Assorted Rants Tagged ‘Database’, page 1:

Abstract: My talk at ACCU2018

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Quote: “if we can commit several transactions at the same time – RDBMS needs to fsync() our DB logs to physical disks only once”

Another Quote: “if going our preferred way of single-writing-DB connection – make sure NOT to use RDBMS-level Group Commit”

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Quote: “with our app-level cache, we’re guaranteed to get exactly the same results as if we’d be querying the underlying database.”

Another Quote: “why settle for invalidation when we can modify cache accordingly, saving on the extra DB request when we’re dealing with the same USER again?”

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Quote: “Have I already mentioned that you DO need to understand execution plans?”

Another Quote: “DO keep in mind that maintaining indexes has its own cost”

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Quote: “If I was a compiler-with-ability-to-create-indexes-as-I-need-it – what would I do to make The Ideal Execution PlanTM for this request?”

Another Quote: “When we have that ideal-execution-plan – we still need to convince our SQL compiler to use it”

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Quote: “A correlated sub-query is a type of query, where inner query depends upon the outcome of the outer query in order to perform its execution.”

Another Quote: “Correlated sub-queries are slower.”

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Quote: “to realize how our queries are working – we need to start thinking in terms of so-called "execution plans".”

Another Quote: “it can be faster to use Table Scan rather than Index-Scan+fetch over such a low-selectivity index”

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