plan ID
KEPT_VERSIONS	NUMBER	Indicates whether the current child cursor is marked as resident memory using the Dbms_shared_pool package
ADDRESS	RAW(4 | 8)	Current cursor Parent handle address
HASH_VALUE	NUMBER	Hash value of the parent statement in the library cache
OLD_HASH_VALUE	NUMBER	Old SQL Hash value
MODULE	VARCHAR2(64)	Contains the name of the module is executing at the time that the SQL statement is first parsed as set by calling c6/>.SET_MODULE
MODULE_HASH	NUMBER	Hash value of the module is named in the MODULE column
ACTION	VARCHAR2(64)	Contains the name of the action is executing at the time that the SQL statement is first parsed as set by calling c2/>.SET_ACTION
ACTION_HASH	NUMBER	Hash value of the action that's named in the ACTION column
SERIALIZABLE_ABORTS	NUMBER	Number of times the transaction fails to serialize, producing ORA-08177 errors, totalled through all the child cursors
CPU_TIME	NUMBER	CPU time (in microseconds) used by the cursor for parsing/executing/fetching
ELAPSED_TIME	NUMBER	Elapsed time (in microseconds) used by the cursor for parsing/executing/fetching
IS_OBSOLETE	VARCHAR2(1)	Indicates whether the cursor has a become obsolete ( Y ) or not ( N ). This can happen if the number of child cursors is too large.
CHILD_LATCH	NUMBER	Child latch number which is protecting the cursor
PROGRAM_ID	NUMBER	Program Identifie

Source: http://blog.csdn.net/sxhong/article/details/18262663

Query Oracle for slow session and SQL