Class SequenceRange
java.lang.Object
org.apache.derby.impl.sql.catalog.SequenceRange
- All Implemented Interfaces:
SequencePreallocator
Default Derby logic for determining how many values to pre-allocate for an identity column or sequence.
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Field Summary
FieldsModifier and TypeFieldDescriptionprivate int
private static final int
Default number of values to pre-allocate. -
Constructor Summary
ConstructorsConstructorDescription0-arg constructore needed to satisfy the SequencePreallocator contract.SequenceRange
(int rangeSize) -
Method Summary
Modifier and TypeMethodDescriptionint
nextRangeSize
(String schemaName, String sequenceName) This method returns the size of the next pre-allocated range for the specified sequence.
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Field Details
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DEFAULT_PREALLOCATION_COUNT
private static final int DEFAULT_PREALLOCATION_COUNTDefault number of values to pre-allocate. Other databases use a preallocation size of 20 (see DERBY-4437). We boosted this to 100 in order to get better concurrency, after fixing correctness problems in pre-allocation (see DERBY-5493).- See Also:
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_rangeSize
private int _rangeSize
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Constructor Details
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SequenceRange
public SequenceRange()0-arg constructore needed to satisfy the SequencePreallocator contract.
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SequenceRange
public SequenceRange(int rangeSize)
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Method Details
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nextRangeSize
Description copied from interface:SequencePreallocator
This method returns the size of the next pre-allocated range for the specified sequence. Names are case-sensitive, as specified in CREATE SEQUENCE and CREATE TABLE statements.
- Specified by:
nextRangeSize
in interfaceSequencePreallocator
- Parameters:
schemaName
- Name of schema holding the sequence.sequenceName
- Specific name of the sequence.
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