DeleteOldStatsForColumns deletes old statistics from the system.table_statistics table.

EquiDepthHistogram creates a histogram where each bucket contains roughly the same number of samples (though it can vary when a boundary value has high frequency).

GossipTableStatAdded causes the statistic caches for this table to be invalidated.

InsertNewStat inserts a new statistic in the system table and updates the gossip key to notify the stat caches.

MakeRefresher creates a new Refresher.

NewTableStatisticsCache creates a new TableStatisticsCache that can hold statistics for <cacheSize> tables.

AutoStatsName is the name to use for statistics created automatically.

AutomaticStatisticsClusterMode controls the cluster setting for enabling automatic table statistics collection.

AutomaticStatisticsIdleTime controls the cluster setting for the fraction of time that the sampler processors will be idle when scanning large tables for automatic statistics.

DefaultAsOfTime is a duration which is used to define the AS OF time for automatic runs of CREATE STATISTICS.

DefaultRefreshInterval is the frequency at which the Refresher will check if the stats for each table should be refreshed.

HistogramData encodes the data for a histogram, which captures the distribution of values on a specific column.

JSONHistoBucket is a struct used for JSON marshaling and unmarshaling of histogram data.

JSONStatistic is a struct used for JSON marshaling and unmarshaling statistics.

Refresher is responsible for automatically refreshing the table statistics that are used by the cost-based optimizer.

SampledRow is a row that was sampled.

SampleReservoir implements reservoir sampling using random sort.

A TableStatistic object holds a statistic for a particular column or group of columns.

A TableStatisticsCache contains two underlying LRU caches: (1) A cache of []*TableStatistic objects, keyed by table ID.