public inbox for [email protected]  

help / color / mirror / Atom feed

From: Andrey M. Borodin <[email protected]>
To: Alexander Lakhin <[email protected]>
Cc: Michael Zhilin <[email protected]>
Cc: [email protected]
Cc: y sokolov <[email protected]>
Subject: Re: [BUG] false positive in bt_index_check in case of short 4B varlena datum
Date: Mon, 8 Jan 2024 19:34:41 +0500
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
References: <[email protected]>
	<[email protected]>
	<[email protected]>

Hi Alexander!

I think both cases are very interesting and deserve two separate bug items.

> On 14 Dec 2023, at 22:17, Alexander Lakhin <[email protected]> wrote:
> 
> 
> By changing the storage mode for a column, you can also get another error:
> CREATE TABLE t(f1 text);
> CREATE INDEX t_idx ON t(f1);
> INSERT INTO t VALUES(repeat('1234567890', 1000));
> ALTER TABLE t ALTER COLUMN f1 SET STORAGE plain;
> 
> CREATE EXTENSION amcheck;
> SELECT bt_index_check('t_idx', true);
> 
> ERROR:  index row requires 10016 bytes, maximum size is 8191
> 

I think In this case we should warn user that index contains tuples with datums that are not insertable anymore. And abort heapallindexed.


> On 8 Jan 2024, at 00:00, Alexander Lakhin <[email protected]> wrote:
> 
> What is your opinion regarding similar failures, which are not addressed
> by the patch? Besides the case shown above, there is another one:
> CREATE TABLE tbl(i int4, t text);
> ALTER TABLE tbl ALTER COLUMN t SET STORAGE plain;
> CREATE INDEX tbl_idx ON tbl (t, i) WITH (fillfactor = 10);
> INSERT INTO tbl SELECT g, repeat('Test', 250) FROM generate_series(1, 130) g;
> ALTER TABLE tbl ALTER COLUMN t SET STORAGE extended;
> 
> CREATE EXTENSION amcheck;
> SELECT bt_index_check('tbl_idx', true);
> 
> ERROR:  heap tuple (0,1) from table "tbl" lacks matching index tuple within index "tbl_idx"
> HINT:  Retrying verification using the function bt_index_parent_check() might provide a more specific error.

IMO In this case we should handle VARATT_IS_EXTENDED in bt_normalize_tuple().

BTW CI fails of the original patch ITT are related to the fact that COPY in\out file is created in PG_ABS_SRCDIR instead of PG_ABS_BUILDDIR. In an off-list conversation I recommended Michael to mimic tests regress/largeobject.sql. Though, there might be better ideas.

Thanks!


Best regards, Andrey Borodin.

reply

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: [email protected]
  Cc: [email protected], [email protected], [email protected], [email protected]
  Subject: Re: [BUG] false positive in bt_index_check in case of short 4B varlena datum
  In-Reply-To: <[email protected]>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox