Thread: Questions about octal vs. hex for bytea
Hi, everyone. I've got a client who is planning to upgrade from PostgreSQL 8.3 to 9.0 in the coming weeks. They use a lot of tables with bytea columns. They're worried about the switch from octal to hex formats for bytea data. Based on everything I know and have read, the change is only for external representations, for input and output. Output is now by default in hex, but can be changed with a parameter (bytea_output) that provides backward compatibility. Input can be in either octal or hex, with no changes needed. My client is concerned that the internal representation has changed, and is asking me for a script that will change the representation, in order to save space (since hex occupies less space than octal). I'm not aware of such a need, or even the possibility for this to be done; even if the internal representation has changed, it'll be handled in the upgrade process, and doesn't need to be done with anything external. So I've told them that I don't think that anything is necessary for either input or output, except (perhaps) to set bytea_output in its backward-compatibility mode. But I wanted to check with people here, just to double-check my understanding. Thanks in advance, Reuven -- Reuven M. Lerner -- Web development, consulting, and training Mobile: +972-54-496-8405 * US phone: 847-230-9795 Skype/AIM: reuvenlerner
Reuven M. Lerner <reuven@lerner.co.il> wrote: > So I've told them that I don't think that anything is necessary for > either input or output, except (perhaps) to set bytea_output in its > backward-compatibility mode. But I wanted to check with people here, > just to double-check my understanding. You are right, there is no other problem. I have upgraded a customer's database from 8.3 to 9.0, it was a DRUPAL - database. Only backup & restore and set the bytea_output - Parameter, that's all. Andreas -- Really, I'm not out to destroy Microsoft. That will just be a completely unintentional side effect. (Linus Torvalds) "If I was god, I would recompile penguin with --enable-fly." (unknown) Kaufbach, Saxony, Germany, Europe. N 51.05082°, E 13.56889°
Been using bytea heavily through JDBC. In transitioning to 9.0 I've found the need to set the bytea_output parameter butotherwise everything else works the same as it did before. As for storage space concerns I do not know for sure but the numbers cannot be that substantial to warrant changing an existingdatabase unless large binary processing takes up a significant portion of the processing (as opposed to simple documentstorage and retrieval which is what I am doing). David J. -----Original Message----- From: pgsql-general-owner@postgresql.org [mailto:pgsql-general-owner@postgresql.org] On Behalf Of Reuven M. Lerner Sent: Sunday, February 20, 2011 6:31 AM To: pgsql-general@postgresql.org Subject: [GENERAL] Questions about octal vs. hex for bytea Hi, everyone. I've got a client who is planning to upgrade from PostgreSQL 8.3 to 9.0 in the coming weeks. They use a lotof tables with bytea columns. They're worried about the switch from octal to hex formats for bytea data. Based on everything I know and have read, the change is only for external representations, for input and output. Outputis now by default in hex, but can be changed with a parameter (bytea_output) that provides backward compatibility. Input can be in either octal or hex, with no changes needed. My client is concerned that the internal representation has changed, and is asking me for a script that will change the representation,in order to save space (since hex occupies less space than octal). I'm not aware of such a need, or eventhe possibility for this to be done; even if the internal representation has changed, it'll be handled in the upgradeprocess, and doesn't need to be done with anything external. So I've told them that I don't think that anything is necessary for either input or output, except (perhaps) to set bytea_outputin its backward-compatibility mode. But I wanted to check with people here, just to double-check my understanding. Thanks in advance, Reuven -- Reuven M. Lerner -- Web development, consulting, and training Mobile: +972-54-496-8405 * US phone: 847-230-9795 Skype/AIM: reuvenlerner -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
"Reuven M. Lerner" <reuven@lerner.co.il> Sunday 20 February 2011 12:31:09 > Hi, everyone. I've got a client who is planning to upgrade from > PostgreSQL 8.3 to 9.0 in the coming weeks. They use a lot of tables > with bytea columns. They're worried about the switch from octal to hex > formats for bytea data. > > > Based on everything I know and have read, the change is only for > external representations, for input and output. Output is now by > default in hex, but can be changed with a parameter (bytea_output) that > provides backward compatibility. Input can be in either octal or hex, > with no changes needed. > > > My client is concerned that the internal representation has changed, and > is asking me for a script that will change the representation, in order > to save space (since hex occupies less space than octal). I'm not aware > of such a need, or even the possibility for this to be done; even if the > internal representation has changed, it'll be handled in the upgrade > process, and doesn't need to be done with anything external. > > > So I've told them that I don't think that anything is necessary for > either input or output, except (perhaps) to set bytea_output in its > backward-compatibility mode. But I wanted to check with people here, > just to double-check my understanding. > > > Thanks in advance, > > > Reuven There is no internal change how bytea is keept or at least internally data are not keept in octal or hex represenation. If your client uses JDBC it's better to download newest driver. It should support as well hex and octal receive. It is safer to turn on backward compatibility. I know nothing how pg_dump will work to migrate data. Regards, Radek
"Reuven M. Lerner" <reuven@lerner.co.il> writes:
> My client is concerned that the internal representation has changed, and
> is asking me for a script that will change the representation, in order
> to save space (since hex occupies less space than octal).
This is complete nonsense. The internal representation is just bytes.
regards, tom lane
Thanks, everyone, for the swift and clear responses. It's good to know that I did understand things correctly! Reuven