kdb paper section 4.2 The Single-threading is History Argument

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1

http://cs.nyu.edu/shasha/papers/hpts.pdf
High Volume Transaction Processing Without Concurrency Control, Two Phase Commit, SQL or C++

4.2 The Single-threading is History Argument

2.Once K has multithreading, intra-transaction parallelism can be used (e.g. to update the trade and position tables in a trading system in parallel). Intra-transaction parallelism also preserves the illusion of single-threaded transactions. The programmer would have to recognize the potential for such parallelism, but would be able to apply it easily since K has an operator that applies to each member of a list conceptually in parallel. In this case, the list would consist of operators on different tables and one would apply all these operators in parallel.

Q: Will this lead to a noupdate exception?

http://code.kx.com/wiki/Reference/peach

2

q -p 6000 -s 2 # fails

q -p 6000 -s 1 # fails

q -p 6000 # works

Microsoft Windows [Version 6.1.7601]

Copyright (c) 2009 Microsoft Corporation. All rights reserved.


C:\Users\yan>q -p 6000 -s 2

KDB+ 3.2 2015.02.10 Copyright (C) 1993-2015 Kx Systems

w32/ 4()core 4095MB yan yani5 192.168.1.2 NONEXPIRE


q)quote:(a:til 1);

q)trade:(a:til 1);

q){update a:a+1 from x} peach quotetrade

k){x’:y}

'noupdate: . quote

@

{update a:a+1 from x}':

quotetrade

q.q))

3

k even has its own theme song.



https://www.youtube.com/watch?list=PLF55FBEA8A3BF6F38&t=1&v=KnhZygnHS-U



4

http://cs.nyu.edu/shasha/papers/hpts.pdf
High Volume Transaction Processing Without Concurrency Control, Two Phase Commit, SQL or C++

4.2 The Single-threading is History Argument

This said, we admit that our lack of concurrency control makes K unsuitable for IRS (U.S.

tax authority) style databases. So be it

Q: What are “IRS (U.S. tax authority) style databases”?

5

Are my annotations in the diagram blow correct?