Re: Incorrect mention of number of columns? - Mailing list pgsql-docs

From Magnus Hagander
Subject Re: Incorrect mention of number of columns?
Date
Msg-id CABUevEwR7-6Ki+mH5zG4nAHMRFEK-GMu--D1qcDaF9yn9+8kVg@mail.gmail.com
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In response to Incorrect mention of number of columns?  ("Daniel Westermann (DWE)" <daniel.westermann@dbi-services.com>)
List pgsql-docs
On Fri, Nov 3, 2023 at 5:09 PM Daniel Westermann (DWE)
<daniel.westermann@dbi-services.com> wrote:
>
> Hi,
>
> from the limits page in the docs: https://www.postgresql.org/docs/current/limits.html
>
> "...but a tuple of 1600 bigint columns would consume 12800 bytes and would therefore not fit inside a heap page".
>
> Creating a table with 1600 bigint columns does work with a 8k blocksize:
>
> $ cat gen_tab.sh
> #!/bin/bash
> AMOUNT_OF_COLS=$1
> DATA_TYPE=$2
> STATEMENT="create table t ( "
> for (( i=1 ; i<${AMOUNT_OF_COLS} ; i++ ));
> do
>   STATEMENT+=" col${i} ${DATA_TYPE},"
> done
> STATEMENT+="col${AMOUNT_OF_COLS} ${DATA_TYPE} );"
> echo ${STATEMENT}
>
> .$ /gen_tab.sh 1600 bigint > a.sql
>
> $ psql -f a.sql
> CREATE TABLE
>
> $ psql -c "\d t"
> ...
>  col1598 | bigint |           |          |
>  col1599 | bigint |           |          |
>  col1600 | bigint |           |          |
>
> Am I missing something?

It will fail when you try to insert data in it.

//Magnus



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