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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