Byte Sizes
От | Pierre-Frédéric Caillaud |
---|---|
Тема | Byte Sizes |
Дата | |
Msg-id | opsd18wll2cq72hf@musicbox обсуждение исходный текст |
Ответ на | Re: [JDBC] ERROR: canceling query due to user request (Paul Thomas <paul@tmsl.demon.co.uk>) |
Список | pgsql-general |
Hello, * On the size of arrays : I did not find any info in the Docs on this. How many bytes does an array take on disk ? My bet would be 4 bytes for number of dimensions, 4 per dimension for the length, and then the storage requirements of whatever's in the array. If the array contains fixed size elements like integers, it'd be 4 bytes per element. However if it contains variable length elements like text, is there a pointer table ? Or are the elements packed together ? Is there any advantage in using a smallint[] over an integer[] ? Does a smallint[] with 2 elements really take 12 bytes ? * On Alignment : The docs say fields are aligned on 4-bytes boundaries. Does this mean that several consecutive smallint fields will take 4 bytes each ? What about seleral consecutive "char" fields ? I ask this because I'll have a lot of columns with small values to store in a table, and would like it to be small and to fit in the cache. Thanks for any info.
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