Oracle 9i RAC Cache Fusion

最新推荐文章于 2021-04-06 19:45:20 发布

转载最新推荐文章于 2021-04-06 19:45:20 发布 · 61 阅读

本文介绍了DLMMaster机制中如何处理节点间同一数据块的使用冲突。当Node1正在使用某个数据块的同时，Node2请求同一数据块时，DLMMaster会协调DBWriter将数据块写入数据库文件，并确保两节点拥有最新版本的数据块。

when there is a block which is using on Node1 and at the same time, there is a request on Node2 for the same block.
DLM Master catch the status and let DBWR(DB Writer) write the block to Database file and this block is read by node2.

At last, if check point occurs on node1 , but the last version of block b is on node2 , and the old image of block b is on node1, then node1 notify the GCS and GCS send write-disk command to node2 . Node2 write block b on its local buffer to disk and then notify GCS . Finally , the GCS notify the other nodes to delete the past image (PI) .