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Overview
| Comment: | Fix typo in the query planner documentation. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | branch-3.31 |
| Files: | files | file ages | folders |
| SHA3-256: |
c3875b77fa111717f4be82e5eb839943 |
| User & Date: | drh 2020-05-21 19:16:59 |
Context
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2020-05-21
| ||
| 19:16 | Fix typo in the query planner documentation. Leaf check-in: c3875b77fa user: drh tags: branch-3.31 | |
| 19:16 | Fix typo in the query planner documentation. check-in: f246e9b589 user: drh tags: trunk | |
|
2020-05-20
| ||
| 01:27 | Fix the INSERT syntax diagram so that it is not possible to go from DEFAULT VALUES to the upsert-clause. check-in: 8b88f8f240 user: drh tags: branch-3.31 | |
Changes
Changes to pages/queryplanner.in.
144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 |
<tcl>code {
SELECT price FROM fruitsforsale WHERE rowid=4;
}</tcl>
<p>
Since the information is stored in the table in rowid order, SQLite
can find the correct row using a binary search.
If the table contains N element, the time required to look up the
desired row is proportional to logN rather than being proportional
to N as in a full table scan. If the table contains 10 million elements,
that means the query will be on the order of N/logN or about 1 million
times faster.
</p>
<tcl>figure 3 #fig3 rowidlu.gif {Lookup By Rowid}</tcl>
|
| |
144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 |
<tcl>code {
SELECT price FROM fruitsforsale WHERE rowid=4;
}</tcl>
<p>
Since the information is stored in the table in rowid order, SQLite
can find the correct row using a binary search.
If the table contains N elements, the time required to look up the
desired row is proportional to logN rather than being proportional
to N as in a full table scan. If the table contains 10 million elements,
that means the query will be on the order of N/logN or about 1 million
times faster.
</p>
<tcl>figure 3 #fig3 rowidlu.gif {Lookup By Rowid}</tcl>
|