com.pivotal.gemfirexd

Enum Constants.QueryHints

java.lang.Object

java.lang.Enum<Constants.QueryHints>

com.pivotal.gemfirexd.Constants.QueryHints

All Implemented Interfaces:

Serializable, Comparable<Constants.QueryHints>

Enclosing interface:

Constants

public static enum Constants.QueryHints
extends Enum<Constants.QueryHints>

Possible values of GEMFIREXD-PROPERTIES property keys.

Keys are case-sensitive and enumeration.name() method should be used for appropriate key strings.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Constants.QueryHints.SizerHints SizerHint constant values which can be passed comma separated.

Enum Constant Summary

Enum Constants

Enum Constant and Description
bulkFetch
constraint Query Hint to force usage of index enforcing a particular constraint.
executionEngine Query hint to specify the execution engine for the query.
hashInitialCapacity
hashLoadFactor
hashMaxCapacity
index Query Hint to force usage of any particular index.
joinOrder Query Hint to override optimizer's choice of ordering tables.
joinStrategy To override default optimizer's choice of join strategy.
queryHDFS Query hint to specify whether to query HDFS data.
sizerHints Memory Analytics sizer query hints.
statementAlias Query Hint to alias an user query that will be shown in Visual Statistics Display (VSD) instead of system generated statement alias.
withSecondaries Query Hint to indicate inclusion of secondary buckets of partitioned tables while joining with virtual tables.

Method Summary

Modifier and Type	Method and Description
static Constants.QueryHints	valueOf(String name) Returns the enum constant of this type with the specified name.
static Constants.QueryHints[]	values() Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Detail

joinStrategy

public static final Constants.QueryHints joinStrategy

To override default optimizer's choice of join strategy.

Possible values NESTEDLOOP or HASH

This can be FROM clause as well as table optimizer hint, in other words, this can be mentioned between FROM clause and the first table name or after each table name.

examples:
SELECT a, b FROM -- GEMFIREXD-PROPERTIES joinStrategy=HASH \n userTable1 t1, userTable2 t2 WHERE t1.col1 = t2.col1

SELECT a, b FROM userTable1 t1 -- GEMFIREXD-PROPERTIES joinStrategy=HASH \n, userTable2 t2 WHERE t1.col1 = t2.col1

joinOrder

public static final Constants.QueryHints joinOrder

Query Hint to override optimizer's choice of ordering tables. Typically used in conjunction with joinStrategy.

Possible values are FIXED or UNFIXED, where FIXED will ensure ordering of the tables as appeared in the FROM list.

This can only be used with FROM clause, in other words, this can only be mentioned between FROM clause and the first table name.

example:
SELECT a, b FROM -- GEMFIREXD-PROPERTIES joinOrder=FIXED \n userTable1 t1, userTable2 t2 -- GEMFIREXD-PROPERTIES joinStrategy=HASH \n WHERE t1.col1 = t2.col1

index

public static final Constants.QueryHints index

Query Hint to force usage of any particular index.

Possible values are unqualified index name or NULL indicating table scan.

This can only be used within TableExpression and only on base tables. Cannot be specified for views or derived tables.

constraint

public static final Constants.QueryHints constraint

Query Hint to force usage of index enforcing a particular constraint. This is similar to index property but index is used via constraint name.

Possible values are unqualified constraint name of primary key, foreign key or unique constraint.

This can only be used within TableExpression and only on base tables.

hashInitialCapacity

public static final Constants.QueryHints hashInitialCapacity

hashLoadFactor

public static final Constants.QueryHints hashLoadFactor

hashMaxCapacity

public static final Constants.QueryHints hashMaxCapacity

bulkFetch

public static final Constants.QueryHints bulkFetch

withSecondaries

public static final Constants.QueryHints withSecondaries

Query Hint to indicate inclusion of secondary buckets of partitioned tables while joining with virtual tables.

If true, partitioned table's secondary bucket will be considered for routing and scanning while performing the join with virtual table output.

This can only be used on base tables or virtual tables.

example:
SELECT dsid(), count(1) from sys.members , userPartitionedTable t1 -- GEMFIREXD-PROPERTIES withSecondaries=true \n GROUP BY dsid() Following query will return Entry Size/Value Size for primary buckets only. SELECT * FROM sys.memoryAnalytics -- GEMFIREXD-PROPERTIES withSecondaries=false \n

statementAlias

public static final Constants.QueryHints statementAlias

Query Hint to alias an user query that will be shown in Visual Statistics Display (VSD) instead of system generated statement alias.

This can only be used in FROM clause i.e. immediately after the FROM clause and before the table name. WhiteSpace characters are not allowed as word separator.

example:
SELECT * FROM -- GEMFIREXD-PROPERTIES statementAlias=My_QUERY \n userTable t1 -- GEMFIREXD-PROPERTIES index=IDX_COL1 \n WHERE t1.col1 is not null

queryHDFS

public static final Constants.QueryHints queryHDFS

Query hint to specify whether to query HDFS data.

Possible values are 'true' or 'false'.

This can only be used as a table optimizer hint i.e. can only be specified immediately after each table name.

example:
SELECT * FROM userTable t1 -- GEMFIREXD-PROPERTIES queryHDFS=true \n WHERE t1.col1 is not null

executionEngine

public static final Constants.QueryHints executionEngine

Query hint to specify the execution engine for the query.

Possible values are 'Spark' or 'Store'.

This can only be used with FROM clause, in other words, this can only be mentioned between FROM clause and the first table name.

example:
SELECT * FROM userTable t1 -- GEMFIREXD-PROPERTIES executionEngine=Spark \n WHERE t1.col1 is not null

sizerHints

public static final Constants.QueryHints sizerHints

Memory Analytics sizer query hints.

See Also:

Constants.QueryHints.SizerHints

Method Detail

values

public static Constants.QueryHints[] values()

Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

for (Constants.QueryHints c : Constants.QueryHints.values())
    System.out.println(c);

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static Constants.QueryHints valueOf(String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

IllegalArgumentException - if this enum type has no constant with the specified name

NullPointerException - if the argument is null