Package org.apache.iotdb.db.query.control

Class QueryResourceManager

java.lang.Object

org.apache.iotdb.db.query.control.QueryResourceManager

public class QueryResourceManager
extends java.lang.Object

QueryResourceManager manages resource (file streams) used by each query job, and assign Ids to the jobs. During the life cycle of a query, the following methods must be called in strict order:

1. assignQueryId - get an Id for the new query.

2. getQueryDataSource - open files for the job or reuse existing readers.

3. endQueryForGivenJob - release the resource used by this job.

Method Summary

Modifier and Type	Method	Description
long	assignCompactionQueryId()	Register a query id for compaction.
long	assignQueryId(boolean isDataQuery)	Register a new query.
void	endQuery(long queryId)	Whenever the jdbc request is closed normally or abnormally, this method must be invoked.
static QueryResourceManager	getInstance()
QueryDataSource	getQueryDataSource(org.apache.iotdb.commons.path.PartialPath selectedPath, QueryContext context, org.apache.iotdb.tsfile.read.filter.basic.Filter timeFilter, boolean ascending)
QueryFileManager	getQueryFileManager()
void	initQueryDataSourceCache(java.util.Map<DataRegion,java.util.List<org.apache.iotdb.commons.path.PartialPath>> processorToSeriesMap, QueryContext context, org.apache.iotdb.tsfile.read.filter.basic.Filter timeFilter)	The method is called in mergeLock() when executing query.
void	registerTempExternalSortFile(long queryId, IExternalSortFileDeserializer deserializer)	register temporary file generated by external sort for resource release.
void	writeQueryFileInfo()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

getInstance

public static QueryResourceManager getInstance()

assignQueryId

public long assignQueryId(boolean isDataQuery)

Register a new query. When a query request is created firstly, this method must be invoked.

assignCompactionQueryId

public long assignCompactionQueryId()

Register a query id for compaction. The name of the compaction thread is 'pool-x-IoTDB-Compaction-xx', xx in which is usually an integer from 0 to MAXCOMPACTION_THREAD_NUM. We use the following rules to define query id for compaction:
queryId = xx + Long.MIN_VALUE

registerTempExternalSortFile

public void registerTempExternalSortFile(long queryId,
                                         IExternalSortFileDeserializer deserializer)

register temporary file generated by external sort for resource release.

Parameters:

queryId - query job id

deserializer - deserializer of temporary file in external sort.

initQueryDataSourceCache

public void initQueryDataSourceCache(java.util.Map<DataRegion,java.util.List<org.apache.iotdb.commons.path.PartialPath>> processorToSeriesMap,
                                     QueryContext context,
                                     org.apache.iotdb.tsfile.read.filter.basic.Filter timeFilter)
                              throws QueryProcessException

The method is called in mergeLock() when executing query. This method will get all the QueryDataSource needed for this query and put them in the cachedQueryDataSourcesMap.

Parameters:

processorToSeriesMap - Key: processor of the virtual storage group. Value: selected series under the virtual storage group

Throws:

QueryProcessException

getQueryDataSource

public QueryDataSource getQueryDataSource(org.apache.iotdb.commons.path.PartialPath selectedPath,
                                          QueryContext context,
                                          org.apache.iotdb.tsfile.read.filter.basic.Filter timeFilter,
                                          boolean ascending)
                                   throws StorageEngineException,
                                          QueryProcessException

Parameters:

selectedPath - MeasurementPath or AlignedPath, even if it contains only one sub sensor of an aligned device, it should be AlignedPath instead of MeasurementPath

Throws:

StorageEngineException

QueryProcessException

endQuery

public void endQuery(long queryId)
              throws StorageEngineException

Whenever the jdbc request is closed normally or abnormally, this method must be invoked. All query tokens created by this jdbc request must be cleared.

Throws:

StorageEngineException

writeQueryFileInfo

public void writeQueryFileInfo()

getQueryFileManager

public QueryFileManager getQueryFileManager()