aggregateStatistics
public AggregateStatisticsResponse aggregateStatistics(AggregateStatisticsRequest request) throws GPUdbException Calculates the requested statistics of the given column(s) in a given table.The available statistics are:
COUNT(number of total objects),MEAN,STDV(standard deviation),VARIANCE,SKEW,KURTOSIS,SUM,MIN,MAX,WEIGHTED_AVERAGE,CARDINALITY(unique count),ESTIMATED_CARDINALITY,PERCENTILE, andPERCENTILE_RANK.Estimated cardinality is calculated by using the hyperloglog approximation technique.
Percentiles and percentile ranks are approximate and are calculated using the t-digest algorithm. They must include the desired
PERCENTILE/PERCENTILE_RANK. To compute multiple percentiles each value must be specified separately (i.e. ‘percentile(75.0),percentile(99.0),percentile_rank(1234.56),percentile_rank(-5)’).A second, comma-separated value can be added to the
PERCENTILEstatistic to calculate percentile resolution, e.g., a 50th percentile with 200 resolution would be ‘percentile(50,200)’.The weighted average statistic requires a weight column to be specified in
WEIGHT_COLUMN_NAME. The weighted average is then defined as the sum of the products ofcolumnNametimes theWEIGHT_COLUMN_NAMEvalues divided by the sum of theWEIGHT_COLUMN_NAMEvalues.Additional columns can be used in the calculation of statistics via
ADDITIONAL_COLUMN_NAMES. Values in these columns will be included in the overall aggregate calculation—individual aggregates will not be calculated per additional column. For instance, requesting theCOUNTandMEANofcolumnNamex andADDITIONAL_COLUMN_NAMESy and z, where x holds the numbers 1-10, y holds 11-20, and z holds 21-30, would return the total number of x, y, and z values (30), and the single average value across all x, y, and z values (15.5).The response includes a list of key/value pairs of each statistic requested and its corresponding value.
Parameters:request-Requestobject containing the parameters for the operation.Returns:Responseobject containing the results of the operation.Throws:GPUdbException- if an error occurs during the operation.aggregateStatistics
public AggregateStatisticsResponse aggregateStatistics(String tableName, String columnName, String stats, Map<String, String> options) throws GPUdbException Calculates the requested statistics of the given column(s) in a given table.The available statistics are:
COUNT(number of total objects),MEAN,STDV(standard deviation),VARIANCE,SKEW,KURTOSIS,SUM,MIN,MAX,WEIGHTED_AVERAGE,CARDINALITY(unique count),ESTIMATED_CARDINALITY,PERCENTILE, andPERCENTILE_RANK.Estimated cardinality is calculated by using the hyperloglog approximation technique.
Percentiles and percentile ranks are approximate and are calculated using the t-digest algorithm. They must include the desired
PERCENTILE/PERCENTILE_RANK. To compute multiple percentiles each value must be specified separately (i.e. ‘percentile(75.0),percentile(99.0),percentile_rank(1234.56),percentile_rank(-5)’).A second, comma-separated value can be added to the
PERCENTILEstatistic to calculate percentile resolution, e.g., a 50th percentile with 200 resolution would be ‘percentile(50,200)’.The weighted average statistic requires a weight column to be specified in
WEIGHT_COLUMN_NAME. The weighted average is then defined as the sum of the products ofcolumnNametimes theWEIGHT_COLUMN_NAMEvalues divided by the sum of theWEIGHT_COLUMN_NAMEvalues.Additional columns can be used in the calculation of statistics via
ADDITIONAL_COLUMN_NAMES. Values in these columns will be included in the overall aggregate calculation—individual aggregates will not be calculated per additional column. For instance, requesting theCOUNTandMEANofcolumnNamex andADDITIONAL_COLUMN_NAMESy and z, where x holds the numbers 1-10, y holds 11-20, and z holds 21-30, would return the total number of x, y, and z values (30), and the single average value across all x, y, and z values (15.5).The response includes a list of key/value pairs of each statistic requested and its corresponding value.
Parameters:tableName- Name of the table on which the statistics operation will be performed, in [schema_name.]table_name format, using standard name resolution rules.columnName- Name of the primary column for which the statistics are to be calculated.stats- Comma separated list of the statistics to calculate, e.g. “sum,mean”. Supported values:COUNT: Number of objects (independent of the given column(s)).MEAN: Arithmetic mean (average), equivalent to sum/count.STDV: Sample standard deviation (denominator is count-1).VARIANCE: Unbiased sample variance (denominator is count-1).SKEW: Skewness (third standardized moment).KURTOSIS: Kurtosis (fourth standardized moment).SUM: Sum of all values in the column(s).MIN: Minimum value of the column(s).MAX: Maximum value of the column(s).WEIGHTED_AVERAGE: Weighted arithmetic mean (using the optionWEIGHT_COLUMN_NAMEas the weighting column).CARDINALITY: Number of unique values in the column(s).ESTIMATED_CARDINALITY: Estimate (via hyperloglog technique) of the number of unique values in the column(s).PERCENTILE: Estimate (via t-digest) of the given percentile of the column(s) (percentile(50.0) will be an approximation of the median). Add a second, comma-separated value to calculate percentile resolution, e.g., ‘percentile(75,150)’.PERCENTILE_RANK: Estimate (via t-digest) of the percentile rank of the given value in the column(s) (if the given value is the median of the column(s), percentile_rank(<median>) will return approximately 50.0).
options- Optional parameters.ADDITIONAL_COLUMN_NAMES: A list of comma separated column names over which statistics can be accumulated along with the primary column. All columns listed andcolumnNamemust be of the same type. Must not include the column specified incolumnNameand no column can be listed twice.WEIGHT_COLUMN_NAME: Name of column used as weighting attribute for the weighted average statistic.
Map.Returns:Responseobject containing the results of the operation.Throws:GPUdbException- if an error occurs during the operation.