TOAST Fields serialisation/deserialization performance - Mailing list pgsql-performance

From Piyush Katariya
Subject TOAST Fields serialisation/deserialization performance
Date
Msg-id CAA5REoVA06P8Et-wKOjCftUUk6kfStOJWbD2kWaoQs_spdszzg@mail.gmail.com
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Responses Re: TOAST Fields serialisation/deserialization performance  (Laurenz Albe <laurenz.albe@cybertec.at>)
List pgsql-performance
Hello Gents,

I have a few queries regarding the TOAST Fields serialisation/deserialization performance.

The use case i am trying to solve here is to have millions of partitions and aggregate the data in array field.

I wish to know if i declare certain column in table as "array of UDT/JSONB" and enable either lz4 or zstd compression on it, does appending or prepending to that array or even changing the intermediate fields of UDT/JSONB objects. in that array has a runtime cost of full array data de-serialization every single time. If i perform any UPDATE operation on its elements or add/remove new elements from any position, does PG rewrites the new version of the column value regardless of its size.

Let me know if more inputs are required

--
Thanks,
Piyush Katariya

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