v$sql,v$sqlarea,v$sqltext 和 v$sql_plan 说明

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tianlesoftware 2022-09-01 22:30:59 ©著作权

文章标签 sql documentation library oracle statistics 文章分类 虚拟化云计算

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一. 先看官网对这几个视图的说明（ORACLE 11gR2）

1.1 V$SQL

V$SQL lists statistics on shared SQL areas without the GROUP BY clause and contains one row for each child of the original SQL text entered. Statistics displayed in V$SQL are normally updated at the end of query execution. However, for long running queries, they are updated every 5 seconds. This makes it easy to see the impact of long running SQL statements while they are still in progress.

Column	Datatype	Description
`SQL_TEXT`	`VARCHAR2(1000)`	First thousand characters of the SQL text for the current cursor
`SQL_FULLTEXT`	`CLOB`	Full text for the SQL statement exposed as a `CLOB` column. The full text of a SQL statement can be retrieved using this column instead of joining with the `V$SQLTEXT` dynamic performance view.
`SQL_ID`	`VARCHAR2(13)`	SQL identifier of the parent cursor in the library cache
`SHARABLE_MEM`	`NUMBER`	Amount of shared memory used by the child cursor (in bytes)
`PERSISTENT_MEM`	`NUMBER`	Fixed amount of memory used for the lifetime of the child cursor (in bytes)
`RUNTIME_MEM`	`NUMBER`	Fixed amount of memory required during the execution of the child cursor
`SORTS`	`NUMBER`	Number of sorts that were done for the child cursor
`LOADED_VERSIONS`	`NUMBER`	Indicates whether the context heap is loaded (`1`) or not (`0`)
`OPEN_VERSIONS`	`NUMBER`	Indicates whether the child cursor is locked (`1`) or not (`0`)
`USERS_OPENING`	`NUMBER`	Number of users executing the statement
`FETCHES`	`NUMBER`	Number of fetches associated with the SQL statement
`EXECUTIONS`	`NUMBER`	Number of executions that took place on this object since it was brought into the library cache
`PX_SERVERS_EXECUTIONS`	`NUMBER`	Total number of executions performed by parallel execution servers (`0` when the statement has never been executed in parallel)
`END_OF_FETCH_COUNT`	`NUMBER`	Number of times this cursor was fully executed since the cursor was brought into the library cache. The value of this statistic is not 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 are fetched before the cursor is closed or re-executed. By definition, the value of the `END_OF_FETCH_COUNT` column should be 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 was either loaded or reloaded
`FIRST_LOAD_TIME`	`VARCHAR2(19)`	Timestamp of the parent creation time
`INVALIDATIONS`	`NUMBER`	Number of times this child cursor has been invalidated
`PARSE_CALLS`	`NUMBER`	Number of parse calls for this child cursor
`DISK_READS`	`NUMBER`	Number of disk reads for this child cursor
`DIRECT_WRITES`	`NUMBER`	Number of direct writes for this child cursor
`BUFFER_GETS`	`NUMBER`	Number of buffer gets for this child cursor
`APPLICATION_WAIT_TIME`	`NUMBER`	Application wait time (in microseconds)
`CONCURRENCY_WAIT_TIME`	`NUMBER`	Concurrency wait time (in microseconds)
`CLUSTER_WAIT_TIME`	`NUMBER`	Cluster wait time (in microseconds)
`USER_IO_WAIT_TIME`	`NUMBER`	User I/O Wait Time (in microseconds)
`PLSQL_EXEC_TIME`	`NUMBER`	PL/SQL execution time (in microseconds)
`JAVA_EXEC_TIME`	`NUMBER`	Java execution time (in microseconds)
`ROWS_PROCESSED`	`NUMBER`	Total number of rows the parsed SQL statement returns
`COMMAND_TYPE`	`NUMBER`	Oracle command type definition
`OPTIMIZER_MODE`	`VARCHAR2(10)`	Mode under which the SQL statement was executed
`OPTIMIZER_COST`	`NUMBER`	Cost of this query given by the optimizer
`OPTIMIZER_ENV`	`RAW(2000)`	Optimizer environment
`OPTIMIZER_ENV_HASH_VALUE`	`NUMBER`	Hash value for the optimizer environment
`PARSING_USER_ID`	`NUMBER`	User ID of the user who originally built this child cursor
`PARSING_SCHEMA_ID`	`NUMBER`	Schema ID that was used to originally build this child cursor
`PARSING_SCHEMA_NAME`	`VARCHAR2(30)`	Schema name that was used to originally build this child cursor
`KEPT_VERSIONS`	`NUMBER`	Indicates whether this child cursor has been marked to be kept pinned in the cache using the `DBMS_SHARED_POOL` package
`ADDRESS`	`RAW(4 \| 8)`	Address of the handle to the parent for this cursor
`TYPE_CHK_HEAP`	`RAW(4)`	Descriptor of the type check heap for this child cursor
`HASH_VALUE`	`NUMBER`	Hash value of the parent statement in the library cache
`OLD_HASH_VALUE`	`NUMBER`	Old SQL hash value
`PLAN_HASH_VALUE`	`NUMBER`	Numeric representation of the SQL plan for this cursor. Comparing one `PLAN_HASH_VALUE` to another easily identifies whether or not two plans are the same (rather than comparing the two plans line by line).
`CHILD_NUMBER`	`NUMBER`	Number of this child cursor
`SERVICE`	`VARCHAR2(64)`	Service name
`SERVICE_HASH`	`NUMBER`	Hash value for the name listed in the `SERVICE`column
`MODULE`	`VARCHAR2(64)`	Contains the name of the module that was executing at the time that the SQL statement was first parsed, which is set by calling `DBMS_APPLICATION_INFO.SET_MODULE`
`MODULE_HASH`	`NUMBER`	Hash value of the module listed in the `MODULE` column
`ACTION`	`VARCHAR2(64)`	Contains the name of the action that was executing at the time that the SQL statement was first parsed, which is set by calling `DBMS_APPLICATION_INFO.SET_ACTION`
`ACTION_HASH`	`NUMBER`	Hash value of the action listed in the `ACTION` column
`SERIALIZABLE_ABORTS`	`NUMBER`	Number of times the transaction failed to serialize, producing `ORA-08177` errors, per cursor
`OUTLINE_CATEGORY`	`VARCHAR2(64)`	If an outline was applied during construction of the cursor, then this column displays the category of that outline. Otherwise the column is left blank.
`CPU_TIME`	`NUMBER`	CPU time (in microseconds) used by this cursor for parsing, executing, and fetching
`ELAPSED_TIME`	`NUMBER`	Elapsed time (in microseconds) used by this cursor for parsing, executing, and fetching
`OUTLINE_SID`	`NUMBER`	Outline session identifier
`CHILD_ADDRESS`	`RAW(4 \| 8)`	Address of the child cursor
`SQLTYPE`	`NUMBER`	Denotes the version of the SQL language used for this statement
`REMOTE`	`VARCHAR2(1)`	Indicates whether the cursor is remote mapped (`Y`) or not (`N`)
`OBJECT_STATUS`	`VARCHAR2(19)`	Status of the cursor: · `VALID` - Valid, authorized without errors · `VALID_AUTH_ERROR` - Valid, authorized with authorization errors · `VALID_COMPILE_ERROR` - Valid, authorized with compilation errors · `VALID_UNAUTH` - Valid, unauthorized · `INVALID_UNAUTH` - Invalid, unauthorized · `INVALID` - Invalid, unauthorized but keep the timestamp
`LITERAL_HASH_VALUE`	`NUMBER`	Hash value of the literals which are replaced with system-generated bind variables and are to be matched, when `CURSOR_SHARING` is used. This is not the hash value for the SQL statement. If `CURSOR_SHARING` is not used, then the value is `0`.
`LAST_LOAD_TIME`	`VARCHAR2(19)`	Time at which the query plan was loaded into the library cache
`IS_OBSOLETE`	`VARCHAR2(1)`	Indicates whether the cursor has become obsolete (`Y`) or not (`N`). This can happen if the number of child cursors is too large.
`IS_BIND_SENSITIVE`	`VARCHAR2(1)`	Indicates whether the cursor is bind sensitive (`Y`) or not (`N`). A query is considered bind-sensitive if the optimizer peeked at one of its bind variable values when computing predicate selectivities and where a change in a bind variable value may cause the optimizer to generate a different plan.
`IS_BIND_AWARE`	`VARCHAR2(1)`	Indicates whether the cursor is bind aware (`Y`) or not (`N`). A query is considered bind-aware if it has been marked to use extended cursor sharing. The query would already have been marked as bind-sensitive.
`IS_SHAREABLE`	`VARCHAR2(1)`	Indicates whether the cursor can be shared (`Y`) or not (`N`)
`CHILD_LATCH`	`NUMBER`	Child latch number that is protecting the cursor. This column is obsolete and maintained for backward compatibility.
`SQL_PROFILE`	`VARCHAR2(64)`	SQL profile used for this statement, if any
`SQL_PATCH`	`VARCHAR2(30)`	SQL patch used for this statement, if any
`SQL_PLAN_BASELINE`	`VARCHAR2(30)`	SQL plan baseline used for this statement, if any
`PROGRAM_ID`	`NUMBER`	Program identifier
`PROGRAM_LINE#`	`NUMBER`	Program line number
`EXACT_MATCHING_SIGNATURE`	`NUMBER`	Signature calculated on the normalized SQL text. The normalization includes the removal of white space and the uppercasing of all non-literal strings.
`FORCE_MATCHING_SIGNATURE`	`NUMBER`	Signature used when the `CURSOR_SHARING` parameter is set to `FORCE`
`LAST_ACTIVE_TIME`	`DATE`	TIme at which the query plan was last active
`BIND_DATA`	`RAW(2000)`	Bind data
`TYPECHECK_MEM`	`NUMBER`	Typecheck memory
`IO_CELL_OFFLOAD_ELIGIBLE_BYTES`	`NUMBER`	Number of I/O bytes which can be filtered by the Exadata storage system See Also: Oracle Exadata Storage Server Software documentation for more information
`IO_INTERCONNECT_BYTES`	`NUMBER`	Number of I/O bytes exchanged between Oracle Database and the storage system
`PHYSICAL_READ_REQUESTS`	`NUMBER`	Number of physical read I/O requests issued by the monitored SQL
`PHYSICAL_READ_BYTES`	`NUMBER`	Number of bytes read from disks by the monitored SQL
`PHYSICAL_WRITE_REQUESTS`	`NUMBER`	Number of physical write I/O requests issued by the monitored SQL
`PHYSICAL_WRITE_BYTES`	`NUMBER`	Number of bytes written to disks by the monitored SQL
`OPTIMIZED_PHY_READ_REQUESTS`	`NUMBER`	Number of physical read I/O requests from Database Smart Flash Cache issued by the monitored SQL
`LOCKED_TOTAL`	`NUMBER`	Total number of times the child cursor has been locked
`PINNED_TOTAL`	`NUMBER`	Total number of times the child cursor has been pinned
`IO_CELL_UNCOMPRESSED_BYTES`	`NUMBER`	Number of uncompressed bytes (that is, size after decompression) that are offloaded to the Exadata cells See Also: Oracle Exadata Storage Server Software documentation for more information
`IO_CELL_OFFLOAD_RETURNED_BYTES`	`NUMBER`	Number of bytes that are returned by the Exadata cell for smart scan only (that is, not including bytes for other database I/O) See Also: Oracle Exadata Storage Server Software documentation for more information

1.2 V$SQLAREA

V$SQLAREA displays statistics on shared SQL areas and contains one row per SQL string. It provides statistics on SQL statements that are in memory, parsed, and ready for execution.

Column	Datatype	Description
`SQL_TEXT`	`VARCHAR2(1000)`	First thousand characters of the SQL text for the current cursor
`SQL_FULLTEXT`	`CLOB`	All characters of the SQL text for the current cursor
`SQL_ID`	`VARCHAR2(13)`	SQL identifier of the parent cursor in the library cache
`SHARABLE_MEM`	`NUMBER`	Amount of shared memory used by a cursor. If multiple child cursors exist, then the sum of all shared memory used by all child cursors.
`PERSISTENT_MEM`	`NUMBER`	Fixed amount of memory used for the lifetime of an open cursor. If multiple child cursors exist, then the fixed sum of memory used for the lifetime of all the child cursors.
`RUNTIME_MEM`	`NUMBER`	Fixed amount of memory required during execution of a cursor. If multiple child cursors exist, then the fixed sum of all memory required during execution of all the child cursors.
`SORTS`	`NUMBER`	Sum of the number of sorts that were done for all the child cursors
`VERSION_COUNT`	`NUMBER`	Number of child cursors that are present in the cache under this parent
`LOADED_VERSIONS`	`NUMBER`	Number of child cursors that are present in the cache and have their context heap loaded
`OPEN_VERSIONS`	`NUMBER`	Number of child cursors that are currently open under this current parent
`USERS_OPENING`	`NUMBER`	Number of users that have any of the child cursors open
`FETCHES`	`NUMBER`	Number of fetches associated with the SQL statement
`EXECUTIONS`	`NUMBER`	Total number of executions, totalled over all the child cursors
`PX_SERVERS_EXECUTIONS`	`NUMBER`	Total number of executions performed by parallel execution servers (`0` when the statement has never been executed in parallel)
`END_OF_FETCH_COUNT`	`NUMBER`	Number of times this cursor was fully executed since the cursor was brought into the library cache. The value of this statistic is not 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 are fetched before the cursor is closed or re-executed. By definition, the value of the `END_OF_FETCH_COUNT` column should be less or equal to the value of the `EXECUTIONS` column.
`USERS_EXECUTING`	`NUMBER`	Total number of users executing the statement over all child cursors
`LOADS`	`NUMBER`	Number of times the object was loaded or reloaded
`FIRST_LOAD_TIME`	`VARCHAR2(19)`	Timestamp of the parent creation time
`INVALIDATIONS`	`NUMBER`	Total number of invalidations over all the child cursors
`PARSE_CALLS`	`NUMBER`	Sum of all parse calls to all the child cursors under this parent
`DISK_READS`	`NUMBER`	Sum of the number of disk reads over all child cursors
`DIRECT_WRITES`	`NUMBER`	Sum of the number of direct writes over all child cursors
`BUFFER_GETS`	`NUMBER`	Sum of buffer gets over all child cursors
`APPLICATION_WAIT_TIME`	`NUMBER`	Application wait time (in microseconds)
`CONCURRENCY_WAIT_TIME`	`NUMBER`	Concurrency wait time (in microseconds)
`CLUSTER_WAIT_TIME`	`NUMBER`	Cluster wait time (in microseconds)
`USER_IO_WAIT_TIME`	`NUMBER`	User I/O Wait Time (in microseconds)
`PLSQL_EXEC_TIME`	`NUMBER`	PL/SQL execution time (in microseconds)
`JAVA_EXEC_TIME`	`NUMBER`	Java execution time (in microseconds)
`ROWS_PROCESSED`	`NUMBER`	Total number of rows processed on behalf of this SQL statement
`COMMAND_TYPE`	`NUMBER`	Oracle command type definition
`OPTIMIZER_MODE`	`VARCHAR2(10)`	Mode under which the SQL statement was executed
`OPTIMIZER_COST`	`NUMBER`	Cost of this query given by the optimizer
`OPTIMIZER_ENV`	`RAW(2000)`	Optimizer environment
`OPTIMIZER_ENV_HASH_VALUE`	`NUMBER`	Hash value for the optimizer environment
`PARSING_USER_ID`	`NUMBER`	User ID of the user that has parsed the very first cursor under this parent
`PARSING_SCHEMA_ID`	`NUMBER`	Schema ID that was used to parse this child cursor
`PARSING_SCHEMA_NAME`	`VARCHAR2(30)`	Schema name that was used to parse this child cursor
`KEPT_VERSIONS`	`NUMBER`	Number of child cursors that have been marked to be kept using the `DBMS_SHARED_POOL` package
`ADDRESS`	`RAW(4 \| 8)`	Address of the handle to the parent for this cursor
`HASH_VALUE`	`NUMBER`	Hash value of the parent statement in the library cache
`OLD_HASH_VALUE`	`NUMBER`	Old SQL hash value
`PLAN_HASH_VALUE`	`NUMBER`	Numeric representation of the SQL plan for this cursor. Comparing one `PLAN_HASH_VALUE` to another easily identifies whether or not two plans are the same (rather than comparing the two plans line by line).
`MODULE`	`VARCHAR2(64)`	Contains the name of the module that was executing at the time that the SQL statement was first parsed as set by calling `DBMS_APPLICATION_INFO.SET_MODULE`
`MODULE_HASH`	`NUMBER`	Hash value of the module that is named in the `MODULE` column
`ACTION`	`VARCHAR2(64)`	Contains the name of the action that was executing at the time that the SQL statement was first parsed as set by calling `DBMS_APPLICATION_INFO.SET_ACTION`
`ACTION_HASH`	`NUMBER`	Hash value of the action that is named in the `ACTION` column
`SERIALIZABLE_ABORTS`	`NUMBER`	Number of times the transaction failed to serialize, producing `ORA-08177` errors, totalled over all the child cursors
`OUTLINE_CATEGORY`	`VARCHAR2(64)`	If an outline was applied during construction of the cursor, then this column displays the category of that outline. Otherwise the column is left blank.
`CPU_TIME`	`NUMBER`	CPU time (in microseconds) used by this cursor for parsing, executing, and fetching
`ELAPSED_TIME`	`NUMBER`	Elapsed time (in microseconds) used by this cursor for parsing, executing, and fetching
`OUTLINE_SID`	`VARCHAR2(40)`	Outline session identifier
`LAST_ACTIVE_CHILD_ADDRESS`	`RAW(4 \| 8)`	Address (identifier) of the child cursor that was the last to be active in the group (that is, the child cursor on behalf of which statistics in `V$SQL` were updated)
`REMOTE`	`VARCHAR2(1)`	Indicates whether the cursor is remote mapped (`Y`) or not (`N`)
`OBJECT_STATUS`	`VARCHAR2(19)`	Status of the cursor: · `VALID` - Valid, authorized without errors · `VALID_AUTH_ERROR` - Valid, authorized with authorization errors · `VALID_COMPILE_ERROR` - Valid, authorized with compilation errors · `VALID_UNAUTH` - Valid, unauthorized · `INVALID_UNAUTH` - Invalid, unauthorized · `INVALID` - Invalid, unauthorized but keep the timestamp
`LITERAL_HASH_VALUE`	`NUMBER`	Hash value of the literals which are replaced with system-generated bind variables and are to be matched, when `CURSOR_SHARING` is used. This is not the hash value for the SQL statement. If `CURSOR_SHARING` is not used, then the value is `0`.
`LAST_LOAD_TIME`	`DATE`	Time at which the query plan was loaded into the library cache
`IS_OBSOLETE`	`VARCHAR2(1)`	Indicates whether the cursor has become obsolete (`Y`) or not (`N`). This can happen if the number of child cursors is too large.
`IS_BIND_SENSITIVE`	`VARCHAR2(1)`	Indicates whether the cursor is bind sensitive (`Y`) or not (`N`). A query is considered bind-sensitive if the optimizer peeked at one of its bind variable values when computing predicate selectivities and where a change in a bind variable value may cause the optimizer to generate a different plan.
`IS_BIND_AWARE`	`VARCHAR2(1)`	Indicates whether the cursor is bind aware (`Y`) or not (`N`). A query is considered bind-aware if it has been marked to use extended cursor sharing. The query would already have been marked as bind-sensitive.
`CHILD_LATCH`	`NUMBER`	Child latch number that is protecting the cursor. This column is obsolete and maintained for backward compatibility.
`SQL_PROFILE`	`VARCHAR2(64)`	SQL profile used for this statement, if any
`SQL_PATCH`	`VARCHAR2(30)`	SQL patch used for this statement, if any
`SQL_PLAN_BASELINE`	`VARCHAR2(30)`	SQL plan baseline used for this statement, if any
`PROGRAM_ID`	`NUMBER`	Program identifier
`PROGRAM_LINE#`	`NUMBER`	Program line number
`EXACT_MATCHING_SIGNATURE`	`NUMBER`	Signature used when the `CURSOR_SHARING` parameter is set to `EXACT`
`FORCE_MATCHING_SIGNATURE`	`NUMBER`	Signature used when the `CURSOR_SHARING` parameter is set to `FORCE`
`LAST_ACTIVE_TIME`	`DATE`	Time at which the query plan was last active
`BIND_DATA`	`RAW(2000)`	Bind data
`TYPECHECK_MEM`	`NUMBER`	Typecheck memory
`IO_CELL_OFFLOAD_ELIGIBLE_BYTES`	`NUMBER`	Number of I/O bytes which can be filtered by the Exadata storage system See Also: Oracle Exadata Storage Server Software documentation for more information
`IO_INTERCONNECT_BYTES`	`NUMBER`	Number of I/O bytes exchanged between Oracle Database and the storage system
`PHYSICAL_READ_REQUESTS`	`NUMBER`	Number of physical read I/O requests issued by the monitored SQL
`PHYSICAL_READ_BYTES`	`NUMBER`	Number of bytes read from disks by the monitored SQL
`PHYSICAL_WRITE_REQUESTS`	`NUMBER`	Number of physical write I/O requests issued by the monitored SQL
`PHYSICAL_WRITE_BYTES`	`NUMBER`	Number of bytes written to disks by the monitored SQL
`OPTIMIZED_PHY_READ_REQUESTS`	`NUMBER`	Number of physical read I/O requests from Database Smart Flash Cache issued by the monitored SQL
`LOCKED_TOTAL`	`NUMBER`	Total number of times the child cursor has been locked
`PINNED_TOTAL`	`NUMBER`	Total number of times the child cursor has been pinned
`IO_CELL_UNCOMPRESSED_BYTES`	`NUMBER`	Number of uncompressed bytes (that is, size after decompression) that are offloaded to the Exadata cells See Also: Oracle Exadata Storage Server Software documentation for more information
`IO_CELL_OFFLOAD_RETURNED_BYTES`	`NUMBER`	Number of bytes that are returned by the Exadata cell for smart scan only (that is, not including bytes for other database I/O) See Also: Oracle Exadata Storage Server Software documentation for more information

1.3 V$SQLTEXT

V$SQLTEXT displays the text of SQL statements belonging to shared SQL cursors in the SGA.

Column	Datatype	Description
`ADDRESS`	`RAW(4 \| 8)`	Used with `HASH_VALUE` to uniquely identify a cached cursor
`HASH_VALUE`	`NUMBER`	Used with `ADDRESS` to uniquely identify a cached cursor
`SQL_ID`	`VARCHAR2(13)`	SQL identifier of a cached cursor
`COMMAND_TYPE`	`NUMBER`	Code for the type of SQL statement (`SELECT`, `INSERT`, and so on)
`PIECE`	`NUMBER`	Number used to order the pieces of SQL text
`SQL_TEXT`	`VARCHAR2(64)`	A column containing one piece of the SQL text

1.4 V$SQL_PLAN

V$SQL_PLAN contains the execution plan information for each child cursor loaded in the library cache.

Column	Datatype	Description
`ADDRESS`	`RAW(4 \| 8)`	Address of the handle to the parent for this cursor
`HASH_VALUE`	`NUMBER`	Hash value of the parent statement in the library cache. The two columns `ADDRESS` and `HASH_VALUE` can be used to join with `V$SQLAREA` to add the cursor-specific information.
`SQL_ID`	`VARCHAR2(13)`	SQL identifier of the parent cursor in the library cache
`PLAN_HASH_VALUE`	`NUMBER`	Numerical representation of the SQL plan for the cursor. Comparing one `PLAN_HASH_VALUE` to another easily identifies whether or not two plans are the same (rather than comparing the two plans line by line).
`CHILD_ADDRESS`	`RAW(4 \| 8)`	Address of the child cursor
`CHILD_NUMBER`	`NUMBER`	Number of the child cursor that uses this execution plan. The columns `ADDRESS`, `HASH_VALUE`, and `CHILD_NUMBER` can be used to join with `V$SQL` to add the child cursor-specific information.
`TIMESTAMP`	`DATE`	Date and time when the execution plan was generated
`OPERATION`	`VARCHAR2(30)`	Name of the internal operation performed in this step (for example, `TABLE ACCESS`)
`OPTIONS`	`VARCHAR2(30)`	A variation on the operation described in the `OPERATION` column (for example, `FULL`)
`OBJECT_NODE`	`VARCHAR2(40)`	Name of the database link used to reference the object (a table name or view name). For local queries that use parallel execution, this column describes the order in which output from operations is consumed.
`OBJECT#`	`NUMBER`	Object number of the table or the index
`OBJECT_OWNER`	`VARCHAR2(30)`	Name of the user who owns the schema containing the table or index
`OBJECT_NAME`	`VARCHAR2(30)`	Name of the table or index
`OBJECT_ALIAS`	`VARCHAR2(65)`	Alias for the object
`OBJECT_TYPE`	`VARCHAR2(20)`	Type of the object
`OPTIMIZER`	`VARCHAR2(20)`	Current mode of the optimizer for the first row in the plan (statement line), for example, `CHOOSE`. When the operation is a database access (for example, `TABLE ACCESS`), this column indicates whether or not the object is analyzed.
`ID`	`NUMBER`	A number assigned to each step in the execution plan
`PARENT_ID`	`NUMBER`	ID of the next execution step that operates on the output of the current step
`DEPTH`	`NUMBER`	Depth (or level) of the operation in the tree. It is not necessary to issue a `CONNECT BY` statement to get the level information, which is generally used to indent the rows from the `PLAN_TABLE` table. The root operation (statement) is level 0.
`POSITION`	`NUMBER`	Order of processing for all operations that have the same `PARENT_ID`
`SEARCH_COLUMNS`	`NUMBER`	Number of index columns with start and stop keys (that is, the number of columns with matching predicates)
`COST`	`NUMBER`	Cost of the operation as estimated by the optimizer's cost-based approach. For statements that use the rule-based approach, this column is null.
`CARDINALITY`	`NUMBER`	Estimate, by the cost-based optimizer, of the number of rows produced by the operation
`BYTES`	`NUMBER`	Estimate, by the cost-based optimizer, of the number of bytes produced by the operation
`OTHER_TAG`	`VARCHAR2(35)`	Describes the contents of the `OTHER` column. See `EXPLAIN PLAN` for values.
`PARTITION_START`	`VARCHAR2(64)`	Start partition of a range of accessed partitions
`PARTITION_STOP`	`VARCHAR2(64)`	Stop partition of a range of accessed partitions
`PARTITION_ID`	`NUMBER`	Step that computes the pair of values of the `PARTITION_START` and `PARTITION_STOP` columns
`OTHER`	`VARCHAR2(4000)`	Other information specific to the execution step that users may find useful. See `EXPLAIN PLAN` for values.
`DISTRIBUTION`	`VARCHAR2(20)`	Stores the method used to distribute rows from producer query servers to consumer query servers
`CPU_COST`	`NUMBER`	CPU cost of the operation as estimated by the optimizer's cost-based approach. For statements that use the rule-based approach, this column is null.
`IO_COST`	`NUMBER`	I/O cost of the operation as estimated by the optimizer's cost-based approach. For statements that use the rule-based approach, this column is null.
`TEMP_SPACE`	`NUMBER`	Temporary space usage of the operation (sort or hash-join) as estimated by the optimizer's cost-based approach. For statements that use the rule-based approach, this column is null.
`ACCESS_PREDICATES`	`VARCHAR2(4000)`	Predicates used to locate rows in an access structure. For example, start or stop predicates for an index range scan.
`FILTER_PREDICATES`	`VARCHAR2(4000)`	Predicates used to filter rows before producing them
`PROJECTION`	`VARCHAR2(4000)`	Expressions produced by the operation
`TIME`	`NUMBER`	Elapsed time (in seconds) of the operation as estimated by the optimizer's cost-based approach. For statements that use the rule-based approach, this column is null.
`QBLOCK_NAME`	`VARCHAR2(30)`	Name of the query block
`REMARKS`	`VARCHAR2(4000)`	Remarks
`OTHER_XML`	`CLOB`	Provides extra information specific to an execution step of the execution plan. The content of this column is structured using XML since multiple pieces of information can be stored there. This includes: · Name of the schema against which the query was parsed · Release number of the Oracle Database that produced the explain plan · Hash value associated with the execution plan · Name (if any) of the outline or the SQL profile used to build the execution plan · Indication of whether or not dynamic sampling was used to produce the plan · The outline data, a set of optimizer hints that can be used to regenerate the same plan

二. 查看GV$ 视图的定义语句

/* Formatted on 2011/1/10 15:54:44 (QP5 v5.115.810.9015) */

SELECT view_definition

FROM v$fixed_view_definition

WHERE view_name = 'GV$SQL';

可以使用上面的语句查询视图的定义语句。这里查询的是GV$, 因为V$视图也是根据GV$出来的。这个可以用上面的语句查询下V$SQL 就可以验证了。

GV$SQL的定义如下：

/* Formatted on 2011/1/10 16:08:04 (QP5 v5.115.810.9015) */

SELECT inst_id,kglnaobj,kglfnobj,kglobt03,kglobhs0

+ kglobhs1

+ kglobhs2

+ kglobhs3

+ kglobhs4

+ kglobhs5

+ kglobhs6

+ kglobt16,

kglobt08 + kglobt11,

kglobt10,

kglobt01,

DECODE (kglobhs6, 0, 0, 1),

DECODE (kglhdlmd, 0, 0, 1),

kglhdlkc,kglobt04,kglobt05,kglobt48, kglobt35,kglobpc6,kglhdldc,

SUBSTR (TO_CHAR (kglnatim, 'YYYY-MM-DD/HH24:MI:SS'), 1, 19),

kglhdivc, kglobt12, kglobt13, kglobwdw,

kglobt14, kglobwap, kglobwcc, kglobwcl,

kglobwui, kglobt42, kglobt43, kglobt15,

kglobt02,

DECODE (kglobt32, 0, 'NONE', 1, 'ALL_ROWS', 2, 'FIRST_ROWS',

3, 'RULE', 4, 'CHOOSE', 'UNKNOWN'),

kglobtn0, kglobcce, kglobcceh, kglobt17,

kglobt18, kglobts4, kglhdkmk, kglhdpar,

kglobtp0, kglnahsh, kglobt46, kglobt30,

kglobt09, kglobts5, kglobt48, kglobts0,

kglobt19, kglobts1, kglobt20, kglobt21,

kglobts2, kglobt06, kglobt07,

DECODE (kglobt28, 0, TO_NUMBER (NULL), kglobt28),

kglhdadr, kglobt29, DECODE (BITAND (kglobt00, 64), 64, 'Y', 'N'),

DECODE (kglobsta, 1, 'VALID', 2, 'VALID_AUTH_ERROR',

3, 'VALID_COMPILE_ERROR', 4, 'VALID_UNAUTH',

5, 'INVALID_UNAUTH', 6, 'INVALID'),

kglobt31,

SUBSTR (TO_CHAR (kglobtt0, 'YYYY-MM-DD/HH24:MI:SS'), 1, 19),

DECODE (kglobt33, 1, 'Y', 'N'),

DECODE (BITAND (kglobacs, 1), 1, 'Y', 'N'),

DECODE (BITAND (kglobacs, 2), 2, 'Y', 'N'),

DECODE (BITAND (kglobacs, 4), 4, 'Y', 'N'),

kglhdclt, kglobts3, kglobts7, kglobts6,

kglobt44, kglobt45, kglobt47, kglobt49,

kglobcla, kglobcbca, kglobt22, kglobt52,

kglobt53, kglobt54,kglobt55, kglobt56,

kglobt57, kglobt58, kglobt23, kglobt24,

kglobt59, kglobt53 - ( (kglobt55 + kglobt57) - kglobt52)

FROM x$kglcursor_child

GV$SQLTEXT 定义如下：

SELECT inst_id,

kglhdadr,

kglnahsh,

kglnasqlid,

kgloboct,

piece,

name

FROM x$kglna

WHERE kgloboct != 0

GV$SQLAREA 定义

/* Formatted on 2011/1/10 16:05:52 (QP5 v5.115.810.9015) */

SELECT inst_id, kglnaobj, kglfnobj, kglobt03,

kglobhs0 + + + kglobhs3

+ + + kglobhs6,

kglobt08 + kglobt11, kglobt10, kglobt01,

kglobccc, kglobclc, kglhdlmd, kglhdlkc,

kglobt04, kglobt05, kglobt48, kglobt35,

kglobpc6, kglhdldc,

SUBSTR (TO_CHAR (kglnatim, 'YYYY-MM-DD/HH24:MI:SS'), 1, 19),

kglhdivc, kglobt12, kglobt13, kglobwdw,

kglobt14, kglobwap, kglobwcc, kglobwcl,

kglobwui, kglobt42, kglobt43, kglobt15,

kglobt02,

DECODE (kglobt32, 0, 'NONE', 1, 'ALL_ROWS', 2, 'FIRST_ROWS',

3, 'RULE', 4, 'CHOOSE', 'UNKNOWN'),

kglobtn0, kglobcce, kglobcceh, kglobt17,

kglobt18, kglobts4, kglhdkmk, kglhdpar,

kglna hsh, kglobt46, kglobt30, kglobts0,

kglobt19, kglobts1, kglobt20, kglobt21,

kglobts2, kglobt06, kglobt07,

DECODE (kglobt28, 0, NULL, kglobt28),kglhdadr,

DECODE (BITAND (kglobt00, 64), 64, 'Y', 'N'),

DECODE (kglobsta, 1, 'VALID', 2, 'VALID_AUTH_ERROR', 3,

'VALID_COMPILE_ERROR',4, 'VALID_UNAUTH',5,

'INVALID_UNAUTH',6, 'INVALID'), kglobt31,kglobtt0,

DECODE (kglobt33, 1, 'Y', 'N'),

DECODE (BITAND (kglobacs, 1), 1, 'Y', 'N'),

DECODE (BITAND (kglobacs, 2), 2, 'Y', 'N'),

kglhdclt,kglobts3,kglobts7,kglobts6,

kglobt44,kglobt45,kglobt47,kglobt49,

kglobcla,kglobcbca,kglobt22,kglobt52,

kglobt53,kglobt54,kglobt55,kglobt56,

kglobt57, kglobt58, kglobt23,kglobt24,

kglobt59, kglobt53 - ( (kglobt55 + kglobt57) - kglobt52)

FROM x$kglcursor_child_sqlid

WHERE kglobt02 != 0

从上面的语句可以看出，这些视图都是根据x$视图来定义的。对于X$视图，在我以前的Blog里有说明：

Oracle 动态性能视图

http://www.cndba.cn/Dave/article/1449

在这篇blog的1.2节中对X$介绍：1.2 V$, V_$, GV$, X$ 视图说明

X$表包含了特定实例的各方面的信息，是Oracle数据库的运行基础，如当前的配置信息，连接到实例的会话，以及丰富而有价值的性能信息。 X$表并不是驻留在数据库文件的永久表或临时表。X$表仅仅驻留在内存中，当实例启动时，由Oracle应用程序动态创建，在内存中进行实时的维护。它们中的大多数至少需要装载或已经打开的数据库。X$表为SYS用户所拥有，并且是只读的。不能进行DML(更新，插入，删除)。X$表对数据库来说至关重要，所以Oracle不允许SYSDBA之外的用户直接访问，显示授权不被允许。

V$SQLTEXT：存储的是完整的SQL, 但是SQL是被分割。

V$SQLAREA：存储的SQL 和一些相关的信息，比如累计的执行次数，逻辑读，物理读等统计信息。

V$SQL：存储的是具体的SQL 和执行计划相关信息，实际上，v$sqlarea 可以看做 v$sql 根据 sqltext 等做了 group by 之后的信息。

v$sqltext中有内存中完整的sql语句，而其他两个视图都是部分sql语句；

但v$sqltext中没有该语句的统计信息，比如执行次数等。

这几个视图的小应用：

Oracle 实时查询最耗CPU资源的SQL语句

http://www.cndba.cn/Dave/article/1227

三. v$sql, v$sql_plan 与执行计划

有关执行计划的东西，参考我的Blog：

Oracle Explain Plan

Oracle Optimizer CBO RBO

http://www.cndba.cn/Dave/article/1458

实际上，看起来同样的一句SQL ，往往具有不同的执行计划, 如果是不同的数据库用户，那么相应的涉及的对象可能都不一样，如v$sql_plan下的：

`HASH_VALUE`	`NUMBER`	Hash value of the parent statement in the library cache. The two columns `ADDRESS` and `HASH_VALUE` can be used to join with `V$SQLAREA` to add the cursor-specific information.
`OBJECT#`	`NUMBER`	Object number of the table or the index
`OBJECT_OWNER`	`VARCHAR2(30)`	Name of the user who owns the schema containing the table or index
`OBJECT_NAME`	`VARCHAR2(30)`	Name of the table or index
`OPTIMIZER`	`VARCHAR2(20)`	Current mode of the optimizer for the first row in the plan (statement line), for example, `CHOOSE`. When the operation is a database access (for example, `TABLE ACCESS`), this column indicates whether or not the object is analyzed.