Re: Index only scan sometimes switches to sequential scan for small amount of rows

From: Feike Steenbergen <feikesteenbergen(at)gmail(dot)com>
To: Jeff Janes <jeff(dot)janes(at)gmail(dot)com>
Cc: "pgsql-performance(at)postgresql(dot)org" <pgsql-performance(at)postgresql(dot)org>
Subject: Re: Index only scan sometimes switches to sequential scan for small amount of rows
Date: 2015-03-26 08:26:11
Message-ID: CAK_s-G1V85zP3b+Shu_=SkBcRBoYEhotqFSG_kxqZTWuqudikQ@mail.gmail.com
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Sorry, didn't respond to all your questions:

> What version of PostgreSQL are running? 'select version();'

PostgreSQL 9.3.4 on x86_64-pc-linux-gnu, compiled by gcc-4.6.real
(Ubuntu/Linaro 4.6.3-1ubuntu5) 4.6.3, 64-bit

> What do you get when to do "analyze verbose print_list"?

# analyze verbose print_list ;
INFO: analyzing "print_list"
INFO: "print_list": scanned 53712 of 53712 pages, containing 3626950
live rows and 170090 dead rows; 300000 rows in sample, 3626950
estimated total rows
ANALYZE
Time: 6656.037 ms

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