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[DMDB] Fix more errors
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@@ -33,7 +33,7 @@ The following rules were discussed in the lectures:
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\item Natural join operations are associative, so are theta joins (with restrictions)
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\[
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(E_1 \bowtie E_2) \bowtie E_3 = E_1 \bowtie (E_2 \bowtie E_3)
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\qquad (E_1 \bowtie_{\theta_1} E_2) \bowtie_{\theta_2 \land \theta_3} = E_1 \bowtie_{\theta_1 \land \theta_3} (E_2 \bowtie_{\theta_2} E_3)
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\qquad (E_1 \bowtie_{\theta_1} E_2) \bowtie_{\theta_2 \land \theta_3} E_3 = E_1 \bowtie_{\theta_1 \land \theta_3} (E_2 \bowtie_{\theta_2} E_3)
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\]
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This allows for joins to be performed in different orders, allowing us to do the most selective first (fewer rows)
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\item Pushdown selection:
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@@ -1,4 +1,4 @@
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Adaptive Radix Trees (ARTs) are mainly used to ensure primary key constraints and to speed up point and highly selective queries (selectivity <0.1\%).
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Adaptive Radix Trees (ARTs) are mainly used to ensure primary key constraints and to speed up point and highly selective queries (selectivity $<0.1\%$).
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It can also be manually created using \texttt{CREATE INDEX} and are automatically created for columns with a \texttt{UNIQUE} or \texttt{PRIMARY KEY} constraint.
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The above applies to DuckDB, which is often similar to Postgres.
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@@ -1,6 +1,6 @@
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\subsection{Query Processing}
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\subsubsection{Sorting}
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Given $B$ frames of memory and $N$ records, we ahve
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Given $B$ frames of memory and $N$ records, we have (typically I/Os in pages to be read)
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\begin{itemize}
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\item \bi{Merge Sort}: $2N \cdot P$, with $P = (1 + \ceil{\log_{B - 1}\ceil{N \div B}})$ the number of passes.
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After the first pass, $\ceil{N \div B}$ number of sorted runs were created (typically)
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@@ -9,6 +9,7 @@ The following things are typically important to know very well (not exhaustive)
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\item Conflict Serializability
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\item Core concepts of Vector Search
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\item Recoverability (both the normal techniques, plus Snapshot Isolation and 2-Phase Locking (and strict variant thereof))
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\item Rewriting rules
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\end{todolist}
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Note that since this course is taught (quite) poorly, there may be wrong questions or possibly even questions that are somewhat outside the scope of this course
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