Re: WAL logging problem in 9.4.3?

On Thu, Sep 29, 2016 at 10:02 PM, Kyotaro HORIGUCHI
<horiguchi(dot)kyotaro(at)lab(dot)ntt(dot)co(dot)jp> wrote:
> Hello,
>
> At Thu, 29 Sep 2016 16:59:55 +0900, Michael Paquier <michael(dot)paquier(at)gmail(dot)com> wrote in <CAB7nPqT5x05tG7aut1yz+WJN76DqNz1Jzq46fSFtee4YbY0YcA(at)mail(dot)gmail(dot)com>
>> On Mon, Sep 26, 2016 at 5:03 PM, Kyotaro HORIGUCHI
>> <horiguchi(dot)kyotaro(at)lab(dot)ntt(dot)co(dot)jp> wrote:
>> > Hello, I return to this before my things:)
>> >
>> > Though I haven't played with the patch yet..
>>
>> Be sure to run the test cases in the patch or base your tests on them then!
>
> All items of 006_truncate_opt fail on ed0b228 and they are fixed
> with the patch.
>
>> > Though I don't know how it actually impacts the perfomance, it
>> > seems to me that we can live with truncated_to and sync_above in
>> > RelationData and BufferNeedsWAL(rel, buf) instead of
>> > HeapNeedsWAL(rel, buf). Anyway up to one entry for one relation
>> > seems to exist at once in the hash.
>>
>> TBH, I still think that the design of this patch as proposed is pretty
>> cool and easy to follow.
>
> It is clean from certain viewpoint but additional hash,
> especially hash-searching on every HeapNeedsWAL seems to me to be
> unacceptable. Do you see it accetable?
>
>
> The attached patch is quiiiccck-and-dirty-hack of Michael's patch
> just as a PoC of my proposal quoted above. This also passes the
> 006 test. The major changes are the following.
>
> - Moved sync_above and truncted_to into RelationData.
>
> - Cleaning up is done in AtEOXact_cleanup instead of explicit
> calling to smgrDoPendingSyncs().
>
> * BufferNeedsWAL (replace of HeapNeedsWAL) no longer requires
> hash_search. It just refers to the additional members in the
> given Relation.
>
> X I feel that I have dropped one of the features of the origitnal
> patch during the hack, but I don't recall it clearly now:(
>
> X I haven't consider relfilenode replacement, which didn't matter
> for the original patch. (but there's few places to consider).
>
> What do you think about this?

I have moved this patch to next CF. (I still need to look at your patch.)
--
Michael