Will insert and delete in tokudb need " read-modify-write"?

[郭枫]

From this blog Fast Updates with TokuDB, default update in MySQL needs "read-modify-write"，fast update doesn't need "read-modify-write",so I have some questions:

1. Do insert and  delete need "read-modify-write"?If not need,why not need since insert or delete also return how many rows are changed?

2.Even with fast updates, when many update messages batch is big enough, then these update message will be passed to leaf node, then does a read  still need ,but just read in batch?

[Rik Prohaska]

sql insert with tokudb always does a read for all unique keys including the primary key unless unique_checks is OFF.  then a message is injected into all of the index fractal trees.

sql delete with tokudb does a read to find the rows prior to deleting them so that affected rows is computed.  

fast updates avoid the reads when the sql statement is executed.  in place of read modify write, a modify message is injected into the fractal tree.

[郭枫]

Since fast updates occur， will “ fast deletes”（not need read and delete）come out？

在 2015年8月27日星期四 UTC+8上午3:59:45，Rik Prohaska写道：