[GitHub] [hudi] yyh2954360585 commented on issue #9471: [SUPPORT] When using Deltasteamer JdbcSource to extract data, there are issues with data loss and slow query of source side data

2023-08-21 Thread via GitHub


yyh2954360585 commented on issue #9471:
URL: https://github.com/apache/hudi/issues/9471#issuecomment-1687328500

   > > @yyh2954360585 JDBC is slow and put lot of load on source system. So 
full query a full query on large table can cause high load or even downtime to 
the database server. You can set the value of source-limit according to your 
dataset and requirement. You can even set it to a very high value.
   > 
   > If I set source limit=1000, then I can only extract 1000 pieces of data 
from the source table, which is not reasonable. Because it has no offset.
   > 
   > 
https://github.com/apache/hudi/blob/ba5ab8ca46863a67023e7172fb16a9a36d3b5acb/hudi-utilities/src/main/java/org/apache/hudi/utilities/sources/JdbcSource.java#L239-L252
   
   So there will be another issue. If I have a table with a data volume of 10 
million and do not set the source limit, it will perform a full query on the 
source table. PpdQuery is a subquery that, according to the SQL execution plan, 
executes the subquery first and then the outer layer. If using jdbc. fetchsize, 
the condition for fetchsize will only be at the outermost layer


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[GitHub] [hudi] yyh2954360585 commented on issue #9471: [SUPPORT] When using Deltasteamer JdbcSource to extract data, there are issues with data loss and slow query of source side data

2023-08-21 Thread via GitHub


yyh2954360585 commented on issue #9471:
URL: https://github.com/apache/hudi/issues/9471#issuecomment-1687318170

   > > @yyh2954360585 JDBC is slow and put lot of load on source system. So 
full query a full query on large table can cause high load or even downtime to 
the database server. You can set the value of source-limit according to your 
dataset and requirement. You can even set it to a very high value.
   > 
   > If I set source limit=1000, then I can only extract 1000 pieces of data 
from the source table, which is not reasonable. Because it has no offset
   
   
https://github.com/apache/hudi/blob/ba5ab8ca46863a67023e7172fb16a9a36d3b5acb/hudi-utilities/src/main/java/org/apache/hudi/utilities/sources/JdbcSource.java#L239-L252


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[GitHub] [hudi] yyh2954360585 commented on issue #9471: [SUPPORT] When using Deltasteamer JdbcSource to extract data, there are issues with data loss and slow query of source side data

2023-08-21 Thread via GitHub


yyh2954360585 commented on issue #9471:
URL: https://github.com/apache/hudi/issues/9471#issuecomment-1687317983

   
https://github.com/apache/hudi/blob/ba5ab8ca46863a67023e7172fb16a9a36d3b5acb/hudi-utilities/src/main/java/org/apache/hudi/utilities/sources/JdbcSource.java#L239-L252


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[GitHub] [hudi] yyh2954360585 commented on issue #9471: [SUPPORT] When using Deltasteamer JdbcSource to extract data, there are issues with data loss and slow query of source side data

2023-08-21 Thread via GitHub


yyh2954360585 commented on issue #9471:
URL: https://github.com/apache/hudi/issues/9471#issuecomment-1687316048

   
https://github.com/apache/hudi/blob/ba5ab8ca46863a67023e7172fb16a9a36d3b5acb/hudi-utilities/src/main/java/org/apache/hudi/utilities/sources/JdbcSource.java#L240


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[GitHub] [hudi] yyh2954360585 commented on issue #9471: [SUPPORT] When using Deltasteamer JdbcSource to extract data, there are issues with data loss and slow query of source side data

2023-08-21 Thread via GitHub


yyh2954360585 commented on issue #9471:
URL: https://github.com/apache/hudi/issues/9471#issuecomment-1687304692

   > @yyh2954360585 JDBC is slow and put lot of load on source system. So full 
query a full query on large table can cause high load or even downtime to the 
database server. You can set the value of source-limit according to your 
dataset and requirement. You can even set it to a very high value.
   
   If I set source limit=1000, then I can only extract 1000 pieces of data from 
the source table, which is not reasonable. Because it has no offset


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