query large amount of data in c++ using libpq

Started by Felix Jiover 18 years ago2 messagesgeneral
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#1Felix Ji
list@zflier.com

Hi all,
i am using PQexecParams() to "SELECT" about 3 million record in C++, and it
takes several minutes to make it done with used memory dramatically
incresed(about 200MB).
it seems when i using PQexecParams(), i can't use the query result before
all the data is sent to client.
is there something like server side cursor in libpq?
or is there any other way to do this in c++?
some articles say that query for large amount of data is automaticall
handled well by pg, but i can't see how.

thanks~~~~

#2Henrik Zagerholm
henke@mac.se
In reply to: Felix Ji (#1)
Re: query large amount of data in c++ using libpq

19 aug 2007 kl. 06:34 skrev Felix Ji:

Hi all,
i am using PQexecParams() to "SELECT" about 3 million record in C+
+, and it takes several minutes to make it done with used memory
dramatically incresed(about 200MB).
it seems when i using PQexecParams(), i can't use the query result
before all the data is sent to client.
is there something like server side cursor in libpq?
or is there any other way to do this in c++?
some articles say that query for large amount of data is
automaticall handled well by pg, but i can't see how.

thanks~~~~

libpqxx is what you need. then you can use cursors in c++.

cheers,
henke