Robert Haas wrote: > Part of my hesitancy, I suppose, is that I don't > understand why we even have this strange convention of making \. > terminate the input in the first place -- I mean, why wouldn't that be > done in some kind of out-of-band way, rather than including a special > marker in the data?
The v3 protocol added the out-of-band method, but the v2 protocol did not have it, and as far as I understand, this is the reason why CopyReadLineText() must interpret \. as an end-of-data marker. The v2 protocol was removed in pg14 https://www.postgresql.org/docs/release/14.0/ <quote> Remove server and libpq support for the version 2 wire protocol (Heikki Linnakangas) This was last used as the default in PostgreSQL 7.3 (released in 2002). </quote> Also I hadnt' noticed this before, but the current doc has this mention that is relevant to this patch: https://www.postgresql.org/docs/current/protocol-changes.html "Summary of Changes since Protocol 2.0" <quote> COPY data is now encapsulated into CopyData and CopyDone messages. There is a well-defined way to recover from errors during COPY. The special “\.” last line is not needed anymore, and is not sent during COPY OUT. (It is still recognized as a terminator during COPY IN, but its use is deprecated and will eventually be removed.) </quote> What the present patch does is essentially, for the server-side part, stop recognizing "\." as as terminator, like this paragraph says, but it does that for CSV only, not for TEXT. > Hmm. Looking at the rest of the patch, it seems like you're removing > the logic that prevents us from interpreting > > \. lksdghksdhgjskdghjs > > as an end-of-file while in CSV mode. But I would have thought based on > what problem you're trying to fix that you would have wanted to keep > that logic and further restrict it so that it only applies when not > within a quoted string. > > Maybe I'm misunderstanding what bug you're trying to fix? The fix is that \. is no longer recognized as special in CSV, whether alone on a line or not, and whether in a quoted section or not. It's always interpreted as data, like it would have been in the first place, I imagine, if the v2 protocol could have handled it. This is why the patch consists mostly of removing code and simplifying comments. Best regards, -- Daniel Vérité https://postgresql.verite.pro/ Twitter: @DanielVerite
