<div dir="ltr"><div class="gmail_default" style="font-family:monospace,monospace">Hey,</div><div class="gmail_default" style="font-family:monospace,monospace"></div><div class="gmail_default" style="font-family:monospace,monospace">first, about slow query question</div><div class="gmail_default" style><font face="monospace, monospace"><a href="https://wiki.postgresql.org/wiki/Slow_Query_Questions">https://wiki.postgresql.org/wiki/Slow_Query_Questions</a></font><br></div><div class="gmail_default" style><font face="monospace, monospace"><br></font></div><div class="gmail_default" style><font face="monospace, monospace">Now you need to identify the problem.<br>For this, you have mainly 2 tools : </font></div><div class="gmail_default" style><font face="monospace, monospace"> - EXPLAIN ANALYZE (how postgres understands your query, what indexes it uses, etc.)</font></div><div class="gmail_default" style><font face="monospace, monospace"> - postgres stats monitoring (individual function timing)</font></div><div class="gmail_default" style><font face="monospace, monospace"><br></font></div><div class="gmail_default" style><font face="monospace, monospace">Last, I suppose you are aware that with the view you defined, everytime you need to access it, you need to recompute it (cache may help you depending on the size of the result).<br>If it is not the expected behaviour, use MATERIAL VIEW or TABLE (possibly TEMP or</font> UNLOGGED <span style="font-family:monospace,monospace">).</span><br></div><div class="gmail_default" style><span style="font-family:monospace,monospace"><br></span></div><div class="gmail_default" style><span style="font-family:monospace,monospace"><br></span></div><div class="gmail_default" style><font face="monospace, monospace">Cheers,</font></div><div class="gmail_default" style><font face="monospace, monospace">Rémi-C</font></div><div class="gmail_extra"><br><div class="gmail_quote">2015-05-26 8:47 GMT+02:00 Ahmet Temiz <span dir="ltr"><<a href="mailto:ahmettemiz88@gmail.com" target="_blank">ahmettemiz88@gmail.com</a>></span>:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div style="font-size:small">hello</div><div style="font-size:small"><br></div><div style="font-size:small">My slope calculation is very slow.<br></div><div style="font-size:small">Can you advice me any better way to speed up slope calculation.</div><div style="font-size:small"><br></div><div style="font-size:small">here is the way I have used. </div><div style="font-size:small">-------</div><div><div>Hibernate: </div><div> CREATE VIEW vslp8 AS </div><div> WITH r AS ( select</div><div> ST_Transform(ST_Union(dem.rast), 32635) AS rast </div><div> FROM</div><div> rdem2 as dem </div><div> where</div><div> st_Intersects( st_transform(dem.rast, 32635) , ST_Transform( ST_GeomFromText('POLYGON((28.87774 40.44479446,28.87774 40.755545,29.4603534 40.755545,29.4603534 40.44479446,28.87774 40.44479446))',4326 ),32635))),</div><div><br></div><div>cx AS (SELECT</div><div> ST_AsRaster( sf.the_geom, r.rast) AS rast </div><div> FROM</div><div> ( SELECT</div><div> ST_Transform( ST_GeomFromText('POLYGON((28.87774 40.44479446,28.87774 40.755545,29.4603534 40.755545,29.4603534 40.44479446,28.87774 40.44479446))',</div><div> 4326 ),</div><div> 32635) AS the_geom ) sf CROSS </div><div> JOIN r ) </div><div> SELECT</div><div> ST_Clip(ST_Slope(r.rast, 1, cx.rast),</div><div> ST_Transform( ST_GeomFromText('POLYGON((28.87774 40.44479446,28.87774 40.755545,29.4603534 40.755545,29.4603534 40.44479446,28.87774 40.44479446))',</div><div> 4326 ), 32635)) AS rast </div><div> FROM</div><div> r CROSS </div><div> JOIN cx </div><div><br></div><div>-----</div><div><br></div><div>I will appreciate if you propose any way.</div><div><br></div><div>regards</div></div><div><br></div>-- <br><div><div dir="ltr"><div><div dir="ltr"><div>Ahmet Temiz<br>Jeoloji Müh.<br>Afet ve Acil Durum Yönetimi Başkanlığı<br>Bilgi İşlem Dairesi Başkanlığı-CBS Grubu<br><br><br>________________________<span class="HOEnZb"><font color="#888888"><br><br>Ahmet Temiz<br>Geological Eng.<br>Information Systems - GIS Group<br>Disaster and Emergency Management<br>of Presidency</font></span></div></div></div></div></div>
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