Horton

Re: new heapcheck contrib module

Peter Geoghegan <pg@bowt.ie>

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From: Peter Geoghegan <pg@bowt.ie>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Mark Dilger <mark.dilger@enterprisedb.com>, Amul Sul <sulamul@gmail.com>, Dilip Kumar <dilipbalaut@gmail.com>, Andres Freund <andres@anarazel.de>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2020-09-22T23:18:51Z
Lists: pgsql-hackers 
On Mon, Sep 21, 2020 at 2:09 PM Robert Haas <robertmhaas@gmail.com> wrote:
> +REVOKE ALL ON FUNCTION
> +verify_heapam(regclass, boolean, boolean, cstring, bigint, bigint)
> +FROM PUBLIC;
>
> This too.

Do we really want to use a cstring as an enum-like argument?

I think that I see a bug at this point in check_tuple() (in
v15-0001-Adding-function-verify_heapam-to-amcheck-module.patch):

> +   /* If xmax is a multixact, it should be within valid range */
> +   xmax = HeapTupleHeaderGetRawXmax(ctx->tuphdr);
> +   if ((infomask & HEAP_XMAX_IS_MULTI) && !mxid_valid_in_rel(xmax, ctx))
> +   {

*** SNIP ***

> +   }
> +
> +   /* If xmax is normal, it should be within valid range */
> +   if (TransactionIdIsNormal(xmax))
> +   {

Why should it be okay to call TransactionIdIsNormal(xmax) at this
point? It isn't certain that xmax is an XID at all (could be a
MultiXactId, since you called HeapTupleHeaderGetRawXmax() to get the
value in the first place). Don't you need to check "(infomask &
HEAP_XMAX_IS_MULTI) == 0" here?

This does look like it's shaping up. Thanks for working on it, Mark.

-- 
Peter Geoghegan

Commits

  1. Add pg_amcheck, a CLI for contrib/amcheck.

  2. Refactor and generalize the ParallelSlot machinery.

  3. Generalize parallel slot result handling.

  4. Move some code from src/bin/scripts to src/fe_utils to permit reuse.

  5. Factor pattern-construction logic out of processSQLNamePattern.

  6. Doc: clean up verify_heapam() documentation.

  7. Fix more portability issues in new amcheck code.

  8. Fix portability issues in new amcheck test.

  9. Try to avoid a compiler warning about using fxid uninitialized.

  10. Extend amcheck to check heap pages.

  11. Adjust walsender usage of xlogreader, simplify APIs

  12. Improve checking of child pages in contrib/amcheck.

  13. Sanitize line pointers within contrib/amcheck.

  14. Fix possible sorting error when aborting use of abbreviated keys.