Re: custom function for converting human readable sizes to bytes

On Tue, Dec 22, 2015 at 12:11 AM, Robert Haas <robertmhaas@gmail.com> wrote:
> On Sun, Dec 20, 2015 at 4:54 AM, Pavel Stehule <pavel.stehule@gmail.com> wrote:
>> new update:
>>
>> 1. unit searching is case insensitive
>>
>> 2. initial support for binary byte prefixes - KiB, MiB, ..  (IEC standard),
>> change behave for SI units
>>
>> Second point is much more complex then it is looking - if pg_size_bytes
>> should be consistent with pg_size_pretty.
>>
>> The current pg_size_pretty and transformations in guc.c are based on JEDEC
>> standard. Using this standard for GUC has sense - using it for object sizes
>> is probably unhappy.
>>
>> I tried to fix (and enhance) pg_size_pretty - now reports correct units, and
>> via second parameter it allows to specify base: 2 (binary, IEC  - default)
>> or 10 (SI).
>
> -1 from me.  I don't think we should muck with the way pg_size_pretty works.

Yeah.

+ static const unit_multiplier unit_multiplier_table[] =
+ {
+     {"B", 1L},
+     {"kiB", 1024L},
+     {"MiB", 1024L * 1024},
+     {"GiB", 1024L * 1024 * 1024},
+     {"TiB", 1024L * 1024 * 1024 * 1024},
+     {"PiB", 1024L * 1024 * 1024 * 1024 * 1024},
This is rather close to memory_unit_conversion_table in guc.c. Would
it be worth refactoring those unit tables into something more generic
instead of duplicating them?
-- 
Michael