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common/bloom_filter: test behavior of sequences of bloom filters

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Signed-off-by: Sage Weil <sage@inktank.com>
This commit is contained in:
Sage Weil 2013-09-19 18:23:07 -07:00
parent f1584fb05c
commit fdb8b0d8ff
1 changed files with 78 additions and 0 deletions
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78
src/test/common/test_bloom_filter.cc
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@ -60,3 +60,81 @@ TEST(BloomFilter, Sweep) {
}
}
}
// test the fpp over a sequence of bloom filters, each with unique
// items inserted into it.
//
// we expect: actual_fpp = num_filters * per_filter_fpp
TEST(BloomFilter, Sequence) {
int max = 1024;
double fpp = .01;
for (int seq = 2; seq <= 128; seq *= 2) {
std::vector<bloom_filter*> ls;
for (int i=0; i<seq; i++) {
ls.push_back(new bloom_filter(max*2, fpp, i));
for (int j=0; j<max; j++) {
ls.back()->insert("ok" + stringify(j) + "_" + stringify(i));
if (ls.size() > 1)
ls[ls.size() - 2]->insert("ok" + stringify(j) + "_" + stringify(i));
}
}
int hit = 0;
int test = max * 100;
for (int i=0; i<test; ++i) {
for (std::vector<bloom_filter*>::iterator j = ls.begin(); j != ls.end(); ++j) {
if ((*j)->contains("bad" + stringify(i))) {
hit++;
break;
}
}
}
double actual = (double)hit / (double)test;
std::cout << "seq " << seq << " max " << max << " fpp " << fpp << " actual " << actual << std::endl;
}
}
// test the ffp over a sequence of bloom filters, where actual values
// are always inserted into a consecutive pair of filters. in order
// to have a false positive, we need to falsely match two consecutive
// filters.
//
// we expect: actual_fpp = num_filters * per_filter_fpp^2
TEST(BloomFilter, SequenceDouble) {
int max = 1024;
double fpp = .01;
for (int seq = 2; seq <= 128; seq *= 2) {
std::vector<bloom_filter*> ls;
for (int i=0; i<seq; i++) {
ls.push_back(new bloom_filter(max*2, fpp, i));
for (int j=0; j<max; j++) {
ls.back()->insert("ok" + stringify(j) + "_" + stringify(i));
if (ls.size() > 1)
ls[ls.size() - 2]->insert("ok" + stringify(j) + "_" + stringify(i));
}
}
int hit = 0;
int test = max * 100;
int run = 0;
for (int i=0; i<test; ++i) {
for (std::vector<bloom_filter*>::iterator j = ls.begin(); j != ls.end(); ++j) {
if ((*j)->contains("bad" + stringify(i))) {
run++;
if (run >= 2) {
hit++;
break;
}
} else {
run = 0;
}
}
}
double actual = (double)hit / (double)test;
std::cout << "seq " << seq << " max " << max << " fpp " << fpp << " actual " << actual
<< " expected " << (fpp*fpp*(double)seq) << std::endl;
}
}