netcdf-c/libdap2/cache.c
Peter Hill c3bdf768ec
Merge branch 'main' into silence-libdap2-warnings
* main: (158 commits)
  Update release notes.
  Refactor macro _FillValue to NC_FillValue in support of https://github.com/Unidata/netcdf-c/issues/2858
  Remove appveyor config file.
  Add CI for a Windows Runner on Github Actions.
  Add cmake prefix path to appveyor config.
  Attempt to fix zlib-related error in appveyor.
  Correct typo.
  Remove check for libcurl unless it is necessary for required functionality.
  Rename the vendored strlcat symbol
  Fix conversion warnings in libdispatch
  Set flags to avoid warning messages if curl isn't found.
  Use modern cmake nomenclature for curl.
  Fix truncated-format warning in ncgen
  Fix some conversion warnings in ncgen3
  Fix some conversion warnings in ncgen3 generated files
  Regenerate ncgen3
  CMake: Add option to automatically regenerate ncgen3/ncgen
  Skip checking for duplicates if only one element in list
  Change format of backwards-loops
  Silence some conversion warnings in ncgen generated files
  ...
2024-04-25 09:54:21 +01:00

444 lines
13 KiB
C

/*********************************************************************
* Copyright 2018, UCAR/Unidata
* See netcdf/COPYRIGHT file for copying and redistribution conditions.
*********************************************************************/
#include "dapincludes.h"
#include "dapdump.h"
#include <stddef.h>
/*
Grads servers always require a constraint,
which does not necessarily happen during prefetch.
So this flag controls this. By default, it is on.
*/
#define GRADS_PREFETCH
static int iscacheableconstraint(DCEconstraint* con);
/* 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 found;
size_t j;
size_t 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) {
found = 0;
for(size_t 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(size_t i = nclistlength(cache->nodes); i-->0;) {
cachenode = (NCcachenode*)nclistget(cache->nodes,i);
/* We currently do not try to match constraints;
If the cachenode is constrained by more than
simple wholevariable projections, 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,(void*)cachenode);
}
if(cachenodep) *cachenodep = cachenode;
}
done:
#ifdef DEBUG
fprintf(stderr,"iscached: search: %s\n",makecdfpathstring(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.
Notes:
1. All prefetches are whole variable fetches.
2. If the data set is unconstrainable, we
will prefetch the whole thing
*/
NCerror
prefetchdata(NCDAPCOMMON* nccomm)
{
size_t i;
NCFLAGS flags;
NCerror ncstat = NC_NOERR;
NClist* allvars = nccomm->cdf.ddsroot->tree->varnodes;
DCEconstraint* urlconstraint = nccomm->oc.dapconstraint;
NClist* vars = nclistnew();
NCcachenode* cache = NULL;
DCEconstraint* newconstraint = NULL;
if(FLAGSET(nccomm->controls,NCF_UNCONSTRAINABLE)) {
/* If we cannot constrain and caching is enabled,
then pull in everything */
if(FLAGSET(nccomm->controls,NCF_CACHE)) {
for(i=0;i<nclistlength(allvars);i++) {
nclistpush(vars,nclistget(allvars,i));
}
} else { /* do no prefetching */
nccomm->cdf.cache->prefetch = NULL;
goto done;
}
} else {
/* pull in those variables previously marked as prefetchable */
for(i=0;i<nclistlength(allvars);i++) {
CDFnode* var = (CDFnode*)nclistget(allvars,i);
/* Most of the important testing was already done */
if(!var->basenode->prefetchable)
continue;
/* Do not attempt to prefetch any variables in the
nc_open url's projection list
*/
if(nclistcontains(nccomm->cdf.projectedvars,(void*)var))
continue;
/* Should be prefetchable */
nclistpush(vars,(void*)var);
if(SHOWFETCH) {
nclog(NCLOGDEBUG,"prefetch: %s",var->ncfullname);
}
}
}
/* If there are no vars, then do nothing */
if(nclistlength(vars) == 0) {
nccomm->cdf.cache->prefetch = NULL;
goto done;
}
/* Create a single constraint consisting of the projections for the variables;
each projection is whole variable. The selections are passed on as is.
Conditionally, The exception is if we are prefetching everything.
*/
newconstraint = (DCEconstraint*)dcecreate(CES_CONSTRAINT);
newconstraint->projections = nclistnew();
newconstraint->selections = dceclonelist(urlconstraint->selections);
for(i=0;i<nclistlength(vars);i++) {
DCEprojection* varprojection;
CDFnode* var = (CDFnode*)nclistget(vars,i);
/* Ignore invisible vars */
if(var->invisible) continue;
/* convert var to a projection */
ncstat = dapvar2projection(var,&varprojection);
if(ncstat != NC_NOERR) {THROWCHK(ncstat); goto done;}
nclistpush(newconstraint->projections,(void*)varprojection);
}
if(SHOWFETCH) {
char* s = dumpprojections(newconstraint->projections);
LOG1(NCLOGNOTE,"prefetch.final: %s",s);
nullfree(s);
}
flags = NCF_PREFETCH;
#ifndef GRADS_PREFETCH
if(nclistlength(allvars) == nclistlength(vars)) flags |= NCF_PREFETCH_ALL;
#endif
ncstat = buildcachenode(nccomm,newconstraint,vars,&cache,flags);
newconstraint = NULL; /* buildcachenodetakes control of newconstraint */
if(ncstat != OC_NOERR) goto done;
else if(cache == NULL) goto done;
else
cache->wholevariable = 1; /* All prefetches are whole variable */
/* Make cache node be the prefetch node */
nccomm->cdf.cache->prefetch = cache;
if(SHOWFETCH) {
LOG0(NCLOGNOTE,"prefetch.complete");
}
if(SHOWFETCH) {
char* s = NULL;
/* 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," ");
s = makecdfpathstring(var,".");
ncbytescat(buf,s);
nullfree(s);
}
ncbytescat(buf,"\n");
nclog(NCLOGNOTE,"%s",ncbytescontents(buf));
ncbytesfree(buf);
}
done:
nclistfree(vars);
dcefree((DCEnode*)newconstraint);
if(ncstat && cache != NULL) freenccachenode(nccomm,cache);
return THROW(ncstat);
}
NCerror
buildcachenode(NCDAPCOMMON* nccomm,
DCEconstraint* constraint,
NClist* varlist,
NCcachenode** cachep,
NCFLAGS flags)
{
NCerror ncstat = NC_NOERR;
OCerror ocstat = OC_NOERR;
OClink conn = nccomm->oc.conn;
OCddsnode ocroot = NULL;
CDFnode* dxdroot = NULL;
NCcachenode* cachenode = NULL;
char* ce = NULL;
int isprefetch = 0;
if((flags & NCF_PREFETCH) != 0)
isprefetch = 1;
#ifndef GRADS_PREFETCH
if((flags & NCF_PREFETCH_ALL) == 0)
#endif
ce = dcebuildconstraintstring(constraint);
ncstat = dap_fetch(nccomm,conn,ce,OCDATADDS,&ocroot);
nullfree(ce);
if(ncstat != NC_NOERR) {THROWCHK(ncstat); goto done;}
ncstat = buildcdftree(nccomm,ocroot,OCDATA,&dxdroot);
if(ncstat) {THROWCHK(ncstat); goto done;}
/* re-struct*/
if(!FLAGSET(nccomm->controls,NCF_UNCONSTRAINABLE)) {
ncstat = restruct(nccomm,dxdroot,nccomm->cdf.fullddsroot,
constraint->projections);
if(ncstat) {THROWCHK(ncstat); goto done;}
}
/* create the cache node */
cachenode = createnccachenode();
cachenode->isprefetch = isprefetch;
cachenode->vars = nclistclone(varlist,0);
cachenode->datadds = dxdroot;
/* Give the constraint over to the cachenode */
cachenode->constraint = constraint;
constraint = NULL;
cachenode->wholevariable = iscacheableconstraint(cachenode->constraint);
/* save the root content*/
cachenode->ocroot = ocroot;
ocstat = oc_data_getroot(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
&& nclistlength(cache->nodes) > 0) {
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,(void*)cachenode);
cache->cachesize += cachenode->xdrsize;
}
#ifdef DEBUG
fprintf(stderr,"buildcachenode: %s\n",dumpcachenode(cachenode));
#endif
done:
if(constraint != NULL) dcefree((DCEnode*)constraint);
if(cachep) *cachep = cachenode;
if(ocstat != OC_NOERR) ncstat = ocerrtoncerr(ocstat);
if(ncstat != OC_NOERR) {
freecdfroot(dxdroot);
freenccachenode(nccomm,cachenode);
if(cachep) *cachep = NULL;
}
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;
#ifdef DEBUG
fprintf(stderr,"freecachenode: %s\n",
dumpcachenode(node));
#endif
oc_data_free(nccomm->oc.conn,node->content);
dcefree((DCEnode*)node->constraint);
freecdfroot(node->datadds);
nclistfree(node->vars);
nullfree(node);
}
void
freenccache(NCDAPCOMMON* nccomm, NCcache* cache)
{
size_t 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));
if(c == NULL)
return NULL;
c->cachelimit = DFALTCACHELIMIT;
c->cachesize = 0;
c->nodes = nclistnew();
c->cachecount = DFALTCACHECOUNT;
return c;
}
static int
iscacheableprojection(DCEprojection* proj)
{
size_t i;
int cacheable;
if(proj->discrim != CES_VAR) return 0;
cacheable = 1; /* assume so */
for(i=0;i<nclistlength(proj->var->segments);i++) {
DCEsegment* segment = (DCEsegment*)nclistget(proj->var->segments,i);
if(!dapiswholesegment(segment)) {cacheable = 0; break;}
}
return cacheable;
}
static int
iscacheableconstraint(DCEconstraint* con)
{
size_t i;
if(con == NULL) return 1;
if(con->selections != NULL && nclistlength(con->selections) > 0)
return 0; /* can't deal with selections */
for(i=0;i<nclistlength(con->projections);i++) {
if(!iscacheableprojection((DCEprojection*)nclistget(con->projections,i)))
return 0;
}
return 1;
}
/*
A variable is prefetchable if
1. it is atomic
2. it's size is sufficiently small
3. it is not contained in sequence or a dimensioned structure.
*/
NCerror
markprefetch(NCDAPCOMMON* nccomm)
{
size_t i,j;
NClist* allvars = nccomm->cdf.fullddsroot->tree->varnodes;
assert(allvars != NULL);
/* mark those variables of sufficiently small size */
for(i=0;i<nclistlength(allvars);i++) {
CDFnode* var = (CDFnode*)nclistget(allvars,i);
size_t nelems;
/* If var is not atomic, then it is not prefetchable */
if(var->nctype != NC_Atomic)
continue;
/* if var is under a sequence, then never prefetch */
if(dapinsequence(var))
continue;
/* Compute the # of elements in the variable */
for(nelems=1,j=0;j<nclistlength(var->array.dimsettrans);j++) {
CDFnode* dim = (CDFnode*)nclistget(var->array.dimsettrans,j);
nelems *= dim->dim.declsize;
}
if(nelems <= nccomm->cdf.smallsizelimit
&& FLAGSET(nccomm->controls,NCF_PREFETCH)) {
var->prefetchable = 1;
if(SHOWFETCH)
{
extern char* ocfqn(OCddsnode);
char *tmp = ocfqn(var->ocnode);
nclog(NCLOGDEBUG,"prefetchable: %s=%lu",
tmp,(unsigned long)nelems);
free(tmp);
}
}
}
return NC_NOERR;
}