From: Dean Gibson (DB Administrator) <postgresql@mailpen.com>
To: pgsql-general@lists.postgresql.org
Subject: Re: AWS forcing PG upgrade from v9.6 a disaster
Date: Fri, 28 May 2021 15:06:10 -0700
Message-ID: <d73e2731-31ba-df14-9b9c-974342200ae8@mailpen.com> (raw)
In-Reply-To: <70edb767-6ba0-1065-2f74-f01440e3caea@gmail.com>
References: <3fa6fd38-1f92-98ab-0055-3e0eb7e4e772@ultimeth.com>
<2a1b34f4-73d4-585b-f4fc-3bd9b9ba248e@aklaver.com>
<88255b75-e7e3-b29c-0e75-f989ea320570@mailpen.com>
<70edb767-6ba0-1065-2f74-f01440e3caea@gmail.com>
On 2021-05-28 12:38, Ron wrote:
> On 5/28/21 1:40 PM, Dean Gibson (DB Administrator) wrote:
>> On 2021-05-28 08:12, Adrian Klaver wrote:
>>> On 5/27/21 8:41 PM, Dean Gibson (DB Administrator) wrote:
>>>> I started to use PostgreSQL v7.3 in 2003 on my home Linux systems
>>>> (4 at one point), gradually moving to v9.0 w/ replication in 2010.
>>>> In 2017 I moved my 20GB database to AWS/RDS, gradually upgrading to
>>>> v9.6, & was entirely satisfied with the result.
>>>>
>>>> In March of this year, AWS announced that v9.6 was nearing end of
>>>> support, & AWS would forcibly upgrade everyone to v12 on January
>>>> 22, 2022, if users did not perform the upgrade earlier. My first
>>>> attempt was successful as far as the upgrade itself, but complex
>>>> queries that normally ran in a couple of seconds on v9.x, were
>>>> taking minutes in v12.
>>>
>>> Did you run a plain
>>> ANALYZE(https://www.postgresql.org/docs/12/sql-analyze.html) on the
>>> tables in the new install?
>>
>> After each upgrade (to 10, 11, 12, & 13), I did a "VACUUM FULL
>> ANALYZE". On 10 through 12, it took about 45 minutes & significant
>> CPU activity, & temporarily doubled the size of the disk space
>> required. As you know, that disk space is not shrinkable under AWS's
>> RDS. On v13, it took 10 hours with limited CPU activity, & actually
>> slightly less disk space required.
>
> Under normal conditions, VACUUM FULL is pointless on a freshly-loaded
> database; in RDS, it's *anti-useful*.
>
> That's why Adrian asked if you did a plain ANALYZE.
Just now did. No change in EXPLAIN ANALYZE output.
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: pgsql-performance@postgresql.org
Cc: postgresql@mailpen.com, pgsql-general@lists.postgresql.org
Subject: Re: AWS forcing PG upgrade from v9.6 a disaster
In-Reply-To: <d73e2731-31ba-df14-9b9c-974342200ae8@mailpen.com>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox