Re: Fast insertion indexes: why no developments
От | Greg Stark |
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Тема | Re: Fast insertion indexes: why no developments |
Дата | |
Msg-id | CAM-w4HMEd56iDYfJKNXeROxukK=VhQkpRwfnNoQdk3m_G5svMg@mail.gmail.com обсуждение исходный текст |
Ответ на | Re: Fast insertion indexes: why no developments (Claudio Freire <klaussfreire@gmail.com>) |
Ответы |
Re: Fast insertion indexes: why no developments
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Список | pgsql-hackers |
<div dir="ltr"><div class="gmail_extra"><br /><div class="gmail_quote">On Tue, Nov 5, 2013 at 5:30 PM, Claudio Freire <spandir="ltr"><<a href="mailto:klaussfreire@gmail.com" target="_blank">klaussfreire@gmail.com</a>></span> wrote:<br/><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="im">> Maybe there's value in minmax indexes for sequential data, but not for<br /> > random data, which is thetopic of this thread.<br /><br /><br /></div>Well, of course, they're not magic pixie dust.<br /><br /> But is your datareally random? (or normal?)</blockquote></div><br /></div><div class="gmail_extra">I think minmax indexes are more akinto bitmap indexes. They will be very effective for columns with low-cardinality, especially for columns that are veryclustered. In the extreme if all the values in some regions of the table are the same then minmax indexes would be optimal.I wouldn't expect them to be very effective for a highly selective column that isn't well clustered.<br /><br /></div><divclass="gmail_extra">It really sounds like you're describing a particular workload that btrees could just be moreoptimized for. Buffering all inserts in memory and merging them into the btree lazily is actually something Heikki hasproposed in the past. I'm not clear if that gets you all the benefits of the indexes you described or not but it seemsto target the particular problem you're having.<br clear="all" /></div><div class="gmail_extra"><br />-- <br />greg<br/></div></div>
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