<p dir="ltr">We'll need a bit more info before any viable advice can be given. How big is that polygon for the overlaps? Any error messages in the postgresql logs? Is there just one date's scenes in the table or is it longitudinal?</p>

<p dir="ltr">-bborie</p>
<div class="gmail_quote">On Mar 17, 2014 9:16 AM, "Jackie" <<a href="mailto:justaniceguy.nguyen@gmail.com">justaniceguy.nguyen@gmail.com</a>> wrote:<br type="attribution"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">

  

    
  
  <div bgcolor="#FFFFFF" text="#000000">
    <span style="text-indent:0px;letter-spacing:normal;font-variant:normal;text-align:start;font-style:normal;display:inline!important;font-weight:normal;float:none;line-height:normal;color:rgb(34,34,34);text-transform:none;font-size:13px;white-space:normal;font-family:Arial,Helvetica,sans-serif;word-spacing:0px">Hi PostGIS users,</span>
    <div style="text-indent:0px;letter-spacing:normal;font-variant:normal;text-align:start;font-style:normal;font-weight:normal;padding:0px;vertical-align:baseline;line-height:normal;color:rgb(34,34,34);text-transform:none;font-size:13px;white-space:normal;margin:0px;font-family:Arial,Helvetica,sans-serif;border:0px;word-spacing:0px">
I have a PostGIS database,
      which stores raster from Landsat 8. Each scene was divided with
      tile-size 500x500. Then each row in database will keep 1 tile with
      11 bands (except band No. 8).</div>
    <div style="text-indent:0px;letter-spacing:normal;font-variant:normal;text-align:start;font-style:normal;font-weight:normal;padding:0px;vertical-align:baseline;line-height:normal;color:rgb(34,34,34);text-transform:none;font-size:13px;white-space:normal;margin:0px;font-family:Arial,Helvetica,sans-serif;border:0px;word-spacing:0px">
I'm trying to ST_Union()
      about 1179 raster-tiles with 3 bands (2,3,4) and pgAdminIII shows
      a window said "Connection lost - Try to reconnect database";</div>
    <div style="text-indent:0px;letter-spacing:normal;font-variant:normal;text-align:start;font-style:normal;font-weight:normal;padding:0px;vertical-align:baseline;line-height:normal;color:rgb(34,34,34);text-transform:none;font-size:13px;white-space:normal;margin:0px;font-family:Arial,Helvetica,sans-serif;border:0px;word-spacing:0px">
Here's my query:</div>
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<font style="margin:0px;padding:0px;border:0px;vertical-align:baseline" face="courier new, monospace">SELECT ST_Union(rast,
        ARRAY[ROW(2,'LAST'),ROW(3,'<u></u>LAST'),ROW(4,'LAST')]::<u></u>unionarg[])</font></div>
    <div style="text-indent:0px;letter-spacing:normal;font-variant:normal;text-align:start;font-style:normal;font-weight:normal;padding:0px;vertical-align:baseline;line-height:normal;color:rgb(34,34,34);text-transform:none;font-size:13px;white-space:normal;margin:0px;font-family:Arial,Helvetica,sans-serif;border:0px;word-spacing:0px">
<font style="margin:0px;padding:0px;border:0px;vertical-align:baseline" face="courier new, monospace">FROM landsat8</font></div>
    <div style="text-indent:0px;letter-spacing:normal;font-variant:normal;text-align:start;font-style:normal;font-weight:normal;padding:0px;vertical-align:baseline;line-height:normal;color:rgb(34,34,34);text-transform:none;font-size:13px;white-space:normal;margin:0px;font-family:Arial,Helvetica,sans-serif;border:0px;word-spacing:0px">
<font style="margin:0px;padding:0px;border:0px;vertical-align:baseline" face="courier new, monospace">WHERE ST_Overlaps(polygon,
        rast_geom_4326)</font></div>
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<font style="margin:0px;padding:0px;border:0px;vertical-align:baseline" face="courier new, monospace"><br>
      </font></div>
    <div style="text-indent:0px;letter-spacing:normal;font-variant:normal;text-align:start;font-style:normal;font-weight:normal;padding:0px;vertical-align:baseline;line-height:normal;color:rgb(34,34,34);text-transform:none;font-size:13px;white-space:normal;margin:0px;font-family:Arial,Helvetica,sans-serif;border:0px;word-spacing:0px">
<font style="margin:0px;padding:0px;border:0px;vertical-align:baseline" face="arial, sans-serif">I'm using PostGIS 2.1, my raster is
        retrieved from <a href="http://earthexplorer.usgs.gov/" style="margin:0px;padding:0px;border:0px;vertical-align:baseline;text-decoration:none;color:rgb(102,17,204)" target="_blank">earthexplorer.usgs.gov</a></font></div>

  </div>

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