QuerySplitter (MetaModel module for relational JDBC databases 5.3.0 API)

java.lang.Object
- org.apache.metamodel.jdbc.QuerySplitter

```
public final class QuerySplitter
extends Object
```
The QuerySplitter class makes it possible to split up queries that are expected to yield a huge result set which may cause performance problems like OutOfMemoryError's or very long processing periods. The resulting queries will in union produce the same result, but in smaller bits (resultsets with less rows). Note that there is an initial performance-penalty associated with splitting the query since some queries will be executed in order to determine reasonable intervals to use for the resulting queries WHERE clauses.

See Also:

Query, DataContext

Field Summary

Fields
Modifier and Type Field Description

static long DEFAULT_MAX_ROWS

Constructor Summary

Constructors
Constructor Description

QuerySplitter(org.apache.metamodel.DataContext dc, org.apache.metamodel.query.Query q)

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`org.apache.metamodel.data.DataSet`	`executeQueries()`
`org.apache.metamodel.data.DataSet`	`executeQueries(List<org.apache.metamodel.query.Query> splitQueries)`
`long`	`getRowCount()`
`static boolean`	`isSplittable(org.apache.metamodel.query.Query q)`
`QuerySplitter`	`setMaxRows(long maxRows)`	Sets the desired maximum result set row count.
`List<org.apache.metamodel.query.Query>`	`splitQuery()`	Splits the query into several queries that will together yield the same result set

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - DEFAULT_MAX_ROWS
```
public static final long DEFAULT_MAX_ROWS
```
    See Also:
    
    Constant Field Values
- Constructor Detail
  - QuerySplitter
```
public QuerySplitter(org.apache.metamodel.DataContext dc,
                     org.apache.metamodel.query.Query q)
```
- Method Detail
  - splitQuery
```
public List<org.apache.metamodel.query.Query> splitQuery()
```
    Splits the query into several queries that will together yield the same result set
    
    Returns:
    
    a list of queries that can be executed to yield the same collective result as this QuerySplitter's query
  - isSplittable
```
public static boolean isSplittable(org.apache.metamodel.query.Query q)
```
  - getRowCount
```
public long getRowCount()
```
    Returns:
    
    the total number of rows expected from executing the query.
  - setMaxRows
```
public QuerySplitter setMaxRows(long maxRows)
```
    Sets the desired maximum result set row count. Note that this size cannot be guaranteed, but will serve as an indicator for determining the split-size
    
    Parameters:
    
    maxRows -
  - executeQueries
```
public org.apache.metamodel.data.DataSet executeQueries()
```
  - executeQueries
```
public org.apache.metamodel.data.DataSet executeQueries(List<org.apache.metamodel.query.Query> splitQueries)
```