Thread: Notes or comments on columns in a table
PostgreSQL 9.2
When creating a table or altering a column of a table, is there a way to add notes on a column?
If not:
I have a new enhancement request. When creating a table or altering a column, it would be nice if a user could add “comments” or “notes” to a column. This note would only appear when doing “\d table_name”.
Why? I was adding a new column to a table called “type”. Normally I only add types as characters even though integers are much better for indexing. The problem with integers is I never remember what value means what. Does a 1 mean directory or file. So I end up creating “type” as a character so I can do a quick SELECT DISTINCT to figure out the options. I would use integers if I could do \d table_name to see in the notes section what values meant. I would think other people run into this issue all the time.
Thanks,
Lance Campbell
Software Architect
Web Services at Public Affairs
217-333-0382
Attachment
Campbell, Lance wrote on 14.02.2013 20:09: > PostgreSQL 9.2 > > When creating a table or altering a column of a table, is there a way > to add notes on a column? > comment on table foo is 'the foo table'; comment on column foo.bar is 'the bar column'; http://www.postgresql.org/docs/current/static/sql-comment.html
PostgreSQL 9.2
When creating a table or altering a column of a table, is there a way to add notes on a column?
If not:
I have a new enhancement request. When creating a table or altering a column, it would be nice if a user could add “comments” or “notes” to a column. This note would only appear when doing “\d table_name”.
Why? I was adding a new column to a table called “type”. Normally I only add types as characters even though integers are much better for indexing. The problem with integers is I never remember what value means what. Does a 1 mean directory or file. So I end up creating “type” as a character so I can do a quick SELECT DISTINCT to figure out the options. I would use integers if I could do \d table_name to see in the notes section what values meant. I would think other people run into this issue all the time.
You should use an enumerated type definition.
create type my_file_type (
'File',
'Directory',
'SymLink')
create table foo (
id integer primary key,
filetype my_file_type
)
insert into foo(1, 'File');
select * from foo;
1 File
... and so forth.
Craig
Attachment
I got it to work! You use the COMMENT in conjunction with \d+. Very nice. PostgreSQL Development Team, Thank you so much for having the COMMENT feature in PostgreSQL. This is great! Thanks, Lance Campbell Software Architect Web Services at Public Affairs 217-333-0382 -----Original Message----- From: pgsql-admin-owner@postgresql.org [mailto:pgsql-admin-owner@postgresql.org] On Behalf Of Thomas Kellerer Sent: Thursday, February 14, 2013 2:10 PM To: pgsql-admin@postgresql.org Subject: Re: [ADMIN] Notes or comments on columns in a table Campbell, Lance wrote on 14.02.2013 20:09: > PostgreSQL 9.2 > > When creating a table or altering a column of a table, is there a way > to add notes on a column? > comment on table foo is 'the foo table'; comment on column foo.bar is 'the bar column'; http://www.postgresql.org/docs/current/static/sql-comment.html -- Sent via pgsql-admin mailing list (pgsql-admin@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-admin
Hello, Could explain somebody what will happen, if the slave server fails ? Will it affect the master functionality/availability ? I'm using simple master-slave replication with 2 servers. -- Best regards
> > Hello, > > Could explain somebody what will happen, if the slave server fails ? > Will it affect the master functionality/availability ? nothing!!! the Master continuo work. ;-))) > I'm using simple master-slave replication with 2 servers. > > > -- > Best regards > > > -- > Sent via pgsql-admin mailing list (pgsql-admin@postgresql.org) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-admin--- > This message was processed by Kaspersky Mail Gateway 5.6.28/RELEASE > running at host imx2.etecsa.cu > Visit our web-site: <http://www.kaspersky.com>, <http://www.viruslist.com> > Saludos, Gilberto Castillo La Habana, Cuba --- This message was processed by Kaspersky Mail Gateway 5.6.28/RELEASE running at host imx3.etecsa.cu Visit our web-site: <http://www.kaspersky.com>, <http://www.viruslist.com>
On 2/20/2013 5:56 PM, Gilberto Castillo wrote:
Hello, Could explain somebody what will happen, if the slave server fails ? Will it affect the master functionality/availability ?nothing!!! the Master continuo work. ;-)))I'm using simple master-slave replication with 2 servers. -- Best regards -- Sent via pgsql-admin mailing list (pgsql-admin@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-admin--- This message was processed by Kaspersky Mail Gateway 5.6.28/RELEASE running at host imx2.etecsa.cu Visit our web-site: <http://www.kaspersky.com>, <http://www.viruslist.com>Saludos, Gilberto Castillo La Habana, Cuba--- This message was processed by Kaspersky Mail Gateway 5.6.28/RELEASE running at host imx3.etecsa.cu Visit our web-site: <http://www.kaspersky.com>, <http://www.viruslist.com>
If it's a slony replication then master continues to work and will catch up when slave is available.
However if the Streaming replication is used, Matser continues to work if slave is unavailable till it finds space for WAL archiving on master, depends on the archieving strategy that implemented while configuring replication. WAL's keep accumulating on the master server till it applies to Slave server after it is available. As long as it find space on master, there is no impact but once it fills all the space, master may go down.
Ook, thanks =)
On 2/20/2013 5:56 PM, Gilberto Castillo wrote:Hello, Could explain somebody what will happen, if the slave server fails ? Will it affect the master functionality/availability ?nothing!!! the Master continuo work. ;-)))I'm using simple master-slave replication with 2 servers. -- Best regards -- Sent via pgsql-admin mailing list (pgsql-admin@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-admin--- This message was processed by Kaspersky Mail Gateway 5.6.28/RELEASE running at host imx2.etecsa.cu Visit our web-site: <http://www.kaspersky.com>, <http://www.viruslist.com>Saludos, Gilberto Castillo La Habana, Cuba--- This message was processed by Kaspersky Mail Gateway 5.6.28/RELEASE running at host imx3.etecsa.cuVisit our web-site: <http://www.kaspersky.com>, <http://www.viruslist.com>
Prashanth Ranjalkar <prashant.ranjalkar@gmail.com> wrote: >> Hello, Could explain somebody what will happen, if the slave > It depends on the type of replication is used. > > If it's a slony replication then master continues to work and > will catch up when slave is available. > > However if the Streaming replication is used, [...] once it fills > all the space, master may go down. That strikes me a false distinction -- Slony also stores data to be replicated until the slave becomes available. Either way you can control where that is stored, and you need to watch out for space problems on an extended outage of a replica. An issue I don't think I've seen mentioned is that if you use synchronous replication you are telling PostgreSQL not to return an indication of success for a data-modifying transaction until the work of that transaction has been persisted on at least one replica. To avoid stalls on the master, you may want to define multiple synchronous replicas, so that when one goes down you keep running without DBA intervention. -- Kevin Grittner EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company