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Overview
| Comment: | Add a list of shadow tables to the fts5 documentation. |
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| Downloads: | Tarball | ZIP archive |
| Timelines: | family | ancestors | descendants | both | trunk |
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1225bcc93d2bd30726368ce4f1d3eb7e |
| User & Date: | dan 2018-02-19 10:46:37.912 |
Context
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2018-02-20
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| 02:53 | First cut at a separate document for the printf() string formatters. (check-in: 664ed2dce4 user: drh tags: trunk) | |
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2018-02-19
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| 10:46 | Add a list of shadow tables to the fts5 documentation. (check-in: 1225bcc93d user: dan tags: trunk) | |
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2018-02-16
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| 14:31 | Enhance althttpd.c so that with the -DLOG_HEADER option, it records the complete http request header in logfile-hdr if the "FullHeaderLog" string occurs anyplace in the request path. (check-in: b1ce1a2b56 user: drh tags: trunk) | |
Changes
Changes to pages/fts5.in.
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DELETE statement executed by the user. This means that any operation
on an FTS3/4 table may turn out to be surprisingly slow, as FTS3/4
may unpredictably choose to merge together two or more large b-trees
within it. FTS5 uses incremental merging by default, which limits
the amount of processing that may take place within any given
INSERT, UPDATE or DELETE operation.
</ul>
<h1 id=appendix_b nonumber tags="fts5 shadow tables">
Appendix B: Shadow tables created by FTS5
</h1>
<p>
When an FTS5 virtual table is created in a database, between 3 and 5 real
tables are created in the database. These are known as "shadow" tables, and are
used by the virtual table module to store persistent data. They should not
be accessed directly by the user. Many other virtual table modules, including
[FTS3] and [rtree], also create and use shadow tables.
<p>FTS5 creates the following shadow tables. In each case the actual table name
is based on the name of the FTS5 virtual table (in the following table, replace
<name> with the name of the virtual table to find the actual shadow
table name).
<table striped=1>
<tr><th>Table Name<th>Contents
<tr><td><name>_data<td> This table contains most of the full-text index data.
<tr><td><name>_idx<td> This table contains the remainder of the full-text
index data. It is almost always much smaller than the <name>_data table.
<tr><td><name>_config<td> Contains the values of persistent
configuration parameters.
<tr><td><name>_content<td> Contains the actual data inserted into the
FTS5 table. This shadow table is not present for
[FTS5 contentless tables | contentless] or
[FTS5 external content tables|external content] FTS5 tables.
<tr><td><name>_docsize<td> Contains the size of each column of each
row in the virtual table in tokens. This shadow table is not present if
the [FTS5 columnsize option|"columnsize" option] is set to 0.
</table>
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