On Mon, Jun 08, 2009 at 05:53:42PM +0000, Martin Kersten wrote:
> Update of /cvsroot/monetdb/MonetDB5/src/optimizer
> In directory 23jxhf1.ch3.sourceforge.com:/tmp/cvs-serv7310
>
> Modified Files:
> Tag: May2009
> opt_joinpath.mx
> Log Message:
> Experimental stable code to deal with too large intermediate joins.
> It marks them as 'postpone' until at least one other join in the path
> has been executed. Multiple variations can be envisioned.
>
>
> U opt_joinpath.mx
> Index: opt_joinpath.mx
> ===================================================================
> RCS file: /cvsroot/monetdb/MonetDB5/src/optimizer/opt_joinpath.mx,v
> retrieving revision 1.47.2.1
> retrieving revision 1.47.2.2
> diff -u -d -r1.47.2.1 -r1.47.2.2
> --- opt_joinpath.mx 8 Jun 2009 10:56:25 -0000 1.47.2.1
> +++ opt_joinpath.mx 8 Jun 2009 17:53:40 -0000 1.47.2.2
> @@ -408,7 +408,9 @@
> {
> BAT *b;
> BUN estimate, e;
> - int i, j;
> + int i, j, k;
> + int *postpone= (int*) GDKzalloc(sizeof(int) *top);
> + int postponed=0;
>
> /* solve the join by pairing the smallest first */
> while (top > 2) {
> @@ -426,7 +428,7 @@
> stream_printf(cntxt->fdout,"#joinPath estimate join(%d,%d)
> %d\n", joins[i]->batCacheid,
> joins[i+1]->batCacheid,(int)e);
> #endif
> - if (e < estimate) {
> + if (e < estimate && ( !(postpone[i] && postpone[i+1])
> || postponed==top-1)) {
> estimate = e;
> j = i;
> }
> @@ -434,10 +436,28 @@
> @-
> BEWARE. you may not use a size estimation, because it
> may fire a BATproperty check in a few cases.
> +In case a join fails, we may try another order first before
> +abandoning the task.
> @c
> b = BATjoin(joins[j], joins[j + 1], BUN_NONE);
> - if (b==NULL)
> - return NULL; /* something seriously went wrong */
> + if (b==NULL){
> + if ( postpone[j]){
^^^^^^^^^^^
shouldn't this be (e.g.)
postpone[j] && postpone[j+1]
i.e., bailout (only) if the exact join has failed before,
not if an other join with the same (i.e., join(j-1,j))
has failed before?
... just a spontaneous idea ...
Stefan
> + GDKfree(postpone);
> + return NULL;
> + }
> + /* clear the GDKerrors */
> + if( cntxt->errbuf )
> + cntxt->errbuf[0]=0;
> + postpone[j] = TRUE;
> + postpone[j+1] = TRUE;
> + postponed++;
> + continue;
> + } else {
> + /* reset the postponed joins */
> + for( k=0; k<top; k++)
> + postpone[k]=FALSE;
> + postponed = 0;
> + }
> #ifdef DEBUG_OPT_JOINPATH
> stream_printf(cntxt->fdout, "#joinPath %d:= join(%d,%d)\n",
> b->batCacheid, joins[j]->batCacheid, joins[j +
> 1]->batCacheid);
> @@ -450,6 +470,7 @@
> for (i = j + 1; i < top; i++)
> joins[i] = joins[i + 1];
> }
> + GDKfree(postpone);
> #ifdef DEBUG_OPT_JOINPATH
> stream_printf(cntxt->fdout, "#joinPath final join %d and %d\n",
> joins[0]->batCacheid, joins[1]->batCacheid);
> #endif
>
>
> ------------------------------------------------------------------------------
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>
--
| Dr. Stefan Manegold | mailto:[email protected] |
| CWI, P.O.Box 94079 | http://www.cwi.nl/~manegold/ |
| 1090 GB Amsterdam | Tel.: +31 (20) 592-4212 |
| The Netherlands | Fax : +31 (20) 592-4312 |
------------------------------------------------------------------------------
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Check out the new simplified licensing option that enables unlimited
royalty-free distribution of the report engine for externally facing
server and web deployment.
http://p.sf.net/sfu/businessobjects
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