Merge pull request #440 from diffix/piotr/fix-datestyle-seeding

Make datetime bucket seeding independent of `SET DateStyle =`

Author: pdobacz

src/query/anonymization.c

@@ -8,9 +8,12 @@
 #include "nodes/nodeFuncs.h"
 #include "optimizer/optimizer.h"
 #include "optimizer/tlist.h"
+#include "parser/parse_coerce.h"
 #include "parser/parse_oper.h"
 #include "parser/parsetree.h"
+#include "utils/datetime.h"
 #include "utils/fmgrprotos.h"
+#include "utils/json.h"
 #include "utils/lsyscache.h"
 
 #include "pg_diffix/aggregation/bucket_scan.h"
@@ -442,6 +445,14 @@ static hash_t hash_label(Oid type, Datum value, bool is_null)
     return hash_string(value_as_string);
   }
 
+  if (TypeCategory(type) == TYPCATEGORY_DATETIME)
+  {
+    char value_as_string[MAXDATELEN + 1];
+    /* Leveraging `json.h` as a way to get style-stable encoding of various datetime types. */
+    JsonEncodeDateTime(value_as_string, value, type, NULL);
+    return hash_string(value_as_string);
+  }
+
   /* Handle all other types by casting to text. */
   Oid type_output_funcid = InvalidOid;
   bool is_varlena = false;

test/expected/datetime.out

@@ -0,0 +1,47 @@
+LOAD 'pg_diffix';
+CREATE TABLE test_datetime (
+  id INTEGER,
+  d DATE,
+  t TIME,
+  ts TIMESTAMP WITHOUT TIME ZONE,
+  tz TIMESTAMP WITH TIME ZONE,
+  i INTERVAL
+);
+INSERT INTO test_datetime VALUES
+  (1, '2012-05-14', '14:59', '2012-05-14', '2012-05-14', '1 years'),
+  (2, '2012-05-14', '14:59', '2012-05-14', '2012-05-14', '1 years'),
+  (3, '2012-05-14', '14:59', '2012-05-14', '2012-05-14', '1 years'),
+  (4, '2012-05-14', '14:59', '2012-05-14', '2012-05-14', '1 years'),
+  (5, '2012-05-14', '14:59', '2012-05-14', '2012-05-14', '1 years'),
+  (6, '2012-05-14', '14:59', '2012-05-14', '2012-05-14', '1 years'),
+  (7, '2012-05-14', '14:59', '2012-05-14', '2012-05-14', '1 years');
+CALL diffix.mark_personal('test_datetime', 'id');
+SET ROLE diffix_test;
+SET pg_diffix.session_access_level = 'anonymized_trusted';
+----------------------------------------------------------------
+-- Sanity checks
+----------------------------------------------------------------
+SELECT diffix.access_level();
+    access_level    
+--------------------
+ anonymized_trusted
+(1 row)
+
+----------------------------------------------------------------
+-- Seeding
+----------------------------------------------------------------
+-- Datetime values are seeded the same regardless of global `datestyle` setting
+SET datestyle = 'SQL';
+SELECT ts, count(*) FROM test_datetime GROUP BY 1;
+         ts          | count 
+---------------------+-------
+ 05/14/2012 00:00:00 |     9
+(1 row)
+
+SET datestyle = 'ISO';
+SELECT ts, count(*) FROM test_datetime GROUP BY 1;
+         ts          | count 
+---------------------+-------
+ 2012-05-14 00:00:00 |     9
+(1 row)
+

test/sql/datetime.sql

@@ -0,0 +1,40 @@
+LOAD 'pg_diffix';
+
+CREATE TABLE test_datetime (
+  id INTEGER,
+  d DATE,
+  t TIME,
+  ts TIMESTAMP WITHOUT TIME ZONE,
+  tz TIMESTAMP WITH TIME ZONE,
+  i INTERVAL
+);
+
+INSERT INTO test_datetime VALUES
+  (1, '2012-05-14', '14:59', '2012-05-14', '2012-05-14', '1 years'),
+  (2, '2012-05-14', '14:59', '2012-05-14', '2012-05-14', '1 years'),
+  (3, '2012-05-14', '14:59', '2012-05-14', '2012-05-14', '1 years'),
+  (4, '2012-05-14', '14:59', '2012-05-14', '2012-05-14', '1 years'),
+  (5, '2012-05-14', '14:59', '2012-05-14', '2012-05-14', '1 years'),
+  (6, '2012-05-14', '14:59', '2012-05-14', '2012-05-14', '1 years'),
+  (7, '2012-05-14', '14:59', '2012-05-14', '2012-05-14', '1 years');
+
+CALL diffix.mark_personal('test_datetime', 'id');
+
+SET ROLE diffix_test;
+SET pg_diffix.session_access_level = 'anonymized_trusted';
+
+----------------------------------------------------------------
+-- Sanity checks
+----------------------------------------------------------------
+
+SELECT diffix.access_level();
+
+----------------------------------------------------------------
+-- Seeding
+----------------------------------------------------------------
+
+-- Datetime values are seeded the same regardless of global `datestyle` setting
+SET datestyle = 'SQL';
+SELECT ts, count(*) FROM test_datetime GROUP BY 1;
+SET datestyle = 'ISO';
+SELECT ts, count(*) FROM test_datetime GROUP BY 1;