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cleanup statistics gathering and reporting.

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constify inputs to merge functions (so they can't call freetuple())


git-svn-id: svn+ssh://svn.corp.yahoo.com/yahoo/yrl/labs/pnuts/code/logstore@662 8dad8b1f-cf64-0410-95b6-bcf113ffbcfe
This commit is contained in:
sears 2010-03-05 19:07:47 +00:00
parent f258ce1a3f
commit 632afe6d9c
6 changed files with 158 additions and 84 deletions
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4
logserver.cpp
View file

@ -587,10 +587,6 @@ int op_stat_perf_report(pthread_data* data) {
} }
//pageid_t diskTreeComponent::build_histogram(int xid, pageid_t bucket_count, const byte **key_array, size_t * size_array) {
//
//}
int op_stat_histogram(pthread_data* data, size_t limit) { int op_stat_histogram(pthread_data* data, size_t limit) {

12
logstore.cpp
View file

@ -139,12 +139,9 @@ void logtable::flushTable()
//this is for waiting the previous merger of the mem-tree //this is for waiting the previous merger of the mem-tree
//hopefullly this wont happen //hopefullly this wont happen
printf("prv merge not complete\n");
while(get_tree_c0_mergeable()) { while(get_tree_c0_mergeable()) {
unlock(header_lock); unlock(header_lock);
// pthread_mutex_lock(mergedata->rbtree_mut);
if(tree_bytes >= max_c0_size) if(tree_bytes >= max_c0_size)
pthread_cond_wait(mergedata->input_needed_cond, mergedata->rbtree_mut); pthread_cond_wait(mergedata->input_needed_cond, mergedata->rbtree_mut);
else else
@ -168,17 +165,12 @@ void logtable::flushTable()
} }
printf("prv merge complete\n");
gettimeofday(&stop_tv,0); gettimeofday(&stop_tv,0);
stop = tv_to_double(stop_tv); stop = tv_to_double(stop_tv);
//rbtree_ptr *tmp_ptr = new rbtree_ptr_t; //(typeof(h->scratch_tree)*) malloc(sizeof(void*));
set_tree_c0_mergeable(get_tree_c0()); set_tree_c0_mergeable(get_tree_c0());
// pthread_mutex_lock(mergedata->rbtree_mut);
pthread_cond_signal(mergedata->input_ready_cond); pthread_cond_signal(mergedata->input_ready_cond);
// pthread_mutex_unlock(mergedata->rbtree_mut);
merge_count ++; merge_count ++;
set_tree_c0(new rbtree_t); set_tree_c0(new rbtree_t);
@ -190,12 +182,12 @@ void logtable::flushTable()
unlock(header_lock); unlock(header_lock);
if(first) if(first)
{ {
printf("flush waited %f sec\n", stop-start); printf("Blocked writes for %f sec\n", stop-start);
first = 0; first = 0;
} }
else else
{ {
printf("flush waited %f sec (worked %f)\n", printf("Blocked writes for %f sec (serviced writes for %f sec)\n",
stop-start, start-last_start); stop-start, start-last_start);
} }
last_start = stop; last_start = stop;

193
merger.cpp
View file

@ -4,11 +4,67 @@
#include "logiterators.cpp" #include "logiterators.cpp"
#include "datapage.h" #include "datapage.h"
typedef struct merge_stats_t {
int merge_level; // 1 => C0->C1, 2 => C1->C2
pageid_t merge_count; // This is the merge_count'th merge
struct timeval sleep; // When did we go to sleep waiting for input?
struct timeval start; // When did we wake up and start merging? (at steady state with max throughput, this should be equal to sleep)
struct timeval done; // When did we finish merging?
pageid_t bytes_out; // How many bytes did we write (including internal tree nodes)?
pageid_t num_tuples_out; // How many tuples did we write?
pageid_t num_datapages_out; // How many datapages?
pageid_t bytes_in_small; // How many bytes from the small input tree (for C0, we ignore tree overheads)?
pageid_t num_tuples_in_small; // Tuples from the small input?
pageid_t bytes_in_large; // Bytes from the large input?
pageid_t num_tuples_in_large; // Tuples from large input?
} merge_stats_t;
void merge_stats_pp(FILE* fd, merge_stats_t &stats) {
long long sleep_time = stats.start.tv_sec - stats.sleep.tv_sec;
long long work_time = stats.done.tv_sec - stats.start.tv_sec;
long long total_time = sleep_time + work_time;
double mb_out = ((double)stats.bytes_out) /(1024.0*1024.0);
double mb_ins= ((double)stats.bytes_in_small) /(1024.0*1024.0);
double mb_inl = ((double)stats.bytes_in_large) /(1024.0*1024.0);
double kt_out = ((double)stats.num_tuples_out) /(1024.0);
double kt_ins= ((double)stats.num_tuples_in_small) /(1024.0);
double kt_inl = ((double)stats.num_tuples_in_large) /(1024.0);
double mb_hdd = mb_out + mb_inl + (stats.merge_level == 1 ? 0.0 : mb_ins);
double kt_hdd = kt_out + kt_inl + (stats.merge_level == 1 ? 0.0 : kt_ins);
fprintf(fd,
"=====================================================================\n"
"Thread %d merge %lld: sleep %lld sec, run %lld sec\n"
" megabytes kTuples datapages MB/s (real) kTup/s (real)\n"
"Wrote %7lld %7lld %9lld" " %6.1f %6.1f" " %8.1f %8.1f" "\n"
"Read (small) %7lld %7lld - " " %6.1f %6.1f" " %8.1f %8.1f" "\n"
"Read (large) %7lld %7lld - " " %6.1f %6.1f" " %8.1f %8.1f" "\n"
"Disk %7lld %7lld - " " %6.1f %6.1f" " %8.1f %8.1f" "\n"
".....................................................................\n"
"avg tuple len: %6.2fkb\n"
"effective throughput: (mb/s ; nsec/byte): (%.2f; %.2f) active" "\n"
" (%.2f; %.2f) wallclock" "\n"
".....................................................................\n"
,
stats.merge_level, stats.merge_count,
sleep_time,
work_time,
(long long)mb_out, (long long)kt_out, stats.num_datapages_out, mb_out / (double)work_time, mb_out / (double)total_time, kt_out / (double)work_time, kt_out / (double)total_time,
(long long)mb_ins, (long long)kt_ins, mb_ins / (double)work_time, mb_ins / (double)total_time, kt_ins / (double)work_time, kt_ins / (double)total_time,
(long long)mb_inl, (long long)kt_inl, mb_inl / (double)work_time, mb_inl / (double)total_time, kt_inl / (double)work_time, kt_inl / (double)total_time,
(long long)mb_hdd, (long long)kt_hdd, mb_hdd / (double)work_time, mb_hdd / (double)total_time, kt_hdd / (double)work_time, kt_hdd / (double)total_time,
mb_out / kt_out,
mb_ins / work_time, 1000.0 * work_time / mb_ins, mb_ins / total_time, 1000.0 * total_time / mb_ins
);
}
double merge_stats_nsec_to_merge_in_bytes(merge_stats_t); // how many nsec did we burn on each byte from the small tree (want this to be equal for the two mergers)
inline DataPage<datatuple>* inline DataPage<datatuple>*
insertTuple(int xid, DataPage<datatuple> *dp, datatuple *t, insertTuple(int xid, DataPage<datatuple> *dp, datatuple *t,
logtable *ltable, logtable *ltable,
diskTreeComponent * ltree, diskTreeComponent * ltree, merge_stats_t*);
int64_t &dpages, int64_t &npages);
int merge_scheduler::addlogtable(logtable *ltable) int merge_scheduler::addlogtable(logtable *ltable)
{ {
@ -184,6 +240,16 @@ void merge_scheduler::startlogtable(int index, int64_t MAX_C0_SIZE)
} }
template <class ITA, class ITB>
void merge_iterators(int xid,
ITA *itrA,
ITB *itrB,
logtable *ltable,
diskTreeComponent *scratch_tree,
merge_stats_t *stats,
bool dropDeletes);
/** /**
* Merge algorithm: Outsider's view * Merge algorithm: Outsider's view
*<pre> *<pre>
@ -208,7 +274,7 @@ void merge_scheduler::startlogtable(int index, int64_t MAX_C0_SIZE)
void* memMergeThread(void*arg) void* memMergeThread(void*arg)
{ {
int xid;// = Tbegin(); int xid;
merger_args * a = (merger_args*)(arg); merger_args * a = (merger_args*)(arg);
@ -219,6 +285,10 @@ void* memMergeThread(void*arg)
while(true) // 1 while(true) // 1
{ {
merge_stats_t stats;
stats.merge_level = 1;
stats.merge_count = merge_count;
gettimeofday(&stats.sleep,0);
writelock(ltable->header_lock,0); writelock(ltable->header_lock,0);
int done = 0; int done = 0;
// 2: wait for c0_mergable // 2: wait for c0_mergable
@ -235,14 +305,14 @@ void* memMergeThread(void*arg)
break; break;
} }
printf("mmt:\twaiting for block ready cond\n"); DEBUG("mmt:\twaiting for block ready cond\n");
unlock(ltable->header_lock); unlock(ltable->header_lock);
pthread_cond_wait(a->in_block_ready_cond, a->block_ready_mut); pthread_cond_wait(a->in_block_ready_cond, a->block_ready_mut);
pthread_mutex_unlock(a->block_ready_mut); pthread_mutex_unlock(a->block_ready_mut);
writelock(ltable->header_lock,0); writelock(ltable->header_lock,0);
printf("mmt:\tblock ready\n"); DEBUG("mmt:\tblock ready\n");
} }
*a->in_block_needed = false; *a->in_block_needed = false;
@ -256,6 +326,8 @@ void* memMergeThread(void*arg)
break; break;
} }
gettimeofday(&stats.start, 0);
// 3: Begin transaction // 3: Begin transaction
xid = Tbegin(); xid = Tbegin();
@ -274,10 +346,9 @@ void* memMergeThread(void*arg)
unlock(ltable->header_lock); unlock(ltable->header_lock);
//: do the merge //: do the merge
printf("mmt:\tMerging:\n"); DEBUG("mmt:\tMerging:\n");
int64_t npages = 0; merge_iterators<typeof(*itrA),typeof(*itrB)>(xid, itrA, itrB, ltable, c1_prime, &stats, false);
int64_t mergedPages = merge_iterators<typeof(*itrA),typeof(*itrB)>(xid, itrA, itrB, ltable, c1_prime, npages, false);
delete itrA; delete itrA;
delete itrB; delete itrB;
@ -290,7 +361,7 @@ void* memMergeThread(void*arg)
c1_prime->get_alloc()->force_regions(xid); c1_prime->get_alloc()->force_regions(xid);
merge_count++; merge_count++;
printf("mmt:\tmerge_count %d #pages written %lld\n", merge_count, npages); DEBUG("mmt:\tmerge_count %lld #bytes written %lld\n", stats.merge_count, stats.bytes_out);
writelock(ltable->header_lock,0); writelock(ltable->header_lock,0);
@ -298,14 +369,14 @@ void* memMergeThread(void*arg)
//TODO: this is simplistic for now //TODO: this is simplistic for now
//6: if c1' is too big, signal the other merger //6: if c1' is too big, signal the other merger
double target_R = *(a->r_i); double target_R = *(a->r_i);
double new_c1_size = npages * PAGE_SIZE; double new_c1_size = stats.bytes_out;
assert(target_R >= MIN_R); assert(target_R >= MIN_R);
bool signal_c2 = (new_c1_size / ltable->max_c0_size > target_R) || bool signal_c2 = (new_c1_size / ltable->max_c0_size > target_R) ||
(a->max_size && new_c1_size > a->max_size ); (a->max_size && new_c1_size > a->max_size );
if( signal_c2 ) if( signal_c2 )
{ {
printf("mmt:\tsignaling C2 for merge\n"); DEBUG("mmt:\tsignaling C2 for merge\n");
printf("mmt:\tnew_c1_size %.2f\tMAX_C0_SIZE %lld\ta->max_size %lld\t targetr %.2f \n", new_c1_size, DEBUG("mmt:\tnew_c1_size %.2f\tMAX_C0_SIZE %lld\ta->max_size %lld\t targetr %.2f \n", new_c1_size,
ltable->max_c0_size, a->max_size, target_R); ltable->max_c0_size, a->max_size, target_R);
// XXX need to report backpressure here! Also, shouldn't be inside a transaction while waiting on backpressure. // XXX need to report backpressure here! Also, shouldn't be inside a transaction while waiting on backpressure.
@ -344,18 +415,19 @@ void* memMergeThread(void*arg)
ltable->set_tree_c1(c1_prime); ltable->set_tree_c1(c1_prime);
} }
printf("mmt:\tUpdated C1's position on disk to %lld\n",ltable->get_tree_c1()->get_root_rec().page); DEBUG("mmt:\tUpdated C1's position on disk to %lld\n",ltable->get_tree_c1()->get_root_rec().page);
// 13 // 13
ltable->update_persistent_header(xid); ltable->update_persistent_header(xid);
Tcommit(xid); Tcommit(xid);
unlock(ltable->header_lock); unlock(ltable->header_lock);
gettimeofday(&stats.done, 0);
merge_stats_pp(stdout, stats);
//TODO: get the freeing outside of the lock //TODO: get the freeing outside of the lock
} }
//pthread_mutex_unlock(a->block_ready_mut);
return 0; return 0;
} }
@ -370,11 +442,15 @@ void *diskMergeThread(void*arg)
logtable * ltable = a->ltable; logtable * ltable = a->ltable;
assert(ltable->get_tree_c2()); assert(ltable->get_tree_c2());
int merge_count =0; int merge_count =0;
//pthread_mutex_lock(a->block_ready_mut);
while(true) while(true)
{ {
merge_stats_t stats;
stats.merge_level = 2;
stats.merge_count = merge_count;
gettimeofday(&stats.sleep,0);
// 2: wait for input // 2: wait for input
writelock(ltable->header_lock,0); writelock(ltable->header_lock,0);
int done = 0; int done = 0;
@ -391,13 +467,13 @@ void *diskMergeThread(void*arg)
break; break;
} }
printf("dmt:\twaiting for block ready cond\n"); DEBUG("dmt:\twaiting for block ready cond\n");
unlock(ltable->header_lock); unlock(ltable->header_lock);
pthread_cond_wait(a->in_block_ready_cond, a->block_ready_mut); pthread_cond_wait(a->in_block_ready_cond, a->block_ready_mut);
pthread_mutex_unlock(a->block_ready_mut); pthread_mutex_unlock(a->block_ready_mut);
printf("dmt:\tblock ready\n"); DEBUG("dmt:\tblock ready\n");
writelock(ltable->header_lock,0); writelock(ltable->header_lock,0);
} }
*a->in_block_needed = false; *a->in_block_needed = false;
@ -408,7 +484,7 @@ void *diskMergeThread(void*arg)
break; break;
} }
int64_t mergedPages=0; gettimeofday(&stats.start, 0);
// 3: begin // 3: begin
xid = Tbegin(); xid = Tbegin();
@ -426,10 +502,9 @@ void *diskMergeThread(void*arg)
unlock(ltable->header_lock); unlock(ltable->header_lock);
//do the merge //do the merge
printf("dmt:\tMerging:\n"); DEBUG("dmt:\tMerging:\n");
int64_t npages = 0; merge_iterators<typeof(*itrA),typeof(*itrB)>(xid, itrA, itrB, ltable, c2_prime, &stats, true);
mergedPages = merge_iterators<typeof(*itrA),typeof(*itrB)>(xid, itrA, itrB, ltable, c2_prime, npages, true);
delete itrA; delete itrA;
delete itrB; delete itrB;
@ -458,54 +533,74 @@ void *diskMergeThread(void*arg)
merge_count++; merge_count++;
//update the current optimal R value //update the current optimal R value
*(a->r_i) = std::max(MIN_R, sqrt( (npages * 1.0) / (ltable->max_c0_size/PAGE_SIZE) ) ); *(a->r_i) = std::max(MIN_R, sqrt( (stats.bytes_out * 1.0) / (ltable->max_c0_size) ) );
printf("dmt:\tmerge_count %d\t#written pages: %lld\n optimal r %.2f", merge_count, npages, *(a->r_i)); DEBUG("dmt:\tmerge_count %lld\t#written bytes: %lld\n optimal r %.2f", stats.merge_count, stats.bytes_out, *(a->r_i));
// 10: C2 is never to big // 10: C2 is never to big
ltable->set_tree_c2(c2_prime); ltable->set_tree_c2(c2_prime);
printf("dmt:\tUpdated C2's position on disk to %lld\n",(long long)-1); DEBUG("dmt:\tUpdated C2's position on disk to %lld\n",(long long)-1);
// 13 // 13
ltable->update_persistent_header(xid); ltable->update_persistent_header(xid);
Tcommit(xid); Tcommit(xid);
unlock(ltable->header_lock); unlock(ltable->header_lock);
gettimeofday(&stats.done, 0);
merge_stats_pp(stdout, stats);
} }
return 0; return 0;
} }
template <class ITA, class ITB> template <class ITA, class ITB>
int64_t merge_iterators(int xid, void merge_iterators(int xid,
ITA *itrA, //iterator on c1 or c2 ITA *itrA, //iterator on c1 or c2
ITB *itrB, //iterator on c0 or c1, respectively ITB *itrB, //iterator on c0 or c1, respectively
logtable *ltable, logtable *ltable,
diskTreeComponent *scratch_tree, diskTreeComponent *scratch_tree, merge_stats_t *stats,
int64_t &npages,
bool dropDeletes // should be true iff this is biggest component bool dropDeletes // should be true iff this is biggest component
) )
{ {
int64_t dpages = 0; stats->bytes_out = 0;
int64_t ntuples = 0; stats->num_tuples_out = 0;
stats->bytes_in_small = 0;
stats->num_tuples_in_small = 0;
stats->bytes_in_large = 0;
stats->num_tuples_in_large = 0;
DataPage<datatuple> *dp = 0; DataPage<datatuple> *dp = 0;
datatuple *t1 = itrA->getnext(); datatuple *t1 = itrA->getnext();
if(t1) {
stats->num_tuples_in_large++;
stats->bytes_in_large += t1->byte_length();
}
datatuple *t2 = 0; datatuple *t2 = 0;
while( (t2=itrB->getnext()) != 0) while( (t2=itrB->getnext()) != 0)
{ {
stats->num_tuples_in_small++;
stats->bytes_in_small += t2->byte_length();
DEBUG("tuple\t%lld: keylen %d datalen %d\n", DEBUG("tuple\t%lld: keylen %d datalen %d\n",
ntuples, *(t2->keylen),*(t2->datalen) ); ntuples, *(t2->keylen),*(t2->datalen) );
while(t1 != 0 && datatuple::compare(t1->key(), t1->keylen(), t2->key(), t2->keylen()) < 0) // t1 is less than t2 while(t1 != 0 && datatuple::compare(t1->key(), t1->keylen(), t2->key(), t2->keylen()) < 0) // t1 is less than t2
{ {
//insert t1 //insert t1
dp = insertTuple(xid, dp, t1, ltable, scratch_tree, dp = insertTuple(xid, dp, t1, ltable, scratch_tree, stats);
dpages, npages);
datatuple::freetuple(t1); datatuple::freetuple(t1);
ntuples++; stats->num_tuples_out++;
//advance itrA //advance itrA
t1 = itrA->getnext(); t1 = itrA->getnext();
if(t1) {
stats->num_tuples_in_large++;
stats->bytes_in_large += t1->byte_length();
}
} }
if(t1 != 0 && datatuple::compare(t1->key(), t1->keylen(), t2->key(), t2->keylen()) == 0) if(t1 != 0 && datatuple::compare(t1->key(), t1->keylen(), t2->key(), t2->keylen()) == 0)
@ -514,62 +609,64 @@ int64_t merge_iterators(int xid,
//insert merged tuple, drop deletes //insert merged tuple, drop deletes
if(dropDeletes && !mtuple->isDelete()) if(dropDeletes && !mtuple->isDelete())
dp = insertTuple(xid, dp, mtuple, ltable, scratch_tree, dp = insertTuple(xid, dp, mtuple, ltable, scratch_tree, stats);
dpages, npages);
datatuple::freetuple(t1); datatuple::freetuple(t1);
t1 = itrA->getnext(); //advance itrA t1 = itrA->getnext(); //advance itrA
if(t1) {
stats->num_tuples_in_large++;
stats->bytes_in_large += t1->byte_length();
}
datatuple::freetuple(mtuple); datatuple::freetuple(mtuple);
} }
else else
{ {
//insert t2 //insert t2
dp = insertTuple(xid, dp, t2, ltable, scratch_tree, dp = insertTuple(xid, dp, t2, ltable, scratch_tree, stats);
dpages, npages);
// cannot free any tuples here; they may still be read through a lookup // cannot free any tuples here; they may still be read through a lookup
} }
datatuple::freetuple(t2); datatuple::freetuple(t2);
ntuples++; stats->num_tuples_out++;
} }
while(t1 != 0) // t1 is less than t2 while(t1 != 0) // t1 is less than t2
{ {
dp = insertTuple(xid, dp, t1, ltable, scratch_tree, dp = insertTuple(xid, dp, t1, ltable, scratch_tree, stats);
dpages, npages);
datatuple::freetuple(t1); datatuple::freetuple(t1);
ntuples++; stats->num_tuples_out++;
//advance itrA //advance itrA
t1 = itrA->getnext(); t1 = itrA->getnext();
if(t1) {
stats->num_tuples_in_large++;
stats->bytes_in_large += t1->byte_length();
}
} }
if(dp!=NULL) if(dp!=NULL)
delete dp; delete dp;
DEBUG("dpages: %d\tnpages: %d\tntuples: %d\n", dpages, npages, ntuples); DEBUG("dpages: %d\tnpages: %d\tntuples: %d\n", dpages, npages, ntuples);
return dpages;
} }
inline DataPage<datatuple>* inline DataPage<datatuple>*
insertTuple(int xid, DataPage<datatuple> *dp, datatuple *t, insertTuple(int xid, DataPage<datatuple> *dp, datatuple *t,
logtable *ltable, logtable *ltable,
diskTreeComponent * ltree, diskTreeComponent * ltree, merge_stats_t * stats)
int64_t &dpages, int64_t &npages)
{ {
if(dp==0) if(dp==0)
{ {
dp = ltable->insertTuple(xid, t, ltree); dp = ltable->insertTuple(xid, t, ltree);
dpages++; stats->num_datapages_out++;
} }
else if(!dp->append(t)) else if(!dp->append(t))
{ {
npages += dp->get_page_count(); stats->bytes_out += (PAGE_SIZE * dp->get_page_count());
delete dp; delete dp;
dp = ltable->insertTuple(xid, t, ltree); dp = ltable->insertTuple(xid, t, ltree);
dpages++; stats->num_datapages_out++;
} }
return dp; return dp;

9
merger.h
View file

@ -70,15 +70,6 @@ public:
void shutdown(); void shutdown();
}; };
template <class ITA, class ITB>
int64_t merge_iterators(int xid,
ITA *itrA,
ITB *itrB,
logtable *ltable,
diskTreeComponent *scratch_tree,
int64_t &npages,
bool dropDeletes);
void* memMergeThread(void* arg); void* memMergeThread(void* arg);
void* diskMergeThread(void* arg); void* diskMergeThread(void* arg);

7
tuplemerger.cpp
View file

@ -1,9 +1,8 @@
#include "tuplemerger.h" #include "tuplemerger.h"
#include "logstore.h" #include "logstore.h"
// XXX make the imputs 'const'
// XXX test / reason about this... // XXX test / reason about this...
datatuple* tuplemerger::merge(datatuple *t1, datatuple *t2) datatuple* tuplemerger::merge(const datatuple *t1, const datatuple *t2)
{ {
datatuple *t; datatuple *t;
if(t1->isDelete() && t2->isDelete()) { if(t1->isDelete() && t2->isDelete()) {
@ -31,7 +30,7 @@ datatuple* tuplemerger::merge(datatuple *t1, datatuple *t2)
* deletes are handled by the tuplemerger::merge function * deletes are handled by the tuplemerger::merge function
* so here neither t1 nor t2 is a delete datatuple * so here neither t1 nor t2 is a delete datatuple
**/ **/
datatuple* append_merger(datatuple *t1, datatuple *t2) datatuple* append_merger(const datatuple *t1, const datatuple *t2)
{ {
assert(!(t1->isDelete() || t2->isDelete())); assert(!(t1->isDelete() || t2->isDelete()));
len_t keylen = t1->keylen(); len_t keylen = t1->keylen();
@ -49,7 +48,7 @@ datatuple* append_merger(datatuple *t1, datatuple *t2)
* deletes are handled by the tuplemerger::merge function * deletes are handled by the tuplemerger::merge function
* so here neither t1 nor t2 is a delete datatuple * so here neither t1 nor t2 is a delete datatuple
**/ **/
datatuple* replace_merger(datatuple *t1, datatuple *t2) datatuple* replace_merger(const datatuple *t1, const datatuple *t2)
{ {
return t2->create_copy(); return t2->create_copy();
} }

9
tuplemerger.h
View file

@ -3,11 +3,10 @@
struct datatuple; struct datatuple;
typedef datatuple* (*merge_fn_t) (datatuple*, datatuple *); typedef datatuple* (*merge_fn_t) (const datatuple*, const datatuple *);
datatuple* append_merger(datatuple *t1, datatuple *t2); datatuple* append_merger(const datatuple *t1, const datatuple *t2);
datatuple* replace_merger(const datatuple *t1, const datatuple *t2);
datatuple* replace_merger(datatuple *t1, datatuple *t2);
class tuplemerger class tuplemerger
@ -21,7 +20,7 @@ public:
} }
datatuple* merge(datatuple *t1, datatuple *t2); datatuple* merge(const datatuple *t1, const datatuple *t2);
private: private: