Administration Guide

EXPLAIN_STREAM Table

The EXPLAIN_STREAM table represents the input and output data streams between individual operators and data objects. The data objects themselves are represented in the EXPLAIN_OBJECT table. The operators involved in a data stream are to be found in the EXPLAIN_OPERATOR table.

Table 132. EXPLAIN_STREAM Table

Column Name Data Type Nullable? Key? Description
EXPLAIN_REQUESTER CHAR(8) No FK Authorization ID of initiator of this Explain request.
EXPLAIN_TIME TIMESTAMP No FK Time of initiation for Explain request.
SOURCE_NAME CHAR(8) No FK Name of the package running when the dynamic statement was explained or name of the source file when the static SQL was explained.
SOURCE_SCHEMA CHAR(8) No FK Schema, or qualifier, of source of Explain request.
EXPLAIN_LEVEL CHAR(1) No FK Level of Explain information for which this row is relevant.
STMTNO SMALLINT No FK Statement number within package to which this explain information is related.
SECTNO SMALLINT No FK Section number within package to which this explain information is related.
STREAM_ID SMALLINT No No Unique ID for this data stream within the specified operator.
SOURCE_TYPE CHAR(1) No No Indicates the source of this data stream:

O
Operator
D
Data Object

SOURCE_ID SMALLINT No No Unique ID for the operator within this query that is the source of this data stream. Set to -1 if SOURCE_TYPE is 'D'.
TARGET_TYPE CHAR(1) No No Indicates the target of this data stream:

O
Operator
D
Data Object

TARGET_ID SMALLINT No No Unique ID for the operator within this query that is the target of this data stream. Set to -1 if TARGET_TYPE is 'D'.
OBJECT_SCHEMA CHAR(8) Yes No Schema to which the affected data object belongs. Set to null if both SOURCE_TYPE and TARGET_TYPE are 'O'.
OBJECT_NAME VARCHAR(18) Yes No Name of the object that is the subject of data stream. Set to null if both SOURCE_TYPE and TARGET_TYPE are 'O'.
STREAM_COUNT DOUBLE No No Estimated cardinality of data stream.
COLUMN_COUNT SMALLINT No No Number of columns in data stream.
PREDICATE_ID SMALLINT No No If this stream is part of a subquery for a predicate, the predicate ID will be reflected here, otherwise the column is set to -1.
COLUMN_NAMES CLOB(64K) Yes No This column contains the names and ordering information of the columns involved in this stream.
These names will be in the format of:
NAME1(A)+NAME2(D)+NAME3+NAME4

Where (A) indicates a column in ascending order, (D) indicates a column in descending order, and no ordering information indicates that either the column is not ordered or ordering is not relevant.
PMID SMALLINT No No Partitioning map ID.
SINGLE_NODE CHAR(5) Yes No Indicates if this data stream is on a single or multiple partitions:

MULT
On multiple partitions
COOR
On coordinator node
HASH
Directed using hashing
RID
Directed using the row ID
FUNC
Directed using a function (PARTITION() or NODENUMBER())
CORR
Directed using a correlation value

PARTITION_COLUMNS CLOB(64K) Yes No List of columns this data stream is partitioned on.

Column Name	Data Type	Nullable?	Key?	Description
EXPLAIN_REQUESTER	CHAR(8)	No	FK	Authorization ID of initiator of this Explain request.
EXPLAIN_TIME	TIMESTAMP	No	FK	Time of initiation for Explain request.
SOURCE_NAME	CHAR(8)	No	FK	Name of the package running when the dynamic statement was explained or name of the source file when the static SQL was explained.
SOURCE_SCHEMA	CHAR(8)	No	FK	Schema, or qualifier, of source of Explain request.
EXPLAIN_LEVEL	CHAR(1)	No	FK	Level of Explain information for which this row is relevant.
STMTNO	SMALLINT	No	FK	Statement number within package to which this explain information is related.
SECTNO	SMALLINT	No	FK	Section number within package to which this explain information is related.
STREAM_ID	SMALLINT	No	No	Unique ID for this data stream within the specified operator.
SOURCE_TYPE	CHAR(1)	No	No	Indicates the source of this data stream: O Operator D Data Object
SOURCE_ID	SMALLINT	No	No	Unique ID for the operator within this query that is the source of this data stream. Set to -1 if SOURCE_TYPE is 'D'.
TARGET_TYPE	CHAR(1)	No	No	Indicates the target of this data stream: O Operator D Data Object
TARGET_ID	SMALLINT	No	No	Unique ID for the operator within this query that is the target of this data stream. Set to -1 if TARGET_TYPE is 'D'.
OBJECT_SCHEMA	CHAR(8)	Yes	No	Schema to which the affected data object belongs. Set to null if both SOURCE_TYPE and TARGET_TYPE are 'O'.
OBJECT_NAME	VARCHAR(18)	Yes	No	Name of the object that is the subject of data stream. Set to null if both SOURCE_TYPE and TARGET_TYPE are 'O'.
STREAM_COUNT	DOUBLE	No	No	Estimated cardinality of data stream.
COLUMN_COUNT	SMALLINT	No	No	Number of columns in data stream.
PREDICATE_ID	SMALLINT	No	No	If this stream is part of a subquery for a predicate, the predicate ID will be reflected here, otherwise the column is set to -1.
COLUMN_NAMES	CLOB(64K)	Yes	No	This column contains the names and ordering information of the columns involved in this stream. These names will be in the format of: NAME1(A)+NAME2(D)+NAME3+NAME4 Where (A) indicates a column in ascending order, (D) indicates a column in descending order, and no ordering information indicates that either the column is not ordered or ordering is not relevant.
PMID	SMALLINT	No	No	Partitioning map ID.
SINGLE_NODE	CHAR(5)	Yes	No	Indicates if this data stream is on a single or multiple partitions: MULT On multiple partitions COOR On coordinator node HASH Directed using hashing RID Directed using the row ID FUNC Directed using a function (PARTITION() or NODENUMBER()) CORR Directed using a correlation value
PARTITION_COLUMNS	CLOB(64K)	Yes	No	List of columns this data stream is partitioned on.

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