27 lines
780 B
Markdown
27 lines
780 B
Markdown
# lec11
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_this section still needs more info_
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## Query processing
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Keep in mind we are still concerned with systems like sqlite3.
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First we have to parse an input to validate it.
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Then we should also validate any semantics about the input, ensure that the given _tables, objects etc_ are correct.
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Finally we should somehow calculate the input: usually by converting the given expression to the equivalent relational algebra expression.
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If we can optimize this expression we can then create more efficient queries.
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To do this we take into account 3 main factors:
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1. I/O time
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* if we have to write something to disk over and over again then we
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2. Computational Time
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3. Required memory/disk space
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### Cost funtion
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## Performance of Disk and RAM
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## DB Block
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## Disk Buffers
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