http://dba-oracle.com/m_direct_path_read.htm WebMar 12, 2013 · An Oracle session waits for a direct read I/O request to complete on the direct path read wait event. Direct I/O is normally used when reading from sort segments. Parallel query slaves also use direct I/O when scanning a table or index. As of Oracle 8.1.7, there is a separate direct read I/O wait event for LOB segments - direct path read (lob).
WebJul 26, 2024 · direct path read较高的可能原因有: 1. 大量的磁盘排序操作,order by, group by, union, di stinct, ... 一则 Oracle 等待 事件 “ di rect path read " 排查思路 Web为了排序工作在临时区域读写时,等待direct path read temp、direct path write temp事件。这个等待事件收从oracle 10g起被分类的,oracle 9i为止是通过direct path read、direct path write等待观察的。排序段上的 direct path I/O是在需要排序的数据比排序所分配的PGA内存区大时发生的。 bootstrap outline input
Oracle Database - direct path read temp and direct path read …
WebThe session is waiting for a direct read to complete. A direct read is a physical I/O from a data file that bypasses the buffer cache and reads the data block directly into process-private memory. If asynchronous I/O is supported (and in use), then Oracle can submit I/O requests and continue processing. Oracle can then pick up the results of ... WebJul 28, 2024 · WAIT #2177686296376: nam='direct path read temp' ela= 2457 file number=201 first dba=227552 block cnt=31 obj#=241772 tim=3536780269333 WAIT #2177686296376: nam='direct path read temp' ela= 577 file number=201 first dba=226944 block cnt=31 obj#=241772 tim=3536780301955 ... 原因: 解决方案: 参考: My Oracle … Webapp 通过系统调用 sys_read() 读取数据,从 new_sync_read 和 blkdev_direct_IO 可以看出,进程正在对磁盘进行直接读,也就是绕过了系统缓存,每个读请求都会从磁盘直接读,这其实就是导致 iowait 升高的原因,查看 app.c 中磁盘的打开方式,如下所示。 bootstrap ou tailwind