jmptrader

Prerequisites

• Oracle Instant Client SDK
• 64-bit tdm-gcc

Create a file called oci8.pc

ora=<instaclient-install-dir>
gcc=

jmptrader

#pragma once
#include <string>
#include <iostream>
#include <fstream>
#include <sstream>

class csvfile;

inline static csvfile& endrow(csvfile& file);
inline static csvfile& flush(csvfile& file);

jmptrader

When builing large strings with lots of concatenations in PL/SQL, custom approach like "use varchar2(32000) buffer to reduce the number of dbms_lob calls" makes sense even for Oracle 12.1.0.2.0.

The response time improvement is 4..300+ times :) depending on the DB version and API you use.

Note that simple v_clob || TO_CHAR (SYSTIMESTAMP) || ', ' ==> v_clob || TO_CLOB(TO_CHAR (SYSTIMESTAMP) || ', ') trick (note the extra to_clob) makes 24 times improvement for 11g. The trick is bad for 12c where results in 1.5x degradation.

The code was published 4 year ago as an answer to "How to Quickly Append VARCHAR2 to CLOB": http://www.talkapex.com/2009/06/how-to-quickly-append-varchar2-to-clob.html?showComment=1343235921606#c9077980873875311325