Andy Pavlo (www.cs.cmu.edu...) Slides: 15445.courses.... Notes 15445.courses.... 15-445/645 Intro to Database Systems (Fall 2022) Carnegie Mellon University 15445.courses....
Пікірлер: 7
@agkhall9 ай бұрын
This is one of the rawest intros to a recorded lecture I think I've ever seen.
@user-fq6kx2ye3o Жыл бұрын
Does the statement 'at 13:12, the strawman system is correct' hold true? Even if it only performs a single transaction, there is still a possibility of issues arising if the operations within the transaction access or modify the same record simultaneously. or am I missing something??
@andypavlo Жыл бұрын
Almost every DBMSs will execute queries within the same txn in sequential order. There are some optimizations you can do if you know there are no dependencies between queries in the txn (e.g., if they touch different tables, or if they need to run on different nodes). But you can only do this if the DBMS *knows* what queries the DBMS will execute ahead of time (e.g., in a UDF or stored procedure).
@Shwed198211 күн бұрын
assumption is that a transaction does not do two things simultaneously by itself.
@jamalhasanov2270 Жыл бұрын
How does the T1 proceeeded by the T2 at 43:46 yield A=960, B=1160? I guess it was possible if we had T2, then T1.
@mephistotel879 ай бұрын
It's an error on the slide. The left schedule and write one should produce the same result (the same effect), otherwise the are not eqiuvalent.