diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/commands/analyze.c | 20 |
1 files changed, 9 insertions, 11 deletions
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c index b0c65650ee7..44a4b3ff1e3 100644 --- a/src/backend/commands/analyze.c +++ b/src/backend/commands/analyze.c @@ -2133,14 +2133,13 @@ compute_distinct_stats(VacAttrStatsP stats, } else { - double ndistinct = stats->stadistinct; + /* d here is the same as d in the Haas-Stokes formula */ + int d = nonnull_cnt - summultiple + nmultiple; double avgcount, mincount; - if (ndistinct < 0) - ndistinct = -ndistinct * totalrows; - /* estimate # of occurrences in sample of a typical value */ - avgcount = (double) samplerows / ndistinct; + /* estimate # occurrences in sample of a typical nonnull value */ + avgcount = (double) nonnull_cnt / (double) d; /* set minimum threshold count to store a value */ mincount = avgcount * 1.25; if (mincount < 2) @@ -2494,21 +2493,20 @@ compute_scalar_stats(VacAttrStatsP stats, } else { - double ndistinct = stats->stadistinct; + /* d here is the same as d in the Haas-Stokes formula */ + int d = ndistinct + toowide_cnt; double avgcount, mincount, maxmincount; - if (ndistinct < 0) - ndistinct = -ndistinct * totalrows; - /* estimate # of occurrences in sample of a typical value */ - avgcount = (double) samplerows / ndistinct; + /* estimate # occurrences in sample of a typical nonnull value */ + avgcount = (double) values_cnt / (double) d; /* set minimum threshold count to store a value */ mincount = avgcount * 1.25; if (mincount < 2) mincount = 2; /* don't let threshold exceed 1/K, however */ - maxmincount = (double) samplerows / (double) num_bins; + maxmincount = (double) values_cnt / (double) num_bins; if (mincount > maxmincount) mincount = maxmincount; if (num_mcv > track_cnt) |