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Here we take into account the isolation property of a transaction. The strongest isolation is known to beSerializable, implying all transactions pretend to execute sequentially. This is very convenient for a user forusersr because it prevents hidden data corruption and security issues. The price for this may be reduced throughput/latency due to increased overhead from CC protocol. Additional An additional option is to allow a user to choose a weaker isolation level, likeSNAPSHOT. The ultimate goal is to implement Serializability without sacrificing performance too much, having Serializable as the default isolation level. 

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This is the natural way to use transactions. 

Score: 3

Read-only (long-lived) transactions

Such transactions can be used to build analytical reports, which can take minutes , without affecting (and being affected by) concurrent OLTP load. Any SQL select for read query is naturally mapped to this type of a transactionaransaction. These transactions can run for several minutes.  Such transactions can also read snapshot data in the past, at some timestamp. This is also known as HTAP.

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