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From Zhenya Stanilovsky <arzamas...@mail.ru.INVALID>
Subject Re: Update of the default inline size for variable types
Date Wed, 19 Aug 2020 06:22:38 GMT


>Hi guys,
 
Evgeniy, hola!
>
>Currently if a varlength type (such as String or byte[]) is encountered in
>the composite index inline size just defaults to 10, which is almost always
>not enough. I am going to change this and implement following changes:
>
>1) For a column of the variable length keep using 10 as the default size in
>case of the one-column index. But if the index is composite the default
>index size will be calculated as the sum of sizes of all indexed columns.
>For example, for the index like (INT, VARCHAR, VARCHAR, INT) default inline
>size will be 5 + 10 + 10 + 5 = 30 (5 for each int, 10 for each string).
 
Why exactly this approach ? Why not 5 + 10 and its all here ? Do you have some logical base,
statistical distribution or something near it, for now this look as your own decision and
nothing more, i`m wrong ?
>
>2) For sql varchar and binary columns with defined length (for example
>VARCHAR(XX)) use XX + 3 as default inline size for the column (need 3 extra
>bytes for the inner representation of the type).
 
The same question here, why you want o cover all varchar len ? do you compare with other vendors
approach ?
>
>3) Maximum default index size still will be limited by
>IGNITE_MAX_INDEX_PAYLOAD_SIZE, but its default value will be increased to
>64. For example for the index (VARCHAR, VARCHAR, VARCHAR, VARCHAR, VARCHAR,
>VARCHAR, VARCHAR) default index size will be only 64. Same for the columns
>with defined length: by default VARCHAR(100) column will create index only
>with size equal to 64.
>
>Please tell if you have any concerns. Update can be found at
>https://github.com/apache/ignite/pull/8161
>
>Best regards,
>Evgeniy
>  
 
 
 
 
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