Horton

Thread

  1. Re: [HACKERS] Re: [BUGS] uniqueness not always correct

    Tom Lane <tgl@sss.pgh.pa.us> — 1999-11-11T16:57:59Z

    Vadim Mikheev <vadim@krs.ru> writes:
> Yes, I reproduced this (Solaris 2.5/sparc). 
> Seems like CIDR problem(??!):

Yes.  Looks like the low-order bits of a CIDR address are garbage,
but network_cmp() compares them as though all bits are significant.
So, indeed, it may think two different instances of '1.2.3/24'
are not equal.

The regular inet comparison functions at least *try* to mask out
garbage bits, but I think they get it wrong too --- they should be
taking the smaller of ip_bits(a1) and ip_bits(a2) as the number of
bits to compare.  They don't.  Thus, for example,

regression=> select '1.2.5/16'::cidr < '1.2.3/24'::cidr;
?column?
--------
f
(1 row)

which looks wrong to me.

In short, it's a bug in the inet data types, not a generic problem
with unique indexes.

			regards, tom lane

  2. Re: [HACKERS] Re: [BUGS] uniqueness not always correct

    Bruce Momjian <pgman@candle.pha.pa.us> — 1999-12-16T01:42:32Z

    Never mind.  Patch is fir mac, not inet.

> Vadim Mikheev <vadim@krs.ru> writes:
> > Yes, I reproduced this (Solaris 2.5/sparc). 
> > Seems like CIDR problem(??!):
> 
> Yes.  Looks like the low-order bits of a CIDR address are garbage,
> but network_cmp() compares them as though all bits are significant.
> So, indeed, it may think two different instances of '1.2.3/24'
> are not equal.
> 
> The regular inet comparison functions at least *try* to mask out
> garbage bits, but I think they get it wrong too --- they should be
> taking the smaller of ip_bits(a1) and ip_bits(a2) as the number of
> bits to compare.  They don't.  Thus, for example,
> 
> regression=> select '1.2.5/16'::cidr < '1.2.3/24'::cidr;
> ?column?
> --------
> f
> (1 row)
> 
> which looks wrong to me.
> 
> In short, it's a bug in the inet data types, not a generic problem
> with unique indexes.
> 
> 			regards, tom lane
> 
> ************
> 


-- 
  Bruce Momjian                        |  http://www.op.net/~candle
  maillist@candle.pha.pa.us            |  (610) 853-3000
  +  If your life is a hard drive,     |  830 Blythe Avenue
  +  Christ can be your backup.        |  Drexel Hill, Pennsylvania 19026

  3. Re: [HACKERS] Re: [BUGS] uniqueness not always correct

    Bruce Momjian <pgman@candle.pha.pa.us> — 2000-03-07T22:50:57Z

    I have just applied a user patch to fix this reported problem.


> Vadim Mikheev <vadim@krs.ru> writes:
> > Yes, I reproduced this (Solaris 2.5/sparc). 
> > Seems like CIDR problem(??!):
> 
> Yes.  Looks like the low-order bits of a CIDR address are garbage,
> but network_cmp() compares them as though all bits are significant.
> So, indeed, it may think two different instances of '1.2.3/24'
> are not equal.
> 
> The regular inet comparison functions at least *try* to mask out
> garbage bits, but I think they get it wrong too --- they should be
> taking the smaller of ip_bits(a1) and ip_bits(a2) as the number of
> bits to compare.  They don't.  Thus, for example,
> 
> regression=> select '1.2.5/16'::cidr < '1.2.3/24'::cidr;
> ?column?
> --------
> f
> (1 row)
> 
> which looks wrong to me.
> 
> In short, it's a bug in the inet data types, not a generic problem
> with unique indexes.
> 
> 			regards, tom lane
> 
> ************
> 


-- 
  Bruce Momjian                        |  http://www.op.net/~candle
  pgman@candle.pha.pa.us               |  (610) 853-3000
  +  If your life is a hard drive,     |  830 Blythe Avenue
  +  Christ can be your backup.        |  Drexel Hill, Pennsylvania 19026

  4. Re: [HACKERS] Re: [BUGS] uniqueness not always correct

    Tom Lane <tgl@sss.pgh.pa.us> — 2000-03-07T23:22:04Z

    Bruce Momjian <pgman@candle.pha.pa.us> writes:
> I have just applied a user patch to fix this reported problem.

If you had read the followup, you would have seen that I have doubts
about this patch, and in fact Ryan acknowledges that it probably doesn't
do the right thing for INET.  I think there is more work to do here.

			regards, tom lane

  5. Re: [HACKERS] Re: [BUGS] uniqueness not always correct

    Bruce Momjian <pgman@candle.pha.pa.us> — 2000-03-08T01:44:21Z

    > Bruce Momjian <pgman@candle.pha.pa.us> writes:
> > I have just applied a user patch to fix this reported problem.
> 
> If you had read the followup, you would have seen that I have doubts
> about this patch, and in fact Ryan acknowledges that it probably doesn't
> do the right thing for INET.  I think there is more work to do here.

Reversed out.

"I never met a patch I didn't like."  :-)

-- 
  Bruce Momjian                        |  http://www.op.net/~candle
  pgman@candle.pha.pa.us               |  (610) 853-3000
  +  If your life is a hard drive,     |  830 Blythe Avenue
  +  Christ can be your backup.        |  Drexel Hill, Pennsylvania 19026