how to implement selectivity injection in postgresql

<div dir="ltr"><pre class=""
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<pre class=""
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<code style="margin:0px;padding:0px;border:0px;vertical-align:baseline;font-family:Consolas,Menlo,Monaco,'Lucida
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New',monospace,serif;white-space:inherit;background-image:initial;background-repeat:initial"><spanclass=""
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style="margin:0px;padding:0px;border:0px;vertical-align:baseline;background:transparent">?</span></code></pre>
</pre><p style="margin:0px 0px
1em;padding:0px;border:0px;font-size:14px;vertical-align:baseline;clear:both;color:rgb(0,0,0);font-family:Arial,'Liberation
Sans','DejaVuSans',sans-serif;line-height:17.804800033569336px;background-image:initial;background-repeat:initial"> I
needto implement Selectivity injection as shown in above query in PostgreSQL by which we can inject selectivity of each
predicateor at least selectivity at relation level directly as part of query. Is there any on-going work on this front?
Ifthere is no ongoing work on this, How should I start implementing this feature?<p style="margin:0px 0px
1em;padding:0px;border:0px;font-size:14px;vertical-align:baseline;clear:both;color:rgb(0,0,0);font-family:Arial,'Liberation
Sans','DejaVuSans',sans-serif;line-height:17.804800033569336px;background-image:initial;background-repeat:initial"><br
/></div>