On 2010-10-06 15:13, peter qin wrote:

Dear all, Yesterday,I had done a test about the speed of MonetDB.I used the example code make a test.the red part is my adding code.

I don't see any red, but I'm guessing you added the for loop inserting 10000 records. There are two main reasons this is slow: - There are 10000 interactions with the server. This takes time. Normally the best way to enter data into MonetDB/SQL is to use the COPY INTO command which can read from a CSV file. - The server uses autocommit by default. That means, every query is a separate transaction. You'll get a speed up if you first (before the CREATE TABLE) call update(dbh, "START TRANSACTION"); and after the for loop call update(dbh, "COMMIT"); In this way you tell the server that the whole table creation and filling is a single transaction, so you'll only get that overhead once.

#include #include #include

void die(Mapi dbh, MapiHdl hdl) { if (hdl != NULL) { mapi_explain_query(hdl, stderr); do { if (mapi_result_error(hdl) != NULL) mapi_explain_result(hdl, stderr); } while (mapi_next_result(hdl) == 1); mapi_close_handle(hdl); mapi_destroy(dbh); } else if (dbh != NULL) { mapi_explain(dbh, stderr); mapi_destroy(dbh); } else { fprintf(stderr, "command failed\n"); } exit(-1); }

MapiHdl query(Mapi dbh, char *q) { MapiHdl ret = NULL; if ((ret = mapi_query(dbh, q)) == NULL || mapi_error(dbh) != MOK) die(dbh, ret); return(ret); }

void update(Mapi dbh, char *q) { MapiHdl ret = query(dbh, q); if (mapi_close_handle(ret) != MOK) die(dbh, ret); }

int main(int argc, char *argv[]) { Mapi dbh; MapiHdl hdl = NULL; char *name; char *age;

dbh = mapi_connect("localhost", 50000, "monetdb", "monetdb", "sql", "demo"); if (mapi_error(dbh)) die(dbh, hdl);

update(dbh, "CREATE TABLE emp (name VARCHAR(20), age INT)");

for(int i = 0;i<10000;i++) { update(dbh, "INSERT INTO emp VALUES ('John', 23)"); } //why this cast more then serveral minutes .can you help me?

hdl = query(dbh, "SELECT * FROM emp");

while (mapi_fetch_row(hdl)) { name = mapi_fetch_field(hdl, 0); age = mapi_fetch_field(hdl, 1); printf("%s is %s\n", name, age); }

mapi_close_handle(hdl); mapi_destroy(dbh);

return(0); }

Peter Qin peterqin1980@gmail.com

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