sqlite3_step执行时间为10us,为什么这么耗时

int DATABASE_SetParameterValue(char *path, dm_hash_t hash, char *instances, char *new_value, unsigned flags)
{
    sqlite3_stmt *stmt;
    int err;
    int result = USP_ERR_INTERNAL_ERROR;        // Assume an error
    char *value_to_bind;
    char obfuscated_value[MAX_DM_SHORT_VALUE_LEN];
    int len;

    // Exit if this function is not being called from the data model thread
    if (OS_UTILS_IsDataModelThread(__FUNCTION__, PRINT_WARNING)==false)
    {
        return USP_ERR_INTERNAL_ERROR;
    }

    // Decide whether to obfuscate the value
    len = strlen(new_value);
    if (flags & OBFUSCATED_VALUE)
    {
        ObfuscatedCopy((unsigned char *)obfuscated_value, (unsigned char *)new_value, len);
        value_to_bind = obfuscated_value;
    }
    else
    {
        value_to_bind = new_value;
    }

    // Exit if unable to set the value of the hash in the prepared statement
    stmt = prepared_stmts[kSqlStmt_Set];
    err = sqlite3_bind_int64(stmt, 1, (db_hash_t)hash);
    if (err != SQLITE_OK)
    {
        USP_ERR_SQL_PARAM(db_handle, "sqlite3_bind_int");
        goto exit;
    }

    // Exit if unable to set the value of the instances in the prepared statement
    err = sqlite3_bind_text(stmt, 2, instances, SQLITE_ZERO_TERMINATED, SQLITE_STATIC);
    if (err != SQLITE_OK)
    {
        USP_ERR_SQL_PARAM(db_handle, "sqlite3_bind_text");
        goto exit;
    }

    // Exit if unable to set the new value of the parameter in the prepared statement
    err = sqlite3_bind_text(stmt, 3, value_to_bind, len, SQLITE_STATIC);
    if (err != SQLITE_OK)
    {
        USP_ERR_SQL_PARAM(db_handle, "sqlite3_bind_text");
        goto exit;
    }

    //LogSQLStatement("SET", path, stmt);

    // Exit if unable to perform the set
    err = sqlite3_step(stmt);
    if (err != SQLITE_DONE)     // We are not expecting any rows
    {
        USP_ERR_SQL_PARAM(db_handle, "sqlite3_step");
        goto exit;
    }

    // If the code gets here, then the parameter has been successfully set in the database
    result = USP_ERR_OK;

exit:
    // Always reset the statement in preparation for next time, even if an error occurred
    err = sqlite3_reset(stmt);
    if ((err != SQLITE_OK) && (result == USP_ERR_OK))
    {
        USP_ERR_SQL_PARAM(db_handle, "sqlite3_reset");
    }

    return result;
}

1.已经使用了sqlite3_prepare_v2的方法还是慢

2.设置PRAGMA synchronous = OFF还是不好使