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Note that index-only scans can affect idx_tup_fetch.

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An index-only scan that avoids heap fetches will increment idx_tup_read
but not idx_tup_fetch.
This commit is contained in:
Tom Lane 2011-10-08 11:09:18 -04:00
parent b324384f6b
commit c78d8cd146
1 changed files with 2 additions and 1 deletions
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doc/src/sgml/monitoring.sgml
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@ -507,7 +507,8 @@ postgres: <replaceable>user</> <replaceable>database</> <replaceable>host</> <re
considering bitmap scans, because <structfield>idx_tup_read</> counts
index entries retrieved from the index while <structfield>idx_tup_fetch</>
counts live rows fetched from the table; the latter will be less if any
dead or not-yet-committed rows are fetched using the index.
dead or not-yet-committed rows are fetched using the index, or if any
heap fetches are avoided by means of an index-only scan.
</para>
</note>