test_bloomfilter.c File Reference

#include "postgres.h"
#include "common/pg_prng.h"
#include "fmgr.h"
#include "lib/bloomfilter.h"
#include "miscadmin.h"

Include dependency graph for test_bloomfilter.c:

Go to the source code of this file.

Macros
#define	MAX_ELEMENT_BYTES   21
#define	FPOSITIVE_THRESHOLD   0.01

Functions
static void	populate_with_dummy_strings (bloom_filter *filter, int64 nelements)
static int64	nfalsepos_for_missing_strings (bloom_filter *filter, int64 nelements)
static void	create_and_test_bloom (int power, int64 nelements, int callerseed)
	PG_FUNCTION_INFO_V1 (test_bloomfilter)
Datum	test_bloomfilter (PG_FUNCTION_ARGS)

Variables
	PG_MODULE_MAGIC

Macro Definition Documentation

FPOSITIVE_THRESHOLD

#define FPOSITIVE_THRESHOLD   0.01

Definition at line 25 of file test_bloomfilter.c.

MAX_ELEMENT_BYTES

#define MAX_ELEMENT_BYTES   21

Definition at line 23 of file test_bloomfilter.c.

Function Documentation

create_and_test_bloom()

static void create_and_test_bloom ( int  power, int64  nelements, int  callerseed  )

static

Definition at line 72 of file test_bloomfilter.c.

{
    int         bloom_work_mem;
    uint64      seed;
    int64       nfalsepos;
    bloom_filter *filter;
 
    bloom_work_mem = ((int64) 1 << power) / (8 * 1024);
 
    elog(DEBUG1, "bloom_work_mem (KB): %d", bloom_work_mem);
 
    /*
     * Generate random seed, or use caller's.  Seed should always be a
     * positive value less than or equal to PG_INT32_MAX, to ensure that any
     * random seed can be recreated through callerseed if the need arises.
     */
    seed = callerseed < 0 ? pg_prng_int32p(&pg_global_prng_state) : callerseed;
 
    /* Create Bloom filter, populate it, and report on false positive rate */
    filter = bloom_create(nelements, bloom_work_mem, seed);
    populate_with_dummy_strings(filter, nelements);
    nfalsepos = nfalsepos_for_missing_strings(filter, nelements);
 
    ereport((nfalsepos > nelements * FPOSITIVE_THRESHOLD) ? WARNING : DEBUG1,
            (errmsg_internal("seed: " UINT64_FORMAT " false positives: " INT64_FORMAT " (%.6f%%) bitset %.2f%% set",
                             seed, nfalsepos, (double) nfalsepos / nelements,
                             100.0 * bloom_prop_bits_set(filter))));
 
    bloom_free(filter);
}

References bloom_create(), bloom_free(), bloom_prop_bits_set(), DEBUG1, elog, ereport, errmsg_internal(), FPOSITIVE_THRESHOLD, INT64_FORMAT, nfalsepos_for_missing_strings(), pg_global_prng_state, pg_prng_int32p(), populate_with_dummy_strings(), UINT64_FORMAT, and WARNING.

Referenced by test_bloomfilter().

nfalsepos_for_missing_strings()

static int64 nfalsepos_for_missing_strings ( bloom_filter *  filter, int64  nelements  )

static

Definition at line 52 of file test_bloomfilter.c.

{
    char        element[MAX_ELEMENT_BYTES];
    int64       nfalsepos = 0;
    int64       i;
 
    for (i = 0; i < nelements; i++)
    {
        CHECK_FOR_INTERRUPTS();
 
        snprintf(element, sizeof(element), "M" INT64_FORMAT, i);
        if (!bloom_lacks_element(filter, (unsigned char *) element,
                                 strlen(element)))
            nfalsepos++;
    }
 
    return nfalsepos;
}

References bloom_lacks_element(), CHECK_FOR_INTERRUPTS, element(), i, INT64_FORMAT, MAX_ELEMENT_BYTES, and snprintf.

Referenced by create_and_test_bloom().

PG_FUNCTION_INFO_V1()

PG_FUNCTION_INFO_V1

(

test_bloomfilter

)

populate_with_dummy_strings()

static void populate_with_dummy_strings ( bloom_filter *  filter, int64  nelements  )

static

Definition at line 32 of file test_bloomfilter.c.

{
    char        element[MAX_ELEMENT_BYTES];
    int64       i;
 
    for (i = 0; i < nelements; i++)
    {
        CHECK_FOR_INTERRUPTS();
 
        snprintf(element, sizeof(element), "i" INT64_FORMAT, i);
        bloom_add_element(filter, (unsigned char *) element, strlen(element));
    }
}

References bloom_add_element(), CHECK_FOR_INTERRUPTS, element(), i, INT64_FORMAT, MAX_ELEMENT_BYTES, and snprintf.

Referenced by create_and_test_bloom().

test_bloomfilter()

Datum test_bloomfilter

(

PG_FUNCTION_ARGS

)

Definition at line 113 of file test_bloomfilter.c.

{
    int         power = PG_GETARG_INT32(0);
    int64       nelements = PG_GETARG_INT64(1);
    int         seed = PG_GETARG_INT32(2);
    int         tests = PG_GETARG_INT32(3);
    int         i;
 
    if (power < 23 || power > 32)
        elog(ERROR, "power argument must be between 23 and 32 inclusive");
 
    if (tests <= 0)
        elog(ERROR, "invalid number of tests: %d", tests);
 
    if (nelements < 0)
        elog(ERROR, "invalid number of elements: %d", tests);
 
    for (i = 0; i < tests; i++)
    {
        elog(DEBUG1, "beginning test #%d...", i + 1);
 
        create_and_test_bloom(power, nelements, seed);
    }
 
    PG_RETURN_VOID();
}

References create_and_test_bloom(), DEBUG1, elog, ERROR, i, PG_GETARG_INT32, PG_GETARG_INT64, and PG_RETURN_VOID.

Variable Documentation

PG_MODULE_MAGIC

PG_MODULE_MAGIC

Definition at line 20 of file test_bloomfilter.c.