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Assorted Rants Tagged ‘Database’, page 1:

Scaling Stateful Objects

Quote: “it is DB which is usually The Bottleneck™ – it means that we’re saving this enormous amount of load, exactly where it really matters.”
Another Quote: “as discussed above, the real-world task is always about scaling the whole system, including database; and in this regard Stateless-App-based systems exhibit significant problems.”

Databases and RAIDs

Quote: “for quite a few applications out there, the most important feature of the RAID is not even redundancy, but greatly improved write latency. Moreover – this is the thing which we cannot possibly get from software RAID (!).”
Another Quote: “As a rule of thumb – I am trying to keep the size of OLTP DB small enough to fit into RAM of the OLTP DB Server.”

Indirect and Client-Centric Payment Processing. Logging and Reconciliation

Quote: “Fortunately, there is a neat crypto-trick which makes this schema usable for Server-oriented games in general – and multi-player games in particular”
Another Quote: “if you’re using TCP to communicate, you should log everything right before it goes into your send() call (and right after it comes out of your recv() call”

Direct Payment Processing. Recovery from ‘Unknown’ Transaction Status. PCI DSS.

Quote: “With the Direct Processing, customer should trust us (the merchant) with their details”
Another Quote: “On the other hand, most of PCI DSS requirements make perfect sense regardless of formal compliance”

Payment Processing. Credit Cards. Chargebacks and Collateral Damage

Quote: “Chargeback monster will come from under the bed and will eat all your hard-earned money!”
Another Quote: “it is trivial to develop a system with guaranteed zero chargeback rate – to achieve this, it is sufficient to decline each and every transaction at pre-filter stage”

Gradual OLTP DB Development – from Zero to 10 Billion Transactions per Year and Beyond

Quote: “to make an efficient representation usable for OLAP – we need to modify our data on its way to OLAP replicas”
Another Quote: “Each of the DB Server Apps is a replica master, but all replica targets are within the same Replica DB”

Representing The Same Data Structure in SQL and NoSQL (from Classical Codd-style SQL to Key-Value NoSQL with SQL-with-XML and Structured NoSQL in between)

Quote: “while duplication MAY indeed improve performance – undue duplication also MAY hit performance pretty badly”
Another Quote: “NoSQL will usually call for another denormalisation on top of what we’ve described above for SQL-with-XML.”