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SHA1 Hash:83b2bf0c4d3811e788aa22fa2fb2d0b289c72229
Date: 2013-09-19 14:30:37
User: drh
Comment:Clarification of the meaning of the stat column in sqlite_stat1.
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</pre></blockquote>

<p>There is normally one row per index, with the index identified by the
name in the sqlite_stat1.idx column.  The sqlite_stat1.tbl column is
the name of the table to which the index belongs.  In each such row, 
the sqlite_stat.stat column will be
a string consisting of a list of integers.  The first integer in this
list is the number of rows in the index and in the table.  The second
integer is the average number of rows in the index that have the same
value in the first column of the index.  The third integer is the average
number of rows in the index that have the same value for the first two
columns.  The N-th integer (for N>1) is the average number of rows in 

the index which have the same value for the first N-1 columns.  For
a K-column index, there will be K+1 integers in the stat column.  If
the index is unique, then the last integer will be 1.

<p>The list of integers in the stat column can optionally be followed
by the keyword "unordered".  The "unordered" keyword, if it is present,
must be separated from the last integer by a single space.  If the
"unordered" keyword is present, then the query planner assumes that
the index is unordered and will not use the index for a range query.


<p>If the sqlite_stat1.idx column is NULL, then the sqlite_stat1.stat
column contains a single integer which is the (estimated) number of
rows in the table identified by sqlite_stat1.tbl.

<tcl>hd_fragment stat2tab {sqlite_stat2}</tcl>
<h4>2.5.4 The sqlite_stat2 table</h4>

<p>The sqlite_stat2 is only created and is only used if SQLite is compiled
with SQLITE_ENABLE_STAT2 and if the SQLite version number is between







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</pre></blockquote>

<p>There is normally one row per index, with the index identified by the
name in the sqlite_stat1.idx column.  The sqlite_stat1.tbl column is
the name of the table to which the index belongs.  In each such row, 
the sqlite_stat.stat column will be
a string consisting of a list of integers.  The first integer in this
list is the approximate number of rows in the index and in the table.  
The second integer is the approximate average number of rows in the index
that have the same value in the first column of the index.  The third 
integer is the approximate average number of rows in the index that have 
the same value for the first two columns.  The N-th integer (for N>1) 
is the approximate average number of rows in 
the index which have the same value for the first N-1 columns.  For
a K-column index, there will be K+1 integers in the stat column.  If
the index is unique, then the last integer will be 1.

<p>The list of integers in the stat column can optionally be followed
by the keyword "unordered".  The "unordered" keyword, if it is present,
must be separated from the last integer by a single space.  If the
"unordered" keyword is present, then the query planner assumes that
the index is unordered and will not use the index for a range query
or for sorting.

<p>If the sqlite_stat1.idx column is NULL, then the sqlite_stat1.stat
column contains a single integer which is the approximate number of
rows in the table identified by sqlite_stat1.tbl.

<tcl>hd_fragment stat2tab {sqlite_stat2}</tcl>
<h4>2.5.4 The sqlite_stat2 table</h4>

<p>The sqlite_stat2 is only created and is only used if SQLite is compiled
with SQLITE_ENABLE_STAT2 and if the SQLite version number is between