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Re: [HACKERS] pg_upgrade failed with error - ERROR: column "a" in child table must be marked NOT NULL

Amit Langote <langote_amit_f8@lab.ntt.co.jp>

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From: Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>
To: Ali Akbar <the.apaan@gmail.com>, Michael Paquier <michael.paquier@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, tushar <tushar.ahuja@enterprisedb.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2017-12-13T01:41:24Z
Lists: pgsql-hackers 
Hi.

On 2017/12/13 9:22, Ali Akbar wrote:
> For me, it's better to prevent that from happening. So, attempts to
> DROP NOT NULL on the child must be rejected. The attached patch does
> that.
> 
> Unfortunately, pg_class has no "has_parent" attribute, so in this
> patch, it hits pg_inherits everytime DROP NOT NULL is attempted.
> 
> Notes:
> - It looks like we could remove the parent partition checking above?
> Because the new check already covers what it does

I noticed that too.

So, if we're going to prevent DROP NOT NULL on *all* child table (not just
partitions), we don't need the code that now sits there to prevent that
only for partitions.

Minor comments on the patch:

+	/* If rel has parents, shoudn't drop NOT NULL if parent has the same */

How about: ".. if some parent has the same"

+		heap_close(parent, AccessShareLock);

Maybe, we shouldn't be dropping the lock so soon.

Thanks,
Amit

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Fix new pg_upgrade query not to rely on regnamespace

  2. pg_upgrade: check for inconsistencies in not-null constraints w/inheritance

  3. Apply ALTER ... SET NOT NULL recursively in ALTER ... ADD PRIMARY KEY.