Re: [GENERAL] Limit on multi-field indexes?

> > > Am I correct in believing that there is a limit of seven columns in a
> > > multi-filed index?
> > >
> > > If so, is it possible to increase this limit (to at least eight) ?
> > >
> > > Cheers and thanks,
> >
> > Not easily.  The columns are stored in an int28 column, that holds 8
> > two-byte integer.  We would have to change that to a larger field.  Very
> > few people have asked for this.
> >
> Getting desperate here.
>
> If it holds 8 integers, why can't I have 8 columns in a multi-field index?
>
> I am currently writing a tool to replicate any database to a PostgreSQL mirror
> and the very first customer for this tool has several tables with 8 fields in
> their primary key. Sod's Law:-((

There is no field in pg_index to determine the number of fields in the
index, so it scans pg_index.indkey until it hits a 0.  Now, I suppose we
could change the code so it goes through indkey until it gets a 0, or
reaches the eighth entry.

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