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Oracle® Database Reference
11g Release 2 (11.2)

Part Number E17110-04
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PLAN_TABLE

PLAN_TABLE is automatically created as a global temporary table to hold the output of an EXPLAIN PLAN statement for all users. PLAN_TABLE is the default sample output table into which the EXPLAIN PLAN statement inserts rows describing execution plans.

While a PLAN_TABLE table is automatically set up for each user, you can use the SQL script utlxplan.sql to manually create a local PLAN_TABLE in your schema.

Column Datatype NULL Description
STATEMENT_ID VARCHAR2(30)   Value of the optional STATEMENT_ID parameter specified in the EXPLAIN PLAN statement
PLAN_ID NUMBER   Unique identifier of a plan in the database
TIMESTAMP DATE   Date and time when the EXPLAIN PLAN statement was generated
REMARKS VARCHAR2(4000)   Any comment (of up to 4000 bytes) you want to associate with each step of the explained plan. This column is used to indicate whether an outline or SQL Profile was used for the query.

If you need to add or change a remark on any row of the PLAN_TABLE, then use the UPDATE statement to modify the rows of the PLAN_TABLE.

OPERATION VARCHAR2(30)   Name of the internal operation performed in this step. In the first row generated for a statement, the column contains one of the following values:
  • DELETE STATEMENT

  • INSERT STATEMENT

  • SELECT STATEMENT

  • UPDATE STATEMENT

OPTIONS VARCHAR2(255)   A variation on the operation described in the OPERATION column
OBJECT_NODE VARCHAR2(128)   Name of the database link used to reference the object (a table name or view name). For local queries using parallel execution, this column describes the order in which output from operations is consumed.
OBJECT_OWNER VARCHAR2(30)   Owner of the table or index
OBJECT_NAME VARCHAR2(30)   Name of the table or index
OBJECT_ALIAS VARCHAR2(65)   Unique alias of a table or view in a SQL statement. For indexes, it is the object alias of the underlying table.
OBJECT_INSTANCE NUMBER(38)   Number corresponding to the ordinal position of the object as it appears in the original statement. The numbering proceeds from left to right, outer to inner with respect to the original statement text. View expansion results in unpredictable numbers.
OBJECT_TYPE VARCHAR2(30)   Modifier that provides descriptive information about the object; for example, NON-UNIQUE for indexes
OPTIMIZER VARCHAR2(255)   Current mode of the optimizer
SEARCH_COLUMNS NUMBER   Not currently used
ID NUMBER(38)   A number assigned to each step in the execution plan
PARENT_ID NUMBER(38)   ID of the next execution step that operates on the output of the ID step
DEPTH NUMBER(38)   Depth of the operation in the row source tree that the plan represents. The value can be used for indenting the rows in a plan table report.
POSITION NUMBER(38)   For the first row of output, this indicates the optimizer's estimated cost of executing the statement. For the other rows, it indicates the position relative to the other children of the same parent.
COST NUMBER(38)   Cost of the operation as estimated by the optimizer's query approach. Cost is not determined for table access operations. The value of this column does not have any particular unit of measurement; it is merely a weighted value used to compare costs of execution plans. The value of this column is a function of the CPU_COST and IO_COST columns.
CARDINALITY NUMBER(38)   Estimate by the query optimization approach of the number of rows accessed by the operation
BYTES NUMBER(38)   Estimate by the query optimization approach of the number of bytes accessed by the operation
OTHER_TAG VARCHAR2(255)   Describes the contents of the OTHER column:
  • SERIAL - Serial execution. Currently, SQL is not loaded in the OTHER column for this case.

  • SERIAL_FROM_REMOTE - Serial execution at a remote site.

  • PARALLEL_FROM_SERIAL - Serial execution. Output of step is partitioned or broadcast to parallel execution servers.

  • PARALLEL_TO_SERIAL - Parallel execution. Output of step is returned to serial query coordinator (QC) process.

  • PARALLEL_TO_PARALLEL - Parallel execution. Output of step is repartitioned to second set of parallel execution servers.

  • PARALLEL_COMBINED_WITH_PARENT - Parallel execution; Output of step goes to next step in same parallel process. No interprocess communication to parent.

  • PARALLEL_COMBINED_WITH_CHILD - Parallel execution. Input of step comes from prior step in same parallel process. No interprocess communication from child.

PARTITION_START VARCHAR2(255)   Start partition of a range of accessed partitions:
  • number - Start partition has been identified by the SQL compiler, and its partition number is given by number

  • KEY - Start partition will be identified at run time from partitioning key values

  • ROW REMOVE_LOCATION - Start partition (same as the stop partition) will be computed at run time from the location of each record being retrieved. The record location is obtained by a user or from a global index.

  • INVALID - Range of accessed partitions is empty

PARTITION_STOP VARCHAR2(255)   Stop partition of a range of accessed partitions:
  • number - Stop partition has been identified by the SQL compiler, and its partition number is given by number

  • KEY - Stop partition will be identified at run time from partitioning key values

  • ROW REMOVE_LOCATION - Stop partition (same as the start partition) will be computed at run time from the location of each record being retrieved. The record location is obtained by a user or from a global index.

  • INVALID - Range of accessed partitions is empty

PARTITION_ID NUMBER(38)   Step that has computed the pair of values of the PARTITION_START and PARTITION_STOP columns
OTHER LONG   Other information that is specific to the execution step that a user might find useful (see the OTHER_TAG column)
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

DISTRIBUTION VARCHAR2(30)   Method used to distribute rows from producer query servers to consumer query servers

See Also: Oracle Database Data Warehousing Guide for more information about consumer and producer query servers

CPU_COST NUMBER(38)   CPU cost of the operation as estimated by the query optimizer's approach. The value of this column is proportional to the number of machine cycles required for the operation. For statements that use the rule-based approach, this column is NULL.
IO_COST NUMBER(38)   I/O cost of the operation as estimated by the query optimizer's approach. The value of this column is proportional to the number of data blocks read by the operation. For statements that use the rule-based approach, this column is NULL.
TEMP_SPACE NUMBER(38)   Temporary space (in bytes) used by the operation as estimated by the query optimizer's approach. For statements that use the rule-based approach, or for operations that do not use any temporary space, 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(38)   Elapsed time (in seconds) of the operation as estimated by query optimization. For statements that use the rule-based approach, this column is NULL.
QBLOCK_NAME VARCHAR2(30)   Name of the query block (either system-generated or defined by the user with the QB_NAME hint)