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SQL Anywhere 12.0.0 » SQL Anywhere Server - SQL Usage » Query optimization and execution » Reading execution plans

 

Execution plan abbreviations

Following are the abbreviations that you see in execution plans.

Short text plan Long text plan Additional information
Costed Best Plan

The optimizer generates and costs access plans for a given query. During this process the current best plan maybe replaced by a new best plan found to have a lower cost estimate. The last best plan is the execution plan used to execute the statement. Costed Best Plans indicates the number of times the optimizer found a better plan than the current best plan. A low number indicates that the best plan was determined early in the enumeration process. Since the optimizer starts the enumeration process at least once for each query block in the given statement, Costed Best Plans represents the cumulative count. See How the optimizer works.

Costed Plans

Many plans generated by the optimizer are found to be too expensive compared to the best plan found so far. Costed Plans represents the number of partial or complete plans the optimizer considered during the enumeration processes for a given statement.

DELETE Delete The root node of a DELETE operation. See DELETE statement.
DistH HashDistinct

See HashDistinct algorithm (DistH).

DistO OrderedDistinct

See OrderedDistinct algorithm (DistO).

DP DecodePostings

See DecodePostings (DP).

DT DerivedTable

See DerivedTable algorithm (DT).

EAH HashExceptAll

See Except algorithms (EAH, EAM, EH, EM).

EAM MergeExceptAll

See Except algorithms (EAH, EAM, EH, EM).

EH HashExcept

See Except algorithms (EAH, EAM, EH, EM).

EM MergeAccept

See Except algorithms (EAH, EAM, EH, EM).

Exchange Exchange

See Exchange algorithm (Exchange).

Filter Filter

See Filter algorithms (Filter, PreFilter).

GrByH HashGroupBy

See HashGroupBy algorithm (GrByH).

GrByHClust HashGroupByClustered

See ClusteredHashGroupBy algorithm (GrByHClust).

GrByHSets HashGroupBySets

See HashGroupBySets algorithm (GrByHSets).

GrByO OrderedGroupBy

See OrderedGroupBy algorithm (GrByO).

GrByOSets OrderedGroupBySets

See OrderedGroupBySets algorithm (GrByOSets).

GrByS SingleRowGroupBy

See SingleRowGroupBy algorithm (GrByS).

GrBySSets SortedGroupBySets

See SortedGroupBySets algorithm (GrBySSets).

HF HashFilter

See Hash filter algorithms (HF, HFP).

HFP ParallelHashFilter

See Hash filter algorithms (HF, HFP).

HTS HashTableScan

See HashTableScan method (HTS).

IAH HashIntersectAll

See Intersect algorithms (IH, IM, IAH, IAM).

IAM MergeIntersectAll

See Intersect algorithms (IH, IM, IAH, IAM).

IH HashIntersect

See Intersect algorithms (IH, IM, IAH, IAM).

IM MergeIntersect

See Intersect algorithms (IH, IM, IAH, IAM).

IN InList

See InList algorithm (IN).

table-name<index-name>

IndexScan, ParallelIndexScan

In a graphical plan, an index scan appears as an index name in a trapezoid. See IndexScan method.

INSENSITIVE Insensitive

See Intersect algorithms (IH, IM, IAH, IAM).

INSERT Insert

Root node of an insert operation. See INSERT statement.

IO IndexOnlyScan, ParallelIndexOnlyScan

See IndexOnlyScan method (IO), and ParallelIndexScan method.

JH HashJoin

See HashJoin algorithms (JH, JHSP, JHFO, JHAP, JHO, JHPO).

JHS HashSemijoin

See HashSemijoin algorithm (JHS).

JHSP ParallelHashSemijoin

See HashJoin algorithms (JH, JHSP, JHFO, JHAP, JHO, JHPO).

JHFO Full Outer HashJoin

See HashJoin algorithms (JH, JHSP, JHFO, JHAP, JHO, JHPO).

JHA HashAntisemijoin

See HashAntisemijoin algorithm (JHA).

JHAP ParallelHashAntisemijoin

See HashJoin algorithms (JH, JHSP, JHFO, JHAP, JHO, JHPO).

JHO Left Outer HashJoin

See HashJoin algorithms (JH, JHSP, JHFO, JHAP, JHO, JHPO).

JHP ParallelHashJoin

See HashJoin algorithms (JH, JHSP, JHFO, JHAP, JHO, JHPO).

JHPO ParallelLeftOuterHashJoin

See HashJoin algorithms (JH, JHSP, JHFO, JHAP, JHO, JHPO).

JHR RecursiveHashJoin

See RecursiveHashJoin algorithm (JHR).

JHRO RecursiveLeftOuterHashJoin

See RecursiveLeftOuterHashJoin algorithm (JHRO).

JM MergeJoin

See MergeJoin algorithms (JM, JMFO, JMO).

JMFO Full Outer MergeJoin

See MergeJoin algorithms (JM, JMFO, JMO).

JMO Left Outer MergeJoin

See MergeJoin algorithms (JM, JMFO, JMO).

JNL NestedLoopsJoin

See NestedLoopsJoin algorithms (JNL, JNLFO, JNLO).

JNLA NestedLoopsAntisemijoin

See NestedLoopsAntisemijoin algorithm (JNLA).

JNLFO Full Outer NestedLoopsJoin

See NestedLoopsJoin algorithms (JNL, JNLFO, JNLO).

JNLO Left Outer NestedLoopsJoin

See NestedLoopsJoin algorithms (JNL, JNLFO, JNLO).

JNLS NestedLoopsSemijoin

See NestedLoopsSemijoin algorithm (JNLS).

KEYSET Keyset

Indicates a keyset-driven cursor. See SQL Anywhere cursors.

LOAD Load

Root node of a load operation. See LOAD TABLE statement.

MultiIdx MultipleIndexScan

See MultipleIndexScan method (MultIdx).

OpenString OpenString

See OpenString algorithm (OpenString).

Optimization Time

The total time spent by the optimizer during all enumeration processes for a given statement.

PC ProcCall

Procedure call (table function). See ProcCall algorithm (PC).

PreFilter PreFilter

See Filter algorithms (Filter, PreFilter).

RL RowLimit

See RowLimit algorithm (RL).

ROWID RowIdScan

In a graphical plan, a row ID scan appears as a table name in a rectangle. See RowIdScan method (ROWID).

ROWS RowConstructor

See RowConstructor algorithm (ROWS).

RR RowReplicate

See RowReplicate algorithm (RR).

RT RecursiveTable

See RecursiveTable algorithm (RT).

RU RecursiveUnion

See RecursiveUnion algorithm (RU).

SELECT Select

Root node of a SELECT operation. See SELECT statement.

seq TableScan, ParallelTableScan

In a graphical plan, table scans appear as a table name in a rectangle. See TableScan method (seq), and ParallelTableScan method.

Sort Sort

Indexed or merge sort. See Sort algorithm (Sort).

SrtN SortTopN

See SortTopN algorithm (SrtN).

TermBreak TermBreak

The full text search TermBreaker algorithm. See How to alter a text index.

UA UnionAll

See UnionAll algorithm (UA).

UPDATE Update

The root node of an UPDATE operation. See UPDATE statement.

Window Window

See Window algorithm (Window).

Work Work table

An internal node that represents an intermediate result.

 Common statistics used in the plan
 Common estimates used in the plan
 Items in the plan related to SELECT, INSERT, UPDATE, and DELETE
 Items in the plan related to locks
 Items in the plan related to scans
 Items in the plan related to index scans
 Items in the plan related to joins, filter, and prefilter
 Items in the plan related to hash filter
 Items in the plan related to Union
 Items in the plan related to GROUP BY
 Items in the plan related to DISTINCT
 Items in the plan related to IN LIST
 Items in the plan related to SORT
 Items in the plan related to row limits