On Dec 24, 2007 11:57 AM, Martijn van Oosterhout <[EMAIL PROTECTED]> wrote:
> However, I still think we're getting ahead of ourselves. Attached is a
> patch which I beleive will cut the number of blank tiles created by
> clients by between 50 and 80%. I beleive that we can make the DB much
> smaller, because the size of the blank tile DB is *independant* of the
> size of the OSM database. If we get it right I think the database
> should stabilise at a size much smaller than what it is now...
And attached is another patch, this time for the server side, that
should cut the number of stored blanks by 50% again. I don't have PHP
installed so I havn't been able to syntax check this one so be
careful. If people could review these patches I'd be very grateful.
Have a nice day,
--
Martijn van Oosterhout <[EMAIL PROTECTED]> http://svana.org/kleptog/
Index: Upload/Run/index.php
===================================================================
--- Upload/Run/index.php (revision 3473)
+++ Upload/Run/index.php (working copy)
@@ -189,7 +189,7 @@
else
SaveMetadata($TileList, $UserID, $VersionID);
- SaveBlankTiles($BlankTileList, $UserID);
+ SaveBlankTiles($BlankTileList, $UserID,$ValidTileset,$TilesetX, $TilesetY, $TilesetLayer);
return($Count);
}
@@ -220,7 +220,46 @@
#------------------------------------------------------------------------------------
# Save uploaded blank tiles in the database
#------------------------------------------------------------------------------------
-function SaveBlankTiles($BlankTileList, $UserID){
+function SaveBlankTiles($BlankTileList, $UserID, $ValidTileset, $TilesetX, $TilesetY, $TilesetLayer){
+ # First we run through the set to find the predominant type
+ $CommonType = 0;
+ $ReplaceList = array();
+
+ # This optimisation is only possible if we have a valid full tileset
+ if( $ValidTileset )
+ {
+ $CountTypes = array( -1 => 0, 1 => 0, 2 => 0 );
+
+ foreach($BlankTileList as $SqlSnippet){
+
+ list($X, $Y, $Z, $Layer, $Type) = explode(",", $SqlSnippet);
+ # If we find levels <12, we set a flag to enable old behaviour
+ if( $Z < 12 ) {
+ $CommonType = -2;
+ break;
+ }
+ # Since we save storage by storing in level 12, if we are given the type we have to use it
+ if( $Z == 12 ) {
+ $CommonType = $Type;
+ break;
+ }
+ $CountType[$Type]++;
+ }
+ # Determine the common type, if we have a choice
+ if( $CommonType == 0 )
+ {
+ if( $CountType[1] > $CountType[2] ) {
+ $CommonType = 1;
+ } else {
+ $CommonType = 2;
+ }
+ }
+ # Store the "common tile" at zoom-12, now we don't have to store this type at any lower levels...
+ if( $CommonType > 0 ) {
+ array_push( $ReplaceList, sprintf("(%d, %d, %d, '%s', %d, now(), %d)", $TilesetX, $TilesetY, 12, $TilesetLayer, $CommonType, $UserID) );
+ }
+ }
+
# Each element in BlankTileList is a snippet of values (x,y,z,type,size) for each tile
foreach($BlankTileList as $SqlSnippet){
@@ -230,25 +269,29 @@
moveRequest($X, $Y, REQUEST_ACTIVE, REQUEST_DONE, 0);
}
- # Make a blank tile
- if( $Type >= 0 )
+ # Make a blank tile. Level 12 and 15 are always stored, otherwise we only store tiles not equal to the "common tile"
+ if( $Type >= 0 && ($Z == 12 || $Z == 15 || $Type != $CommonType) )
{
- $Fields = "x, y, z, layer, type, date, user";
- $Values = sprintf("%s, now(), %d", $SqlSnippet, $UserID);
-
- $SQL = sprintf("replace into `tiles_blank` (%s) values (%s);", $Fields, $Values);
+ # Store the stuff to replace in the array
+ $Values = sprintf("(%s, now(), %d)", $SqlSnippet, $UserID);
+ array_push( $ReplaceList, $Values );
}
else
{
# Delete a blank tile
$SQL = sprintf("delete from `tiles_blank` where `x`=%d AND `y`=%s AND `z`=%s AND `layer`=%d", $X, $Y, $Z, $Layer);
+ mysql_query($SQL);
}
DeleteRealTile($X,$Y,$Z,$Layer);
-
- mysql_query($SQL);
logSqlError();
}
+ # Execute all queued replacements...
+ if( count($ReplaceList) > 0 ) {
+ $Fields = "x, y, z, layer, type, date, user";
+ $SQL = sprintf( "replace into `tiles_blank` (%s) values %s", $Fields, implode(",",$ReplaceList) );
+ mysql_query($SQL);
+ }
}
#------------------------------------------------------------------------------------
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