On 12/08/13 17:57, Mark Rotteveel wrote:
> What is the meaning of the blob_id in the response to op_open_blob(2)?
Number of that object at the server site.
> It is not the same as the original blob_id.
Definitely not.
> Is it something that can
> (should?) be ignored?
If we want to work with that blob later ignoring returned by server ID
is very bad idea :-)
>
> The current implementation in Jaybird uses it to replace the current
> blob id in the handle, but that doesn't seem very logical to me.
I do not know details of Jaybird. It's strange for me that blob handle
exists before getting successful reply from server to open blob, but
different implementations may exist.
ID returned by the server is a number of a blob object in the server's
communication port (exactly like each transaction, statement, etc. has
it's ID) and should be used later to ask server to perform some
operation with that blob (like get segment). I.e. it should be stored
somewhere in blob's handle. Where and how - definitely implementation's
defined. This is how it's done in fbclient (I've thrown away some parts
of code to make it better readable):
PACKET* packet = &rdb->rdb_packet;
packet->p_operation = op_open_blob2;
P_BLOB* p_blob = &packet->p_blob;
p_blob->p_blob_transaction = transaction->rtr_id;
p_blob->p_blob_id = *id; // blob id passed by user
send_and_receive(status, rdb, packet);
Rbl* blob = new Rbl;
blob->rbl_rdb = rdb;
blob->rbl_rtr = transaction;
blob->rbl_id = packet->p_resp.p_resp_object; // ID returned
by server
I.e. initial blob id from user never goes into handle at all.
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