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Comment:Leave unspecified what it means for the sqlite_stat3 and sqlite_stat4 tables to have idx columns equal to their tbl column.
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SHA1:c538b41b9103463b25e1cc2b22a4d9de69be0830
User & Date: drh 2013-09-19 14:24:33
Context
2013-09-19
14:30
Clarification of the meaning of the stat column in sqlite_stat1. check-in: 83b2bf0c4d user: drh tags: trunk
14:24
Leave unspecified what it means for the sqlite_stat3 and sqlite_stat4 tables to have idx columns equal to their tbl column. check-in: c538b41b91 user: drh tags: trunk
14:14
Fix typos and enhance the text of documentation for 3.8.1 changes. check-in: 1d0df412df user: drh tags: trunk
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<blockquote><pre>
CREATE TABLE sqlite_stat3(tbl,idx,nEq,nLt,nDLt,sample);
</pre></blockquote>

<p>There are usually multiple entries in the sqlite_stat3 table for each index.
The sqlite_stat3.sample column holds the value of the left-most field of an
index identified by sqlite_stat3.idx and sqlite_stat3.tbl.
If the sqlite_stat3.idx and sqlite_stat3.tbl
columns hold the same value, then that row contains a sample from
the [INTEGER PRIMARY KEY] of the table.
The sqlite_stat3.nEq column holds the approximate
number of entries in the index whose left-most column exactly matches
the sample.  
The sqlite_stat3.nLt holds the approximate number of entries in the
index whose left-most column is less than the sample.
The sqlite_stat3.nDLt column holds the approximate
number of distinct left-most entries in the index that are less than
................................................................................
CREATE TABLE sqlite_stat4(tbl,idx,nEq,nLt,nDLt,sample);
</pre></blockquote>

<p>There are usually multiple entries in the sqlite_stat4 table for each index.
The sqlite_stat4.sample column holds the content of an index entry in
the [record format].  The index entry stored is taken from the
index identified by sqlite_stat4.idx and sqlite_stat4.tbl.
If sqlite_stat4.idx and sqlite_stat4.tbl
hold the same value, then that row contains a sample from
the [INTEGER PRIMARY KEY] of the table.
The sqlite_stat4.nEq column holds a list of integers where the K-th integer
is the approximate number of entries in the index whose left-most K columns
exactly match the K left-most columns of the sample.
The sqlite_stat4.nLt holds a list of integers where the K-th integer is
the approximate number of entries in the
index whose K left-most columns are collectively less than the 
K left-most columns of the sample.







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<blockquote><pre>
CREATE TABLE sqlite_stat3(tbl,idx,nEq,nLt,nDLt,sample);
</pre></blockquote>

<p>There are usually multiple entries in the sqlite_stat3 table for each index.
The sqlite_stat3.sample column holds the value of the left-most field of an
index identified by sqlite_stat3.idx and sqlite_stat3.tbl.



The sqlite_stat3.nEq column holds the approximate
number of entries in the index whose left-most column exactly matches
the sample.  
The sqlite_stat3.nLt holds the approximate number of entries in the
index whose left-most column is less than the sample.
The sqlite_stat3.nDLt column holds the approximate
number of distinct left-most entries in the index that are less than
................................................................................
CREATE TABLE sqlite_stat4(tbl,idx,nEq,nLt,nDLt,sample);
</pre></blockquote>

<p>There are usually multiple entries in the sqlite_stat4 table for each index.
The sqlite_stat4.sample column holds the content of an index entry in
the [record format].  The index entry stored is taken from the
index identified by sqlite_stat4.idx and sqlite_stat4.tbl.



The sqlite_stat4.nEq column holds a list of integers where the K-th integer
is the approximate number of entries in the index whose left-most K columns
exactly match the K left-most columns of the sample.
The sqlite_stat4.nLt holds a list of integers where the K-th integer is
the approximate number of entries in the
index whose K left-most columns are collectively less than the 
K left-most columns of the sample.