RE: Effective way to pre-load data around 10 TB
The problem might be in HDD not performing fast enough, and also suffering from random reads (IgniteCache::preloadPartition at least tries to read sequentially). Also, do you have enough RAM to store all data? If not, you shouldn’t preload all the data, just the amount that fits into RAM. Anyway, I think that your best chance is to implement the same thing https://issues.apache.org/jira/browse/IGNITE-8873 does. E.g. you can try to backport the commit on top of 2.6. Stan From: Naveen Sent: 5 декабря 2018 г. 7:59 To: user@ignite.apache.org Subject: RE: Effective way to pre-load data around 10 TB Thanks Stan, this may take little longer time to implement, we are in hurry to build this functionality of preloading the data. Can someone correct me how to improve this pre-load process. This is how we are preloading. 1. Send an Async request for all the partitions with the below code, below loop will get repeated for all the caches we have for (int i = 0; i < affinity.partitions(); i++) { List cacheList = Arrays.asList(cacheName); affinityRunAsync= compute.affinityRunAsync(cacheList, i, new DataPreloadTask(cacheList, i)); } 2. Inside DataPreloadTask which is running on the Ignite node. I just execute scan query for the given partition and iterate thru the cursor. not doing anything else. IgniteCache igniteCache = localIgnite.cache(cacheName); try (QueryCursor> cursor = igniteCache.query(new ScanQuery().setPartition(partitionNo))) { for (Cache.Entry entry : cursor) { } } } However, this seems to be quite slow. Taking more than 3 hours to read one cache which has 400 M records. We have 30 such caches to load data, so not fining this so efficient. Can we improve this, we do have very powerful machines with 128 CPU, 2 TB RAM, HDD, our CPU utilization is also not so high when we are preloading the data. Changing thread pool size will have any impact this read ??? Thanks Naveen -- Sent from: http://apache-ignite-users.70518.x6.nabble.com/
RE: Effective way to pre-load data around 10 TB
Thanks Stan, this may take little longer time to implement, we are in hurry to build this functionality of preloading the data. Can someone correct me how to improve this pre-load process. This is how we are preloading. 1. Send an Async request for all the partitions with the below code, below loop will get repeated for all the caches we have for (int i = 0; i < affinity.partitions(); i++) { List cacheList = Arrays.asList(cacheName); affinityRunAsync= compute.affinityRunAsync(cacheList, i, new DataPreloadTask(cacheList, i)); } 2. Inside DataPreloadTask which is running on the Ignite node. I just execute scan query for the given partition and iterate thru the cursor. not doing anything else. IgniteCache igniteCache = localIgnite.cache(cacheName); try (QueryCursor> cursor = igniteCache.query(new ScanQuery().setPartition(partitionNo))) { for (Cache.Entry entry : cursor) { } } } However, this seems to be quite slow. Taking more than 3 hours to read one cache which has 400 M records. We have 30 such caches to load data, so not fining this so efficient. Can we improve this, we do have very powerful machines with 128 CPU, 2 TB RAM, HDD, our CPU utilization is also not so high when we are preloading the data. Changing thread pool size will have any impact this read ??? Thanks Naveen -- Sent from: http://apache-ignite-users.70518.x6.nabble.com/
RE: Effective way to pre-load data around 10 TB
Hi, Currently the best option is IgniteCache::preloadPartition method added in https://issues.apache.org/jira/browse/IGNITE-8873. There is a JIRA ticket to allow pre-loading data before the node joins the cluster: https://issues.apache.org/jira/browse/IGNITE-10152. Stan From: Naveen Sent: 29 ноября 2018 г. 12:39 To: user@ignite.apache.org Subject: Effective way to pre-load data around 10 TB HI We are using Ignite 2.6. AS we already know, after the cluster restart, every GET call gets data from DISK for the first time and loads into RAM and subsequent calls data will read from RAM only.. First time GET calls are 10 times slower than read from RAM, which we wanted to avoid by pre-loading the entire data into RAM after the cluster restart. So here am exploring efficient ways to read entire data once so that it will pre-load the data into RAM, so GET calls from client will be much faster. Running ScanQuery on all the partitions of the cache would be good way to read data very fast in very less time ? OR any other better ways of achieving the same Thanks Naveen -- Sent from: http://apache-ignite-users.70518.x6.nabble.com/