netcdf-c/libdap2/cache.c
Dennis Heimbigner 9fe1223316
2011-04-17 18:56:10 +00:00

305 lines
9.1 KiB
C

/*********************************************************************
* Copyright 1993, UCAR/Unidata
* See netcdf/COPYRIGHT file for copying and redistribution conditions.
* $Header$
*********************************************************************/
#include "ncdap3.h"
#include "dapodom.h"
#include "dapdump.h"
/* Return 1 if we can reuse cached data to address
the current get_vara request; return 0 otherwise.
Target is in the constrained tree space.
Currently, if the target matches a cache that is not
a whole variable, then match is false.
*/
int
iscached(NCDAPCOMMON* nccomm, CDFnode* target, NCcachenode** cachenodep)
{
int i,j,found,index;
NCcache* cache;
NCcachenode* cachenode;
found = 0;
if(target == NULL) goto done;
/* Match the target variable against the prefetch, if any */
/* Note that prefetches are always whole variable */
cache = nccomm->cdf.cache;
cachenode = cache->prefetch;
if(cachenode!= NULL) {
for(found=0,i=0;i<nclistlength(cachenode->vars);i++) {
CDFnode* var = (CDFnode*)nclistget(cachenode->vars,i);
if(var == target) {
if(cachenodep) *cachenodep = cachenode;
found=1;
goto done;
}
}
}
/*search other cache nodes starting at latest first */
index = 0;
for(i=nclistlength(cache->nodes)-1;i>=0;i--) {
cachenode = (NCcachenode*)nclistget(cache->nodes,i);
/* We currently do not try to match constraints;
If the cachenode is constrained, then skip it
*/
if(!cachenode->wholevariable) continue;
for(found=0,j=0;j<nclistlength(cachenode->vars);j++) {
CDFnode* var = (CDFnode*)nclistget(cachenode->vars,j);
if(var == target) {found=1;index=i;break;}
}
if(found) break;
}
if(found) {
ASSERT((cachenode != NULL));
if(nclistlength(cache->nodes) > 1) {
/* Manage the cache nodes as LRU */
nclistremove(cache->nodes,index);
nclistpush(cache->nodes,(ncelem)cachenode);
}
if(cachenodep) *cachenodep = cachenode;
}
done:
#ifdef DEBUG
fprintf(stderr,"iscached: search: %s\n",makesimplepathstring3(target));
if(found)
fprintf(stderr,"iscached: found: %s\n",dumpcachenode(cachenode));
else
fprintf(stderr,"iscached: notfound\n");
#endif
return found;
}
/* Compute the set of prefetched data;
note that even if caching is off, we will
still prefetch the small variables.
*/
NCerror
prefetchdata3(NCDAPCOMMON* nccomm)
{
int i,j;
NCerror ncstat = NC_NOERR;
NClist* allvars = nccomm->cdf.varnodes;
DCEconstraint* constraint = nccomm->oc.dapconstraint;
NClist* vars = nclistnew();
NCcachenode* cache = NULL;
DCEconstraint* newconstraint = NULL;
/* Check if we can do constraints */
if(FLAGSET(nccomm->controls,NCF_UNCONSTRAINABLE)) { /*cannot constrain*/
/* If we cannot constrain, then pull in everything */
for(i=0;i<nclistlength(allvars);i++) {
nclistpush(vars,nclistget(allvars,i));
}
} else { /* can do constraints */
/* pull in those variables of sufficiently small size */
for(i=0;i<nclistlength(allvars);i++) {
CDFnode* var = (CDFnode*)nclistget(allvars,i);
size_t nelems = 1;
/* If var is a sequence or under a sequence, then never prefetch */
if(var->nctype == NC_Sequence || dapinsequence(var)) continue;
/* Compute the # of elements in the variable */
for(j=0;j<nclistlength(var->array.dimensions);j++) {
CDFnode* dim = (CDFnode*)nclistget(var->array.dimensions,j);
nelems *= dim->dim.declsize;
}
if(nelems <= nccomm->cdf.smallsizelimit)
nclistpush(vars,(ncelem)var);
}
}
/* If there are no vars, then do nothing */
if(nclistlength(vars) == 0) {
nccomm->cdf.cache->prefetch = NULL;
goto done;
}
newconstraint = (DCEconstraint*)dceclone((DCEnode*)constraint);
/* Construct the projections for this set of vars */
/* Initially, the constraints are same as the merged constraints */
restrictprojection34(vars,newconstraint->projections);
/* similar for selections */
/* Currently do nothing */
ncstat = buildcachenode34(nccomm,newconstraint,vars,&cache,1);
if(ncstat) goto done;
newconstraint = NULL; /* buildcachenode34 takes control of newconstraint */
cache->wholevariable = 1; /* All prefetches are whole variable */
if(FLAGSET(nccomm->controls,NCF_SHOWFETCH)) {
nclog(NCLOGNOTE,"prefetch.");
}
#ifdef DEBUG
/* Log the set of prefetch variables */
NCbytes* buf = ncbytesnew();
ncbytescat(buf,"prefetch.vars: ");
for(i=0;i<nclistlength(vars);i++) {
CDFnode* var = (CDFnode*)nclistget(vars,i);
ncbytescat(buf," ");
ncbytescat(buf,makesimplepathstring3(var));
}
ncbytescat(buf,"\n");
nclog(NCLOGNOTE,"%s",ncbytescontents(buf));
ncbytesfree(buf);
#endif
/* Make cache node be the prefetch node */
nccomm->cdf.cache->prefetch = cache;
done:
nclistfree(vars);
dcefree((DCEnode*)newconstraint);
if(ncstat) freenccachenode(nccomm,cache);
return THROW(ncstat);
}
NCerror
buildcachenode34(NCDAPCOMMON* nccomm,
DCEconstraint* constraint,
NClist* varlist,
NCcachenode** cachep,
int isprefetch)
{
NCerror ncstat = NC_NOERR;
OCerror ocstat = OC_NOERR;
OCconnection conn = nccomm->oc.conn;
OCobject ocroot = OCNULL;
CDFnode* dxdroot = NULL;
NCcachenode* cachenode = NULL;
char* ce = NULL;
if(FLAGSET(nccomm->controls,NCF_UNCONSTRAINABLE))
ce = NULL;
else
ce = buildconstraintstring3(constraint);
ocstat = dap_oc_fetch(nccomm,conn,ce,OCDATADDS,&ocroot);
nullfree(ce);
if(ocstat) {THROWCHK(ocerrtoncerr(ocstat)); goto done;}
ncstat = buildcdftree34(nccomm,ocroot,OCDATA,&dxdroot);
if(ncstat) {THROWCHK(ncstat); goto done;}
/* regrid */
if(!FLAGSET(nccomm->controls,NCF_UNCONSTRAINABLE)) {
ncstat = regrid3(dxdroot,nccomm->cdf.ddsroot,constraint->projections);
if(ncstat) {THROWCHK(ncstat); goto done;}
}
/* create the cache node */
cachenode = createnccachenode();
cachenode->prefetch = isprefetch;
cachenode->vars = nclistclone(varlist);
cachenode->datadds = dxdroot;
cachenode->constraint = constraint;
cachenode->wholevariable = iswholeconstraint(cachenode->constraint);
/* save the root content*/
cachenode->ocroot = ocroot;
cachenode->content = oc_data_new(conn);
ocstat = oc_data_root(conn,ocroot,cachenode->content);
if(ocstat) {THROWCHK(ocerrtoncerr(ocstat)); goto done;}
/* capture the packet size */
ocstat = oc_raw_xdrsize(conn,ocroot,&cachenode->xdrsize);
if(ocstat) {THROWCHK(ocerrtoncerr(ocstat)); goto done;}
#ifdef DEBUG
fprintf(stderr,"buildcachenode: new cache node: %s\n",
dumpcachenode(cachenode));
#endif
/* Insert into the cache. If not caching, then
remove any previous cache node
*/
if(!isprefetch) {
NCcache* cache = nccomm->cdf.cache;
if(cache->nodes == NULL) cache->nodes = nclistnew();
/* remove cache nodes to get below the max cache size */
while(cache->cachesize + cachenode->xdrsize > cache->cachelimit) {
NCcachenode* node = (NCcachenode*)nclistremove(cache->nodes,0);
#ifdef DEBUG
fprintf(stderr,"buildcachenode: purge cache node: %s\n",
dumpcachenode(cachenode));
#endif
cache->cachesize -= node->xdrsize;
freenccachenode(nccomm,node);
}
/* Remove cache nodes to get below the max cache count */
/* If not caching, then cachecount should be 0 */
while(nclistlength(cache->nodes) > cache->cachecount) {
NCcachenode* node = (NCcachenode*)nclistremove(cache->nodes,0);
#ifdef DEBUG
fprintf(stderr,"buildcachenode: count purge cache node: %s\n",
dumpcachenode(node));
#endif
cache->cachesize -= node->xdrsize;
freenccachenode(nccomm,node);
}
nclistpush(nccomm->cdf.cache->nodes,(ncelem)cachenode);
cache->cachesize += cachenode->xdrsize;
}
#ifdef DEBUG
fprintf(stderr,"buildcachenode: %s\n",dumpcachenode(cachenode));
#endif
done:
if(cachep) *cachep = cachenode;
if(ocstat != OC_NOERR) ncstat = ocerrtoncerr(ocstat);
if(ncstat) {
freecdfroot34(dxdroot);
freenccachenode(nccomm,cachenode);
}
return THROW(ncstat);
}
NCcachenode*
createnccachenode(void)
{
NCcachenode* mem = (NCcachenode*)calloc(1,sizeof(NCcachenode));
return mem;
}
void
freenccachenode(NCDAPCOMMON* nccomm, NCcachenode* node)
{
if(node == NULL) return;
oc_data_free(nccomm->oc.conn,node->content);
oc_data_free(nccomm->oc.conn,node->content);
dcefree((DCEnode*)node->constraint);
freecdfroot34(node->datadds);
nclistfree(node->vars);
nullfree(node);
}
void
freenccache(NCDAPCOMMON* nccomm, NCcache* cache)
{
int i;
if(cache == NULL) return;
freenccachenode(nccomm,cache->prefetch);
for(i=0;i<nclistlength(cache->nodes);i++) {
freenccachenode(nccomm,(NCcachenode*)nclistget(cache->nodes,i));
}
nclistfree(cache->nodes);
nullfree(cache);
}
NCcache*
createnccache(void)
{
NCcache* c = (NCcache*)calloc(1,sizeof(NCcache));
c->cachelimit = DFALTCACHELIMIT;
c->cachesize = 0;
c->nodes = nclistnew();
c->cachecount = DFALTCACHECOUNT;
return c;
}