net.snowflake.client.jdbc

Class SnowflakeChunkDownloader

java.lang.Object

net.snowflake.client.jdbc.SnowflakeChunkDownloader

public class SnowflakeChunkDownloader
extends Object

Class for managing async download of offline result chunks

Created by jhuang on 11/12/14.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	SnowflakeChunkDownloader.Metrics

Constructor Summary

Constructors

Constructor and Description
SnowflakeChunkDownloader(int colCount, com.fasterxml.jackson.databind.JsonNode chunksData, int prefetchThreads, String qrmk, com.fasterxml.jackson.databind.JsonNode chunkHeaders, int networkTimeoutInMilli, boolean useJsonParser, long memoryLimit, boolean efficientChunkStorage) Constructor to initialize downloader

Method Summary

Modifier and Type	Method and Description
static long	getCurrentMemoryUsage()
SnowflakeResultChunk	getNextChunkToConsume() The method does the following:
void	releaseAllChunkMemoryUsage() release all existing chunk memory usage before close
SnowflakeChunkDownloader.Metrics	terminate() terminate the downloader

Methods inherited from class java.lang.Object

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

Constructor Detail

SnowflakeChunkDownloader

public SnowflakeChunkDownloader(int colCount,
                                com.fasterxml.jackson.databind.JsonNode chunksData,
                                int prefetchThreads,
                                String qrmk,
                                com.fasterxml.jackson.databind.JsonNode chunkHeaders,
                                int networkTimeoutInMilli,
                                boolean useJsonParser,
                                long memoryLimit,
                                boolean efficientChunkStorage)
                         throws SnowflakeSQLException

Constructor to initialize downloader

Parameters:

colCount - number of columns to expect

chunksData - JSON object contains all the chunk information

prefetchThreads - number of prefetch threads

qrmk - Query Result Master Key

chunkHeaders - JSON object contains information about chunk headers

networkTimeoutInMilli - network timeout

useJsonParser - should JsonParser be used instead of object

memoryLimit - memory limit for chunk buffer

efficientChunkStorage - use new efficient storage format

Throws:

SnowflakeSQLException

Method Detail

getCurrentMemoryUsage

public static long getCurrentMemoryUsage()

releaseAllChunkMemoryUsage

public void releaseAllChunkMemoryUsage()

release all existing chunk memory usage before close

getNextChunkToConsume

public SnowflakeResultChunk getNextChunkToConsume()
                                           throws InterruptedException,
                                                  SnowflakeSQLException

The method does the following:

1. free the previous chunk data and submit a new chunk to be downloaded

2. get next chunk to consume, if it is not ready for consumption, it waits until it is ready

Returns:

next SnowflakeResultChunk to be consumed

Throws:

InterruptedException - if downloading thread was interrupted

SnowflakeSQLException - if downloader encountered an error

terminate

public SnowflakeChunkDownloader.Metrics terminate()

terminate the downloader

Returns:

chunk downloader metrics collected over instance lifetime