[jira] [Commented] (CARBONDATA-4187) Performance Issue with Materialized views - increased loading time due to full refresh

[Akash R Nilugal (Jira)]

    [ https://issues.apache.org/jira/browse/CARBONDATA-4187?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17343909#comment-17343909 ]

Sushant Sammanwar commented on CARBONDATA-4187:
-----------------------------------------------

show materialized views
+--------+--------------------------------+-------+------------+--------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
|Database| Name| Status|Refresh Mode|Refresh Trigger Mode| Properties|
+--------+--------------------------------+-------+------------+--------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| default| fact_365_1_cell_1_hour|ENABLED| full| on_commit|'carbon.column.compressor'='snappy','flat_folder'='false','local_dictionary_enable'='true','local_dictionary_threshold'='10000','mv_related_tables'='fact_365_1_cell_1','refresh_mode'='full','refres...|
| default| fact_365_1_utrancell_1_hour|ENABLED| full| on_commit|'carbon.column.compressor'='snappy','flat_folder'='false','local_dictionary_enable'='true','local_dictionary_threshold'='10000','mv_related_tables'='fact_365_1_utrancell_1','refresh_mode'='full','r...|
| default| fact_365_1_lac_1_hour|ENABLED| full| on_commit|'carbon.column.compressor'='snappy','flat_folder'='false','local_dictionary_enable'='true','local_dictionary_threshold'='10000','mv_related_tables'='fact_365_1_lac_1','refresh_mode'='full','refresh...|
| default| fact_365_1_eutrancell_1_hour|ENABLED| full| on_commit|'carbon.column.compressor'='snappy','flat_folder'='false','local_dictionary_enable'='true','local_dictionary_threshold'='10000','mv_related_tables'='fact_365_1_eutrancell_1','refresh_mode'='full','...|
| default| fact_365_1_trx_1_hour|ENABLED| full| on_commit|'carbon.column.compressor'='snappy','flat_folder'='false','local_dictionary_enable'='true','local_dictionary_threshold'='10000','mv_related_tables'='fact_365_1_trx_1','refresh_mode'='full','refresh...|
| default|fact_365_1_eutranrelation_1_hour|ENABLED| full| on_commit|'carbon.column.compressor'='snappy','flat_folder'='false','local_dictionary_enable'='true','local_dictionary_threshold'='10000','mv_related_tables'='fact_365_1_eutranrelation_1','refresh_mode'='ful...|
+--------+--------------------------------+-------+------------+--------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

 
[|https://issues.apache.org/jira/secure/AddComment!default.jspa?id=13378301]

> Performance Issue with Materialized views - increased loading time due to full refresh
> --------------------------------------------------------------------------------------
>
>                 Key: CARBONDATA-4187
>                 URL: https://issues.apache.org/jira/browse/CARBONDATA-4187
>             Project: CarbonData
>          Issue Type: Bug
>          Components: core
>    Affects Versions: 2.1.0
>            Reporter: Sushant Sammanwar
>            Priority: Major
>              Labels: materializedviews, performance
>
> Hi Team ,
> We have been doing a POC by using Carbon 2.1.0 and created a wrapper code around carbon and deployed it as docker container.
> Concurrent data loading is happening in many tables.
> Our objective if get optimal performance for aggregated queries and using materialized views .
> Our observation is after creating MVs data loading is slow and not able to keep-up the pace of incoming data .
> Process is also consuming a lot of memory when MVs are created .
> Data is received in continuous manner and MVs are refreshed which is resulting in increased load time.
> Ideally MVs should only perform incremental refresh as it doesnot require to calculate old data again.
> But it seems the full refresh is causing high memory usages and increased loading time.
> Testing involved loading data without MVs for 6 hrs , then creating MVs and load data again for 4 hours.
> Loading time with MVs increased there creating backlog of data ( loaded only 1/5 th no. of rows than expected).
> Below are major bottlenecks observed :
> 1. High Memory consumption after creating MVs
> 2. MVs doing a full refresh
> Please find attached details of testing with list of tables.
> Below is definition of table :
> create table if not exists fact_365_1_eutrancell_1 (ts timestamp, metric STRING, tags_id STRING, value DOUBLE, epoch bigint) partitioned by (ts2 timestamp) STORED AS carbondata TBLPROPERTIES ('SORT_COLUMNS'='metric')
> Below is definition of MV :
> create materialized view if not exists fact_365_1_eutrancell_1_hour as select tags_id ,metric,timeseries(ts,'hour') as ts,sum(value),avg(value),min(value),max(value) from fact_365_1_eutrancell_1 group by metric, tags_id, timeseries(ts,'hour')
> Can you suggest why MV creation is slowing down the ingestion so much and what can be done to improve ?
> Is there any way to have incremental refresh of MV - refresh only that hour for which we are loading the data ?

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