Re: int64/double for time/timestamp - Mailing list pgsql-hackers

From Thomas Hallgren
Subject Re: int64/double for time/timestamp
Date
Msg-id thhal-0AtoQA8PExyc3cTTRuv6pXJu2UUf60M@mailblocks.com
Whole thread Raw
In response to Re: int64/double for time/timestamp  (Teodor Sigaev <teodor@sigaev.ru>)
Responses Re: int64/double for time/timestamp  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
Teodor Sigaev wrote:
>> Urgh.  This is clearly a bug.  All the code in utils/adt seems to be
>> correctly set up to treat TimeADT as an integral value, but then the two
>> macros quoted are converting the value to float8 and back again ... so
>> what's actually on disk is the float8 equivalent of what the int64 value
>> is supposed to be :-(.  As long as the macros are used *consistently* to
>> fetch and store time datums, no one would notice --- you could only see
>> a difference if the int64 values got large enough to not be represented
>> completely accurately as floats, which I believe is impossible for type
>> time.
>>
>> So the fact that you're seeing a bug in btree_gist suggests that
>> someplace you're cheating and bypassing the FooGetDatum/DatumGetFoo
>> macros.
>>
>> We'll obviously want to fix this going forward for efficiency reasons,
>> but it's an initdb-forcer because it'll change the on-disk
>> representation of time columns.  So we can't change it in 8.0 or before.
> 
> 
> So, will we do it? I can do, but I don't know: Is there a place which 
> contains storage version (except file PG_VERSION)?
> 
> 
When making PL/Java dynamically adapt to the setting of 
integer-datetimes, I too was bitten by this bug. Is it safe to assume 
that the fix for this will arrive in 8.1.0?

Regards,
Thomas Hallgren




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