I have some libpq-using application code, in which fetching the data
follows this logic (after a statement has been prepared):
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PQexecPrepared(pg_result, pg_conn, pg_statement_name, input_param_cnt, param_values, param_lengths,
param_formats,result_format); PQntuples(&rows_in_result, pg_result); /* The application provides storage so that I
canpass a certain number of rows * (rows_to_pass_up) to the caller, and I repeat the following loop until * many
rows_to_pass_upcover all the rows_in_result (pg_row_num_base keeps the track * of where I am in the process. */ for
(introw_idx = 0; row_idx < rows_to_pass_up; ++row_idx) { const int pg_row_number = row_idx + pg_row_num_base;
for(int pg_column_number = 0; pg_column_number < result_column_cnt_ ++pg_column_number) { PQgetvalue(&value,
pg_result,pg_row_number, pg_column_number); PQgetlength(&length, pg_result, pg_row_number, pg_column_number); }
}
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My question is: am I doing the right thing from the "data size being
passed from BE to FE" perspective?
The code in `bin/psql' relies on the value of the FETCH_COUNT
parameter to build an appropriate
fetch forward FETCH_COUNT from _psql_cursor
command.
No equivalent of FETCH_COUNT is available at the libpq level, so I
assume that the interface I am using is smart enough not to send
gigabytes of data to FE.
Is that right? Is the logic I am using safe and good?
Where does the result set (GBs of data) reside after I call
PQexecPrepared? On BE, I hope?
Thanks,
-- Alex -- alex-goncharov@comcast.net --
