Re: GiST insert algorithm rewrite

On 01.12.2010 04:10, Robert Haas wrote:
> On Tue, Nov 30, 2010 at 10:26 AM, Heikki Linnakangas
> <heikki.linnakangas@enterprisedb.com>  wrote:
>>> Does the current code cope with the corruption?
>>
>> It's not corruption, but "intended degradation". Yes, the current code copes
>> with it, that's how GiST survives a crash. However, even with the current
>> code, VACUUM will nag if it finds any invalid tuples with this message:
>>
>> ereport(NOTICE,
>>         (errmsg("index \"%s\" needs VACUUM FULL or REINDEX to finish crash
>> recovery",
>>
>> That's harmless, in the sense that all scans and inserts work fine, but
>> scans might need to do more work than if the invalid tuple wasn't there.
>>
>> I don't think we need to go out of our way to support such degraded indexes
>> in 9.1. If you see such notices in your logs, you should REINDEX anyway,
>> before of after pg_upgrade. Let's just make sure that you get a reasonable
>> error message in 9.1 if a scan or insert encounters such a tuple.
>
> I just don't want to take a risk of giving people unexpected wrong
> answers.  It's not clear to me whether that's a risk here or not.

You'll get an error if a scan encounters an invalid tuple.

In the patch I posted, I just ripped out everything related to invalid 
tuples altogether. But we should add a check and ereport for that before 
commit.

--   Heikki Linnakangas  EnterpriseDB   http://www.enterprisedb.com