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-Change update strategy. Previous strategy of aggregated update statements acheived the lowest required execution of statements, but required a prepare per execute. This strategy uses a single prepare, though does not reduce execute. One prepare+thousands of executes is cheapare than a few dozen prepares+executes

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Final tally:
    before this change, a particular stress test:
        real    0m48.731s
        real    0m54.434s
    after this change, the same test:
        real    0m3.231s
        real    0m2.976s



git-svn-id: https://svn.code.sf.net/p/xcat/code/xcat-core/trunk@4675 8638fb3e-16cb-4fca-ae20-7b5d299a9bcd
This commit is contained in:
jbjohnso 2009-11-26 18:22:17 +00:00
parent c1a0633419
commit 577661b712
1 changed files with 14 additions and 12 deletions
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26
perl-xCAT/xCAT/Table.pm
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@ -1549,6 +1549,7 @@ sub setNodesAttribs {
#at the moment anyway
my @currnodes = splice(@$nodelist,0,$nodesatatime); #Do a few at a time to stay under max sql statement length and max variable count
my $insertsth; #if insert is needed, this will hold the single prepared insert statement
my $upsth;
while (scalar @currnodes) {
my %updatenodes=();
my %insertnodes=();
@ -1595,23 +1596,24 @@ sub setNodesAttribs {
}
$insertsth->execute(@args);
}
if (not $upsth and keys %updatenodes) { #prepare an insert statement since one will be needed
my $upstring = "UPDATE ".$self->{tabname}." set ";
foreach my $col (@orderedcols) { #try aggregating requests. Could also see about single prepare, multiple executes instead
$upstring .= "$col = ?, ";
}
$upstring =~ s/, / where $nodekey = ?/;
$upsth = $self->{dbh}->prepare($upstring);
}
if (scalar keys %updatenodes) {
my $upstring = "UPDATE ".$self->{tabname}." set ";
my @args=();
foreach my $col (@orderedcols) { #try aggregating requests. Could also see about single prepare, multiple executes instead
$upstring .= "$col = CASE $nodekey ";
foreach my $node (keys %updatenodes) {
$upstring .= "when '$node' then ? ";
foreach my $node (keys %updatenodes) {
my @args=();
foreach my $col (@orderedcols) { #try aggregating requests. Could also see about single prepare, multiple executes instead
push @args,$hashrec->{$node}->{$col};
}
$upstring .= "END, ";
push @args,$node;
$upsth->execute(@args);
}
$upstring =~ s/, $/ where $nodekey in (/;
$upstring .= "?,"x scalar(keys %updatenodes);
$upstring =~ s/,$/)/;
push @args,keys %updatenodes;
my $upsth = $self->{dbh}->prepare($upstring);
$upsth->execute(@args);
}
@currnodes = splice(@$nodelist,0,$nodesatatime);
}