Skip to content
Snippets Groups Projects
Commit 0f4c073d authored by Peter J. Keleher's avatar Peter J. Keleher
Browse files

auto

parent 3308117c
No related branches found
No related tags found
No related merge requests found
......@@ -81,7 +81,7 @@ guarantees. Assume invariant *x == y*:
Both preserve consistency in isolation, but not w/ this schedule and dirty writes.
## Isolation guarantees:
## Isolation guarantee definitions:
"**read uncommitted**" (PL-1)
- writes to each obj totally ordered (prohibits dirty writes)
......@@ -92,10 +92,17 @@ Both preserve consistency in isolation, but not w/ this schedule and dirty write
- no dirty writes, reads
- implement w/ buffers (though doesn't guarantee recency)
"**repeatable read**" (cut (*snapshot*) isolation)
- item cut iso (multiple different values): buffer reads
- predicate cut iso (cut over "SELECT ..WHERE....")
- impl both w/ buffering
"**repeatable read**"
- **cut** (*snapshot*) **isolation**
- single piece of data
- this is the usual meaning of RR
- implement by buffering read values
- **item cut isolation**
- multiple different values
- implement by buffering reads
- **predicate cut isolation*
- cut over "SELECT ..WHERE....") (phantom anomalies)
- implement by caching entire logical ranges
----
### Unachievable isolation levels with partitions:
......
0% Loading or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment