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. Thank you.
On Jun 16, 2010, at 11:24 PM, backup wrote:
> hi, everyone,
> I program in an embaded system: ARM9 soc S3C2410 +Linux 2.4+sqlite
> 3.3.
> All data store in NAND FLASH , the file system is YAFFS .
> My question is the function "sqlite3_exec(.....)" take too many
> seconds,
> the following is my source code, please see the "printf" 's comment,
> every "sqlite3_exec(.....)" takes 5 seconds, but how to reduce
> the time?
>
> //------------------------------ start of code
> #define RECORD_NUM 1
>
> char QueryData(void)
> {
> struct timeval tpstart,tpend;
> float timeuse;
>
> char ErrorFlag=1;
> unsigned int di,dj,dk;
> DataBuffer[0]='\0'; //DataBuffer is goblal variable
> sprintf(sqlstr,"select * from db where isSent=0 limit
> %d;",RECORD_NUM);
> p(semid);
>
> gettimeofday(&tpstart,NULL);
> rc = sqlite3_exec(db, sqlstr, SQLCallBack, 0, &zErrMsg);
> gettimeofday(&tpend,NULL);
> timeuse=1000000*(tpend.tv_sec-tpstart.tv_sec)+
> tpend.tv_usec-tpstart.tv_usec;
> timeuse/=1000000;
> printf("sqlite3 select * Used Time：%f\n",timeuse); // print value :5
> seconds
>
>
> v(semid);
>
> sprintf(sqlstr,"update db set isSent=1 where ID in (select ID from
> db where isSent=0 limit %d);",RECORD_NUM);
> p(semid);
> gettimeofday(&tpstart,NULL);
>
>
> rc = sqlite3_exec(db, sqlstr, 0, 0, &zErrMsg);
>
> gettimeofday(&tpend,NULL);
> timeuse=1000000*(tpend.tv_sec-tpstart.tv_sec)+
> tpend.tv_usec-tpstart.tv_usec;
> timeuse/=1000000;
> printf("sqlite3 update Used Time：%f\n",timeuse); //print value : 5s
>
>
>
> v(semid);
> }
> static int SQLCallBack(void *NotUsed, int argc, char **argv, char
> **azColName)
> {
>
> struct timeval tpstart,tpend;
> float timeuse;
>
>
> int i;
> char tstr[500];
> gettimeofday(&tpstart,NULL);
>
> // argv[0] is ID ,no use for server
> sprintf(tstr,"'%s',",argv[1]);
> strcat(DataBuffer,tstr);
> for(i=2; i<argc; i++){
> // printf("%s,",argv[i] ? argv[i] : "N");
> sprintf(tstr,"%s,",argv[i]);
> strcat(DataBuffer,tstr);
> }
> strcat(DataBuffer,"\n");
>
> gettimeofday(&tpend,NULL);
> timeuse=1000000*(tpend.tv_sec-tpstart.tv_sec)+
> tpend.tv_usec-tpstart.tv_usec;
> timeuse/=1000000;
> printf("SQLCallBack Used Time：%f\n",timeuse); // print value :
> 0.000280s
>
> return 0;
> }
>
> //-------------------------- end of code
>
>
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D. Richard Hipp
d...@hwaci.com
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