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Full Incremental Cache

I am using denodo 8.I want to use full incremental cache in a base view. I could see from denodo documentation that a field has to be created in the base view first to fetch last modification date of a view. Could you please let me know the steps.
user
16-05-2023 09:16:18 -0400
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5 Answers

Hi, The timestamp column must already exist in the source table from which the base view or derived view is created. While using the Incremental Cache, a timestamp column is a requirement so that it can be used as a condition to enforce the data to be loaded incrementally. Below is the syntax for the condition: lastmodifieddate > '@LASTCACHEREFRESH' Additionally, Virtual DataPort must support pushing conditions down to the source over the last inserted/updated fields. If the condition cannot be pushed down to the source, Incremental mode is useless because the source will be forced to return the entire result set. I suggest reading more about this in the “[Incremental Mode](https://community.denodo.com/docs/html/browse/8.0/en/vdp/administration/cache_module/cache_modes/incremental_mode#:~:text=Incremental%20Mode-,Incremental%20Mode,-The%20incremental%20mode)” section of the Virtual DataPort Administration Guide. Within this section, I recommend reading the “[Requirements a View Has to meet to Support Incremental Queries](https://community.denodo.com/docs/html/browse/8.0/en/vdp/administration/cache_module/cache_modes/incremental_mode#requirements-a-view-has-to-meet-to-support-incremental-queries)” section. Hope this helps!
Denodo Team
17-05-2023 09:30:58 -0400
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Hi, Is it mandatory for all source tables in data sources in Denodo to contain the mentioned timestamp column for fetching the last modified date? Please let me know.
user
17-05-2023 09:53:07 -0400
Hi, It is mandatory to have a timestamp field in the source table to have accurate transaction dates of when it was inserted or updated. Having a timestamp column in the source table is a requirement to use Incremental Mode Cache since it requires a condition to be specified with ‘LASTCACHEREFRESH’, other cache modes do not have this requirement. Hope this helps!
Denodo Team
18-05-2023 04:28:54 -0400
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Hi Team I have created an incremental load view in scheduler for incremental cache. Incremental cache mode is disabled for all base views.Based on the snapshot date, we are able to load incremental records to our derived view by job in scheduler. We are facing count difference when records got deleted in source table. We dont prefer base view refresh.Without refreshing base view, How can we identify deleted records from source table?
user
04-07-2023 00:15:26 -0400
Hi, I would be careful to not refresh the base view, if the base view is cached completely without any data loss then you could use base view with only cache so that it doesn't look up to source and refresh data. Using full cache mode will be appropriate to achieve this. To find the deleted rows from the source table, I would create a separate base view of the source table and join it with an already existing base view that is using cache as a data source and return the values that are now missing in the source, using primary key field or any other unique value field if present. Hope this helps.
Denodo Team
10-07-2023 08:04:44 -0400
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