SQLite建立索引后插入变慢有关问题

////////////////////////////////////////////////////////////////////////////////// CppSQLite3 - A C++ wrapper around the SQLite3 embedded database library.//// Copyright (c) 2004 Rob Groves. All Rights Reserved. rob.groves@btinternet.com// // Permission to use, copy, modify, and distribute this software and its// documentation for any purpose, without fee, and without a written// agreement, is hereby granted, provided that the above copyright notice, // this paragraph and the following two paragraphs appear in all copies, // modifications, and distributions.//// IN NO EVENT SHALL THE AUTHOR BE LIABLE TO ANY PARTY FOR DIRECT,// INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING LOST// PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION,// EVEN IF THE AUTHOR HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.//// THE AUTHOR SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A// PARTICULAR PURPOSE. THE SOFTWARE AND ACCOMPANYING DOCUMENTATION, IF// ANY, PROVIDED HEREUNDER IS PROVIDED "AS IS". THE AUTHOR HAS NO OBLIGATION// TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.//// V3.0        03/08/2004    -Initial Version for sqlite3//// V3.1        16/09/2004    -Implemented getXXXXField using sqlite3 functions//                        -Added CppSQLiteDB3::tableExists()////////////////////////////////////////////////////////////////////////////////#include "CppSQLite3.h"#include <time.h>#include <iostream>using namespace std;int main(int argc, char** argv){        try    {        CppSQLite3DB db;        db.open("E:\\test.db");        int nRowsToCreate(20000000);        int i=0;        db.execDML("create table CALLHISTORY(CalledNumber varchar(20)  ,CallingNumber varchar(20) ,TimeStamp datetime)");        [color=#FF0000]db.execDML("create index hisindex on CALLHISTORY(CalledNumber)"); //此处加上索引后插入速度变慢，刚开始几十万的时候还可以，后来1万条要几十秒。但是没有索引就一直都很快[/color]        cout << " rows please wait..." << endl;        int times = 0;        srand(time(NULL));        while(times <1) //这里本来想测试多次的        {            CppSQLite3Statement stmt = db.compileStatement("insert into CALLHISTORY values (?, ?,?);");            db.execDML("begin transaction;");                for (i = 1; i <= nRowsToCreate; i++)            {                if( 0 == i %10000)                {                    cout <<  " Already insert" << i << " lines" << endl;                    db.execDML("commit transaction;");                    db.execDML("begin transaction;");                }                int j =rand()%500000;                time_t nowTime = time(NULL);                struct tm* pTm=NULL;                pTm = localtime(&nowTime);                char bufTime[32];                memset(bufTime,'\0',sizeof(bufTime));                sprintf(bufTime,"%04d-%02d-%02d %02d:%02d:%02d",pTm->tm_year+1900,pTm->tm_mon+1,                    pTm->tm_mday,pTm->tm_hour,pTm->tm_min,pTm->tm_isdst);                char buf[16];                sprintf(buf, "lys%06d", j);                stmt.bind(1, j);                stmt.bind(2, buf);                stmt.bind(3,bufTime);                stmt.execDML();                stmt.reset();            }            db.execDML("commit transaction;");        }    }    catch (CppSQLite3Exception& e)    {        cout << "error code =" << e.errorCode() << "msg = " << e.errorMessage()<< endl;    }    catch(...)    {        cout <<"Unknown error";    }    return 0;}