Changeset: fb604b8c012d for MonetDB
URL: https://dev.monetdb.org/hg/MonetDB?cmd=changeset;node=fb604b8c012d
Modified Files:
sql/backends/monet5/sql_optimizer.c
Branch: Jul2017
Log Message:
Keep history of failed experiment
diffs (41 lines):
diff --git a/sql/backends/monet5/sql_optimizer.c
b/sql/backends/monet5/sql_optimizer.c
--- a/sql/backends/monet5/sql_optimizer.c
+++ b/sql/backends/monet5/sql_optimizer.c
@@ -60,11 +60,24 @@ SQLgetColumnSize(sql_trans *tr, sql_colu
return size;
}
+/*
+ * The maximal space occupied by a query is calculated
+ * under the assumption that the complete database should fit in memory.
+ * The assumption is that the plan does not contain duplicate bind operations.
+ * Calculation of the precise footprint is much more complex
+ * and can not deal with intermediate structures, or fast
+ * access using sorted probing.
+ *
+ * A run where we only take the size of a table only once,
+ * caused major degration on SF100 Q3 with SSD(>6x)
+ */
+
static lng
SQLgetSpace(mvc *m, MalBlkPtr mb, int prepare)
{
sql_trans *tr = m->session->tr;
lng size,space = 0, i;
+ str lasttable = 0;
for (i = 0; i < mb->stop; i++) {
InstrPtr p = mb->stmt[i];
@@ -90,9 +103,10 @@ SQLgetSpace(mvc *m, MalBlkPtr mb, int pr
continue;
/* we have to sum the cost of all three components of a
BAT */
- if (c && (!isRemote(c->t) && !isMergeTable(c->t))) {
+ if (c && (!isRemote(c->t) && !isMergeTable(c->t)) &&
(lasttable == 0 || strcmp(lasttable,tname)==0)) {
size = SQLgetColumnSize(tr, c, access);
- space += size; // accumulate once
+ space += size; // accumulate once per table
+ //lasttable = tname; invalidate this attempt
if( !prepare && size == 0 && ! t->system){
//mnstr_printf(GDKout,"found empty
column %s.%s.%s prepare %d size "LLFMT"\n",sname,tname,cname,prepare,size);
setFunctionId(p, emptybindRef);
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