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PFSELFTEST improved with sparse encoding checks.

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This commit is contained in:
antirez 2014-04-15 10:10:38 +02:00
parent dde8dff73f
commit d541f65d66
1 changed files with 29 additions and 4 deletions
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33
src/hyperloglog.c
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@ -1258,7 +1258,8 @@ void pfmergeCommand(redisClient *c) {
void pfselftestCommand(redisClient *c) {
int j, i;
sds bitcounters = sdsnewlen(NULL,HLL_DENSE_SIZE);
struct hllhdr *hdr = (struct hllhdr*) bitcounters;
struct hllhdr *hdr = (struct hllhdr*) bitcounters, *hdr2;
robj *o = NULL;
uint8_t bytecounters[HLL_REGISTERS];
/* Test 1: access registers.
@ -1289,20 +1290,43 @@ void pfselftestCommand(redisClient *c) {
}
/* Test 2: approximation error.
* The test is adds unique elements and check that the estimated value
* The test adds unique elements and check that the estimated value
* is always reasonable bounds.
*
* We check that the error is smaller than 4 times than the expected
* standard error, to make it very unlikely for the test to fail because
* of a "bad" run. */
* of a "bad" run.
*
* The test is performed with both dense and sparse HLLs at the same
* time also verifying that the computed cardinality is the same. */
memset(hdr->registers,0,HLL_DENSE_SIZE-HLL_HDR_SIZE);
o = createHLLObject();
double relerr = 1.04/sqrt(HLL_REGISTERS);
int64_t checkpoint = 1000;
int64_t checkpoint = 1;
uint64_t seed = (uint64_t)rand() | (uint64_t)rand() << 32;
uint64_t ele;
for (j = 1; j <= 10000000; j++) {
ele = j ^ seed;
hllDenseAdd(hdr->registers,(unsigned char*)&ele,sizeof(ele));
hllAdd(o,(unsigned char*)&ele,sizeof(ele));
/* Make sure that for small cardinalities we use sparse
* encoding. */
if (j == checkpoint && j < HLL_SPARSE_MAX/2) {
hdr2 = o->ptr;
if (hdr2->encoding != HLL_SPARSE) {
addReplyError(c, "TESTFAILED sparse encoding not used");
goto cleanup;
}
}
/* Check that dense and sparse representations agree. */
if (j == checkpoint && hllCount(hdr,NULL) != hllCount(o->ptr,NULL)) {
addReplyError(c, "TESTFAILED dense/sparse disagree");
goto cleanup;
}
/* Check error. */
if (j == checkpoint) {
int64_t abserr = checkpoint - (int64_t)hllCount(hdr,NULL);
if (abserr < 0) abserr = -abserr;
@ -1322,6 +1346,7 @@ void pfselftestCommand(redisClient *c) {
cleanup:
sdsfree(bitcounters);
if (o) decrRefCount(o);
}
/* PFDEBUG <subcommand> <key> ... args ...