cartodb4/cartodb-postgresql
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Merge pull request #246 from CartoDB/245-categories-mode

Browse Source 
Use the mode to aggregate category columns in overviews
This commit is contained in:
Javier Goizueta 2016-04-27 18:16:05 +02:00
commit 8302f89413
1 changed files with 85 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

91
scripts-available/CDB_Overviews.sql
View File

@ -88,6 +88,26 @@ AS $$
END;
$$ LANGUAGE PLPGSQL IMMUTABLE;
CREATE OR REPLACE FUNCTION _CDB_OverviewBaseTable(overview_table REGCLASS)
RETURNS REGCLASS
AS $$
DECLARE
table_name TEXT;
schema_name TEXT;
base_name TEXT;
base_table REGCLASS;
BEGIN
SELECT * FROM _cdb_split_table_name(overview_table) INTO schema_name, table_name;
base_name := _CDB_OverviewBaseTableName(table_name);
IF base_name != table_name THEN
base_table := Format('%I.%I', schema_name, base_name)::regclass;
ELSE
base_table := overview_table;
END IF;
RETURN base_table;
END;
$$ LANGUAGE PLPGSQL IMMUTABLE;
-- Schema and relation names of a table given its reloid
-- Scope: private.
-- Parameters
@ -531,6 +551,54 @@ AS $$
);
$$ LANGUAGE SQL STABLE;
CREATE OR REPLACE FUNCTION _cdb_categorical_column(reloid REGCLASS, col_name TEXT)
RETURNS BOOLEAN
AS $$
DECLARE
schema_name TEXT;
table_name TEXT;
available BOOLEAN;
categorical BOOLEAN;
BEGIN
SELECT * FROM _cdb_split_table_name(reloid) INTO schema_name, table_name;
SELECT n_distinct IS NOT NULL
FROM pg_stats
WHERE pg_stats.schemaname = schema_name
AND pg_stats.tablename = table_name
AND pg_stats.attname = col_name
INTO available;
IF available IS NULL OR NOT available THEN
EXECUTE Format('ANALYZE %s;', reloid);
END IF;
SELECT n_distinct > 0 AND n_distinct <= 20
FROM pg_stats
WHERE pg_stats.schemaname = schema_name
AND pg_stats.tablename = table_name
AND pg_stats.attname = col_name
INTO categorical;
RETURN categorical;
END;
$$ LANGUAGE PLPGSQL VOLATILE;
CREATE OR REPLACE FUNCTION _cdb_mode_of_array(anyarray)
RETURNS anyelement AS
$$
SELECT a
FROM unnest($1) a
GROUP BY 1
ORDER BY COUNT(1) DESC, 1
LIMIT 1;
$$
LANGUAGE SQL IMMUTABLE;
-- Tell Postgres how to use our aggregate
CREATE AGGREGATE _cdb_mode(anyelement) (
SFUNC=array_append,
STYPE=anyarray,
FINALFUNC=_cdb_mode_of_array,
INITCOND='{}'
);
-- SQL Aggregation expression for a datase attribute
-- Scope: private.
-- Parameters
@ -548,6 +616,7 @@ DECLARE
has_counter_column BOOLEAN;
feature_count TEXT;
total_feature_count TEXT;
base_table REGCLASS;
BEGIN
IF table_alias <> '' THEN
qualified_column := Format('%I.%I', table_alias, column_name);
@ -568,20 +637,30 @@ BEGIN
total_feature_count := 'count(*)';
END IF;
base_table := _CDB_OverviewBaseTable(reloid);
CASE column_type
WHEN 'double precision', 'real', 'integer', 'bigint', 'numeric' THEN
IF column_name = '_feature_count' THEN
RETURN 'SUM(_feature_count)';
ELSE
RETURN Format('SUM(%s*%s)/%s::' || column_type, qualified_column, feature_count, total_feature_count);
IF column_type = 'integer' AND _cdb_categorical_column(base_table, column_name) THEN
RETURN Format('CDB_Math_Mode(%s)::', qualified_column) || column_type;
ELSE
RETURN Format('SUM(%s*%s)/%s::' || column_type, qualified_column, feature_count, total_feature_count);
END IF;
END IF;
WHEN 'text', 'character varying', 'character' THEN
IF _cdb_unlimited_text_column(reloid, column_name) THEN
-- TODO: this should not be applied to columns containing largish text;
-- it is intended only to short names/identifiers
RETURN 'CASE WHEN count(distinct ' || qualified_column || ') = 1 THEN MIN(' || qualified_column || ') WHEN ' || total_feature_count || ' < 5 THEN string_agg(distinct ' || qualified_column || ','' / '') ELSE ''*'' END::' || column_type;
IF _cdb_categorical_column(base_table, column_name) THEN
RETURN Format('_cdb_mode(%s)::', qualified_column) || column_type;
ELSE
RETURN 'CASE count(*) WHEN 1 THEN MIN(' || qualified_column || ') ELSE NULL END::' || column_type;
IF _cdb_unlimited_text_column(base_table, column_name) THEN
-- TODO: this should not be applied to columns containing largish text;
-- it is intended only to short names/identifiers
RETURN 'CASE WHEN count(distinct ' || qualified_column || ') = 1 THEN MIN(' || qualified_column || ') WHEN ' || total_feature_count || ' < 5 THEN string_agg(distinct ' || qualified_column || ','' / '') ELSE ''*'' END::' || column_type;
ELSE
RETURN 'CASE count(*) WHEN 1 THEN MIN(' || qualified_column || ') ELSE NULL END::' || column_type;
END IF;
END IF;
WHEN 'boolean' THEN
RETURN 'CASE count(*) WHEN 1 THEN BOOL_AND(' || qualified_column || ') ELSE NULL END::' || column_type;