Re: [PDO] LOBs in pgsql

On 09.07.2008, at 05:20, Jeremy wrote:

Looking through the pdo_pgsql code, I can see why this is: it makes a decision about LOB handling based on whether you are using the "distant" (or oid) method, or the bytea column method. If you are using the former, it uses the appropriate functions to open a stream resource to the object and all is good. However, if you are using the latter, it tries to allocate memory for the entire lob and unescape it all at once. Obviously, this fails miserably in my case, or I wouldn't be posting here :-) I could increase the memory_limit to be larger than a LOB will ever be. But what if this were gigabytes? Am I tied to the "distant" method, which is not particularly relational and ignores all concept of permissions? I feel like the behavior should be able to be overridden in the driver options or some such, but there is obviously no way to do that. The true LOB (using the distant method) functions use the lo_* functions from libpq behind the scenes, so obviously this is not possible with bytea fields. However, there must be some way to use a buffered reader to avoid over-allocation here.

Its my understanding that this is simply the fault of PostgreSQL at this point, since they have not provided a streaming API for bytea. The only way to do it would be for us to emulate it, which I think is probably not a high priority given the general lack of ressources around PDO. So unless you want to step up and do this .. regards, Lukas Kahwe Smith mls@pooteeweet.org