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@ -87,10 +87,9 @@ Simplified version (to get the idea)
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for each tuple tr in r: (for each tuple ts in s: test pair (tr, ts))
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```
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// TODO: Add seek information
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Block transfer cost: $n_r dot b_s + b_r$ block transfers would be required,
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where $b_r$ -- blocks in relation $r$, same for $s$. Each scan of the inner
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relation requires one seek, and the scan of the outer relation requires one seek
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per block, leading to a total of $2 dot b_r$ seeks.
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where $b_r$ -- blocks in relation $r$, same for $s$.
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== Block-nested join
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@ -276,8 +275,7 @@ The concept of conflict equivalence leads to the concept of conflict
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serializability. We say that a schedule $S$ is *conflict serializable* if it is
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conflict equivalent to a serial schedule.
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// TODO: rename to precedence
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=== Precedence graph
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=== Serializability graph
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Simple and efficient method for determining the conflict seriazability of a
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schedule. Consider a schedule $S$. We construct a directed graph, called a
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@ -312,15 +310,6 @@ locking protocol. We say that a locking protocol ensures conflict
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serializability if and only if all legal schedules are *conflict serializable*;
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in other words, for all legal schedules the associated $->$ relation is acyclic.
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*Recoverable* schedule is one where, for each pair of transactions $T_i$ and
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$T_j$ such that $T_j$ reads a data item previously written by $T_i$, the commit
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operation of $T_i$ appears before the commit operation of $T_j$.
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*Cascadeless* schedule is one where, for each pair of transactions $T_i$ and
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$T_j$ such that $T_j$ reads a data item previously written by $T_i$, the commit
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operation of $T_i$ appears before the read operation of $T_j$. Every cascadeless
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schedule is also recoverable.
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=== Lock-based
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*Shared Lock* -- If a transaction $T_i$ has obtained a shared-mode lock (denoted
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@ -486,8 +475,7 @@ $B=5;T_"disk"=0.001;T_"seek"=0.1$
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=== Nested-Loop Join Method
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+ Nested-loop join:
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- For each pattern in $r_1$, search all patterns in $r_2$.
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+ Total Combinations: $75435 dot 11456$
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+ Total Combinations: $75435 dot 11456=$
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+ Time Calculation for Nested-Loop Join:
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- Reading and searching time for each combination: $0.001+0.1=0.101 "ms"$
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- Total time: $75435 dot 11456 dot 0.101 = 87282519.36 "ms"$ [Authors comment:
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seems fishy]
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- Total time: $75435 dot 11456 dot 0.101 = 87282519.36 "ms"$
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