Altering multiple column types

On Fri, Aug 2, 2019 at 7:42 AM Bharanee Rathna <deepfryed@gmail.com> wrote:

Hi,

I'm encountering an issue altering multiple column types in a single ALTER TABLE

psql (12beta2, server 11.4)

it is working on my 11.4 with psql 11.4. Could it be a problem of psql
version 12? Can you try again with a psql "stable"?

testdb=> create table users(id serial primary key, name varchar(255),
age int, email varchar(255));
CREATE TABLE
testdb=> alter table users alter column name type text, alter column
email type text;
ALTER TABLE
testdb=> drop table users;
DROP TABLE
testdb=> create table users(id serial primary key, name varchar(255),
age int, email varchar(255));
CREATE TABLE
testdb=> create index users_email_idx on users(email);
CREATE INDEX
testdb=> alter table users alter column name type text, alter column
email type text;
ALTER TABLE
testdb=> \d users
Table "public.users"
Column | Type | Collation | Nullable | Default
--------+---------+-----------+----------+-----------------------------------
id | integer | | not null | nextval('users_id_seq'::regclass)
name | text | | |
age | integer | | |
email | text | | |
Indexes:
"users_pkey" PRIMARY KEY, btree (id)
"users_email_idx" btree (email)

testdb=> select version();
version
-------------------------------------------------------------------------------------------------------
PostgreSQL 11.4 on x86_64-pc-linux-gnu, compiled by gcc (Ubuntu
8.3.0-6ubuntu1~18.10.1) 8.3.0, 64-bit
(1 row)

On Fri, Aug 2, 2019 at 9:39 AM Bharanee Rathna <deepfryed@gmail.com> wrote:

Hi Luca,

I've tried it with a different client and Postgres 10.9, no luck

psql (10.3, server 10.9)

I've fired up a 12beta2 and it works, either with psql 12 or psql 11.4 on linux.
What if you run the statements within another client (pgadmin, a java
client or something else)?

% psql -U postgres testdb
psql (12beta2)
Type "help" for help.

testdb=# create table users(id serial primary key, name varchar(255),
age int, email varchar(255));
CREATE TABLE
testdb=# create index users_email_idx on users(email);
CREATE INDEX
testdb=# alter table users alter column name type text, alter column
email type text;
ALTER TABLE
testdb=# SELECT version();
version
----------------------------------------------------------------------------------------------------------
PostgreSQL 12beta2 on x86_64-pc-linux-gnu, compiled by gcc (Ubuntu
8.3.0-6ubuntu1~18.10.1) 8.3.0, 64-bit
(1 row)

% ~/git/misc/PostgreSQL/pgenv/pgsql-11.4/bin/psql -U postgres testdb

psql (11.4, server 12beta2)
WARNING: psql major version 11, server major version 12.
Some psql features might not work.
Type "help" for help.

testdb=# drop table users;
DROP TABLE
testdb=# create table users(id serial primary key, name varchar(255),
age int, email varchar(255));
CREATE TABLE
testdb=# create index users_email_idx on users(email);
CREATE INDEX
testdb=# alter table users alter column name type text, alter column
email type text;
ALTER TABLE

Hi Luca,

testing this using docker images. I can replicate it with 10.9-alpine

bash-5.0# psql -h127.0.0.1 -Upostgres test
psql (10.9)
Type "help" for help.

test=# \d users
Table "public.users"
Column | Type | Collation | Nullable |
Default
--------+------------------------+-----------+----------+-----------------------------------
id | integer | | not null |
nextval('users_id_seq'::regclass)
name | character varying(255) | | |
age | integer | | |
email | character varying(255) | | |
Indexes:
"users_pkey" PRIMARY KEY, btree (id)
"users_email_idx" btree (email)
"users_name_idx" btree (name)

test=# alter table users alter column name type text, alter column email
type text;
ERROR: relation "users_name_idx" already exists

test=# select version();
version

---------------------------------------------------------------------------------------
PostgreSQL 10.9 on x86_64-pc-linux-musl, compiled by gcc (Alpine 8.3.0)
8.3.0, 64-bit
(1 row)

and 11.4

psql (11.4)
Type "help" for help.

test=# \d users
Table "public.users"
Column | Type | Collation | Nullable |
Default
--------+------------------------+-----------+----------+-----------------------------------
id | integer | | not null |
nextval('users_id_seq'::regclass)
name | character varying(255) | | |
age | integer | | |
email | character varying(255) | | |
Indexes:
"users_pkey" PRIMARY KEY, btree (id)
"users_email_idx" btree (email)
"users_name_idx" btree (name)

test=# alter table users alter column name type text, alter column email
type text;
ERROR: relation "users_name_idx" already exists

test=# select version();
version

---------------------------------------------------------------------------------------
PostgreSQL 11.4 on x86_64-pc-linux-musl, compiled by gcc (Alpine 8.3.0)
8.3.0, 64-bit
(1 row)

Not sure what's going on at my end ...

On Fri, 2 Aug 2019 at 17:44, Luca Ferrari <fluca1978@gmail.com> wrote:

On Fri, Aug 2, 2019 at 10:06 AM Bharanee Rathna <deepfryed@gmail.com> wrote:

Hi Luca,

testing this using docker images. I can replicate it with 10.9-alpine

bash-5.0# psql -h127.0.0.1 -Upostgres test
psql (10.9)
Type "help" for help.

test=# \d users
Table "public.users"
Column | Type | Collation | Nullable | Default
--------+------------------------+-----------+----------+-----------------------------------
id | integer | | not null | nextval('users_id_seq'::regclass)
name | character varying(255) | | |
age | integer | | |
email | character varying(255) | | |
Indexes:
"users_pkey" PRIMARY KEY, btree (id)
"users_email_idx" btree (email)
"users_name_idx" btree (name)

My fault!
I missed one index, so it is working with one index a two column alter
table, but not with two indexes:

testdb=# alter table users alter column name type text, alter column
email type text;
alter table users alter column name type text, alter column email type text;
psql: ERROR: relation "users_name_idx" already exists

Therefore I think it is a strange behavior, I cannot explain.
I confirm the problem shows up in 11.4 and 12beta2, so I guess there's
must be a reason I don't understand.

Luca

Thanks for confirming, so I know I'm not going crazy :)

FWIW, it works on 10.3 to 10.8 (I think) and looks like a regression.

psql (10.3 (Debian 10.3-2))
Type "help" for help.

test=# create table users(id serial primary key, name varchar(255), email
varchar(255), age int);
CREATE TABLE
Time: 26.650 ms
test=# create index users_name_idx on users(name); create index
users_email_idx on users(email);
CREATE INDEX
Time: 15.660 ms
CREATE INDEX
Time: 12.065 ms
test=# alter table users alter column name type text, alter column email
type text;
ALTER TABLE
Time: 7.213 ms
test=# select version();

version
---------------------------------------------------------------------------------------------------------
PostgreSQL 10.3 (Debian 10.3-2) on x86_64-pc-linux-gnu, compiled by gcc
(Debian 7.3.0-11) 7.3.0, 64-bit
(1 row)

Time: 2.683 ms

Bharanee Rathna <deepfryed@gmail.com> writes:

I'm encountering an issue altering multiple column types in a single ALTER
TABLE

Yeah, this is a regression in the May batch of minor releases :-(.
It's fixed for next week's releases.

https://git.postgresql.org/gitweb/?p=postgresql.git&amp;a=commitdiff&amp;h=f946a4091

regards, tom lane

Thanks Tom!