Re: build multiple indexes in single table pass?

Aidan Van Dyk wrote:
> * Andrew Dunstan <andrew@dunslane.net> [080401 08:22]:
>   
>> From the "idle thoughts in the middle of the night" department:
>>
>> I don't know if this has come up before exactly, but is it possible that 
>> we could get a performance gain from building multiple indexes from a 
>> single sequential pass over the base table? If so, that would probably 
>> give us  a potential performance improvement in pg_restore quite apart 
>> from the projected improvement to be got from running several steps in 
>> parallel processes. The grammar might look a bit ugly, but I'm sure we 
>> could finesse that.
>>     
>
> I've not looked at any of the code, but would the "synchronized scans"
> heap machinery help the multiple index creations walk the heap together,
> basically giving you this for free (as long as you start concurrent
> index creation)?
>
>
>   

Good question. Might it also help in that case to have pg_dump output 
indexes in a given schema sorted by <tablename, indexname> rather than 
just <indexname>?

cheers

andrew