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Remove _clear_cache, we are instead just going to let things age out and rely upon use_cache to control when a caller

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urgently needs to assure fresh data

git-svn-id: https://svn.code.sf.net/p/xcat/code/xcat-core/trunk@12648 8638fb3e-16cb-4fca-ae20-7b5d299a9bcd
This commit is contained in:
jbjohnso 2012-05-12 11:54:49 +00:00
parent 9ffff27d86
commit 83be6fd96e
1 changed files with 8 additions and 36 deletions
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44
perl-xCAT/xCAT/Table.pm
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@ -12,7 +12,9 @@
# -cache to persist so long as '_build_cache' calls concurrently stack (for NodeRange interpretation mainly) (done)
# -Allow plugins to define a staleness threshold for getNodesAttribs freshness (complicated enough to postpone...)
# so that actions requested by disparate managed nodes may aggregate in SQL calls
# reference count managed cache lifetime, if clear_cache is called, and build_chache has been called twice, decrement the counter
# cache lifetime is no longer determined strictly by function duration
# now it can live up to 5 seconds. However, most calls will ignore the cache unless using a special option.
# Hmm, potential issue, getNodesAttribs might return up to 5 second old data even if caller expects brand new data
# if called again, decrement again and clear cache
# for getNodesAttribs, we can put a parameter to request allowable staleneess
# if the cachestamp is too old, build_cache is called
@ -352,8 +354,6 @@ sub handle_dbc_request {
return $opentables{$tablename}->{$autocommit}->_set_use_cache(@args);
} elsif ($functionname eq '_build_cache') {
return $opentables{$tablename}->{$autocommit}->_build_cache(@args);
} elsif ($functionname eq '_clear_cache') {
return $opentables{$tablename}->{$autocommit}->_clear_cache(@args);
} else {
die "undefined function $functionname";
}
@ -2084,10 +2084,8 @@ sub getNodesAttribs {
my @nodeentries=$self->getNodeAttribs($_,\@attribs,%options);
$rethash->{$_} = \@nodeentries; #$self->getNodeAttribs($_,\@attribs);
}
$self->_clear_cache;
$self->{_use_cache} = 0;
if ($self->{tabname} ne 'nodelist') { #avoid calling clear_cache on nodelist twice
$self->{nodelist}->_clear_cache;
if ($self->{tabname} ne 'nodelist') {
$self->{nodelist}->{_use_cache} = 0;
}
return $rethash;
@ -2111,27 +2109,6 @@ sub _refresh_cache { #if cache exists, force a rebuild, leaving reference counts
return;
}
sub _clear_cache { #PRIVATE FUNCTION TO EXPIRE CACHED DATA EXPLICITLY
#This is no longer sufficient to do at destructor time, as Table objects actually live an indeterminite amount of time now
#TODO: only clear cache if ref count mentioned in build_cache is 1, otherwise decrement ref count
my $self = shift;
if ($dbworkerpid) {
return dbc_call($self,'_clear_cache',@_);
}
if ($self->{_cache_ref} > 1) { #don't clear the cache if there are still live references
$self->{_cache_ref} -= 1;
return;
} elsif ($self->{_cache_ref} == 1) { #If it is 1, decrement to zero and carry on
return;
#$self->{_cache_ref} = 0;
}
#it shouldn't have been zero, but whether it was 0 or 1, ensure that the cache is gone
$self->{_use_cache}=0; # Signal slow operation to any in-flight operations that may fail with empty cache
$self->{_cached_attriblist} = undef;
undef $self->{_tablecache};
undef $self->{_nodecache};
}
sub _build_cache { #PRIVATE FUNCTION, PLEASE DON'T CALL DIRECTLY
#TODO: increment a reference counter type thing to preserve current cache
#Also, if ref count is 1 or greater, and the current cache is less than 3 seconds old, reuse the cache?
@ -2147,10 +2124,6 @@ sub _build_cache { #PRIVATE FUNCTION, PLEASE DON'T CALL DIRECTLY
}
if (not $refresh and $self->{_cache_ref}) { #we have active cache reference, increment counter and return
#TODO: ensure that the cache isn't somehow still ludirously old
unless ($copts{noincrementref}) {
$self->{_cache_ref} += 1;
}
my $currattr;
my $cachesufficient=1;
foreach $currattr (@$attriblist) { #if any of the requested attributes are not cached, we must rebuild
@ -2159,6 +2132,10 @@ sub _build_cache { #PRIVATE FUNCTION, PLEASE DON'T CALL DIRECTLY
last;
}
}
if ($self->{_cachestamp} < (time()-5)) { #NEVER use a cache older than 5 seconds
$cachesufficient=0;
}
if ($cachesufficient) { return; }
#cache is insufficient, now we must do the converse of above
#must add any currently cached columns to new list if not requested
@ -2960,8 +2937,6 @@ sub getAllNodeAttribs
unless (%options{prefetchcache}) {
$self->{_use_cache} = 0;
$self->{nodelist}->{_use_cache}=0;
$self->_clear_cache();
$self->{nodelist}->_clear_cache();
}
$self->_build_cache($attribq);
$self->{nodelist}->_build_cache(['node','groups']);
@ -3015,11 +2990,8 @@ sub getAllNodeAttribs
}
}
}
$self->_clear_cache();
$self->{nodelist}->_clear_cache();
$self->{_use_cache} = 0;
$self->{nodelist}->{_use_cache} = 0;
xCAT::NodeRange::retain_cache(0);
$query->finish();
if ($hashretstyle) {
return $rethash;