Re: Automatic free space map filling - Mailing list pgsql-hackers

From Christopher Browne
Subject Re: Automatic free space map filling
Date
Msg-id 871wxiq5s4.fsf@wolfe.cbbrowne.com
Whole thread Raw
In response to Re: Automatic free space map filling  ("Zeugswetter Andreas DCP SD" <ZeugswetterA@spardat.at>)
List pgsql-hackers
Centuries ago, Nostradamus foresaw when ZeugswetterA@spardat.at ("Zeugswetter Andreas DCP SD") would write:
>> > But what about index clearing?  When do you scan each index?
>> 
>> At the end of each iteration (or earlier, depending on 
>> maintenance_work_mem).  So for each iteration you would need 
>> to scan the indexes.
>> 
>> Maybe we could make maintenance_work_mem be the deciding 
>> factor; after scanning the indexes, do the release/reacquire 
>> locks cycle.
>
> But you could do the indexes first and remember how far you can 
> vacuum the heap later.

But the indexes _can't_ be done first; you _first_ need to know which
tuples are dead, which requires looking at the table itself.
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