Re: WIP Patch: Selective binary conversion of CSV file foreign tables

Hi Kaigai-san,

> -----Original Message-----
> From: Kohei KaiGai [mailto:kaigai(at)kaigai(dot)gr(dot)jp]
> Sent: Monday, June 25, 2012 9:49 PM
> To: Etsuro Fujita
> Cc: Robert Haas; pgsql-hackers(at)postgresql(dot)org
> Subject: Re: [HACKERS] WIP Patch: Selective binary conversion of CSV file
> foreign tables
>
> Fujita-san,
>
> The revised patch is almost good for me.
> Only point I noticed is the check for redundant or duplicated options I
pointed
> out on the previous post.
> So, if you agree with the attached patch, I'd like to hand over this patch for
> committers.

OK I agree with you. Thanks for the revision!

Besides the revision, I modified check_selective_binary_conversion() to run
heap_close() in the whole-row-reference case. Attached is an updated version of
the patch.

Thanks.

Best regards,
Etsuro Fujita

> All I changed is:
> --- a/src/backend/commands/copy.c
> +++ b/src/backend/commands/copy.c
> @@ -122,6 +122,11 @@ typedef struct CopyStateData @@ -217,7 +221,7 @@ index
> 98bcb2f..0143d81 100644
> }
> + else if (strcmp(defel->defname, "convert_binary") == 0)
> + {
> -+ if (cstate->convert_binary)
> ++ if (cstate->convert_selectively)
> + ereport(ERROR,
> + (errcode(ERRCODE_SYNTAX_ERROR),
> + errmsg("conflicting or redundant options")));
>
> Thanks,
>
> 2012/6/20 Etsuro Fujita <fujita(dot)etsuro(at)lab(dot)ntt(dot)co(dot)jp>:
> > Hi KaiGai-san,
> >
> > Thank you for the review.
> >
> >> -----Original Message-----
> >> From: pgsql-hackers-owner(at)postgresql(dot)org
> >> [mailto:pgsql-hackers-owner(at)postgresql(dot)org] On Behalf Of Kohei KaiGai
> >> Sent: Wednesday, June 20, 2012 1:26 AM
> >> To: Etsuro Fujita
> >> Cc: Robert Haas; pgsql-hackers(at)postgresql(dot)org
> >> Subject: Re: [HACKERS] WIP Patch: Selective binary conversion of CSV
> >> file foreign tables
> >>
> >> Hi Fujita-san,
> >>
> >> Could you rebase this patch towards the latest tree?
> >> It was unavailable to apply the patch cleanly.
> >
> > Sorry, I updated the patch.  Please find attached an updated version
> > of the patch.
> >
> >> I looked over the patch, then noticed a few points.
> >>
> >> At ProcessCopyOptions(), defel->arg can be NIL, isn't it?
> >> If so, cstate->convert_binary is not a suitable flag to check
> >> redundant option. It seems to me cstate->convert_selectively is more
> >> suitable flag to check it.
> >>
> >> +       else if (strcmp(defel->defname, "convert_binary") == 0)
> >> +       {
> >> +           if (cstate->convert_binary)
> >> +               ereport(ERROR,
> >> +                       (errcode(ERRCODE_SYNTAX_ERROR),
> >> +                        errmsg("conflicting or redundant
> >> + options")));
> >> +           cstate->convert_selectively = true;
> >> +           if (defel->arg == NULL || IsA(defel->arg, List))
> >> +               cstate->convert_binary = (List *) defel->arg;
> >> +           else
> >> +               ereport(ERROR,
> >> +                       (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
> >> +                        errmsg("argument to option \"%s\" must be a
> >> list of column names",
> >> +                               defel->defname)));
> >> +       }
> >
> > Yes, defel->arg can be NIL.  defel->arg is a List structure listing
> > all the columns needed to be converted to binary representation, which
> > is NIL for the case where no columns are needed to be converted.  For
> > example,
> > defel->arg is NIL for SELECT COUNT(*).  In this case, while
> > cstate->convert_selectively is set to true, no columns are converted
> > cstate->at
> > NextCopyFrom().  Most efficient case!  In short,
> > cstate->convert_selectively represents whether to do selective binary
> > conversion at NextCopyFrom(), and
> > cstate->convert_binary represents all the columns to be converted at
> > NextCopyFrom(), that can be NIL.
> >
> >> At NextCopyFrom(), this routine computes default values if configured.
> >> In case when these values are not referenced, it might be possible to
> >> skip unnecessary calculations.
> >> Is it unavailable to add logic to avoid to construct cstate->defmap
> >> on unreferenced columns at  BeginCopyFrom()?
> >
> > I think that we don't need to add the above logic because file_fdw
> > does
> > BeginCopyFrom() with attnamelist = NIL, in which case, BeginCopyFrom()
> > doesn't construct cstate->defmap at all.
> >
> > I fixed a bug plus some minor optimization in
> > check_binary_conversion() that is renamed to
> > check_selective_binary_conversion() in the updated version, and now
> > file_fdw gives up selective binary conversion for the following
> > cases:
> >
> >  a) BINARY format
> >  b) CSV/TEXT format and whole row reference
> >  c) CSV/TEXT format and all the user attributes needed
> >
> >
> > Best regards,
> > Etsuro Fujita
> >
> >> Thanks,
> >>
> >> 2012/5/11 Etsuro Fujita <fujita(dot)etsuro(at)lab(dot)ntt(dot)co(dot)jp>:
> >> >> -----Original Message-----
> >> >> From: Robert Haas [mailto:robertmhaas(at)gmail(dot)com]
> >> >> Sent: Friday, May 11, 2012 1:36 AM
> >> >> To: Etsuro Fujita
> >> >> Cc: pgsql-hackers(at)postgresql(dot)org
> >> >> Subject: Re: [HACKERS] WIP Patch: Selective binary conversion of
> >> >> CSV file foreign tables
> >> >>
> >> >> On Tue, May 8, 2012 at 7:26 AM, Etsuro Fujita
> >> > <fujita(dot)etsuro(at)lab(dot)ntt(dot)co(dot)jp>
> >> >> wrote:
> >> >> > I would like to propose to improve parsing efficiency of
> >> >> > contrib/file_fdw by selective parsing proposed by Alagiannis et
> >> >> > al.[1], which means that for a CSV/TEXT file foreign table,
> >> >> > file_fdw performs binary conversion only for the columns needed
> >> >> > for query processing.  Attached is a WIP patch implementing the
feature.
> >> >>
> >> >> Can you add this to the next CommitFest?  Looks interesting.
> >> >
> >> > Done.
> >> >
> >> > Best regards,
> >> > Etsuro Fujita
> >> >
> >> >> --
> >> >> Robert Haas
> >> >> EnterpriseDB: http://www.enterprisedb.com The Enterprise
> >> >> PostgreSQL Company
> >> >>
> >> >
> >> >
> >> >
> >> > --
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> >>
> >>
> >>
> >> --
> >> KaiGai Kohei <kaigai(at)kaigai(dot)gr(dot)jp>
> >>
> >> --
> >> Sent via pgsql-hackers mailing list (pgsql-hackers(at)postgresql(dot)org) To
> >> make changes to your subscription:
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> >>
> >
> >
> >
> >
>
>
>
> --
> KaiGai Kohei <kaigai(at)kaigai(dot)gr(dot)jp>