Revert old UUID hash used for partition ID.

src/Common/FieldVisitors.h

@@ -269,6 +269,18 @@ public:
     void operator() (const AggregateFunctionStateData & x) const;
 };
 
+/// This is a special visitor which is used to get partition ID.
+/// Calculate hash for UUID the same way as for UInt128.
+/// It worked this way until 21.5, and we cannot change it,
+/// or partition ID will be different in case UUID is used in partiton key.
+/// (It is not recommended to use UUID as partition key).
+class LegacyFieldVisitorHash : public FieldVisitorHash
+{
+public:
+    using FieldVisitorHash::FieldVisitorHash;
+    void operator() (const UUID & x) const { FieldVisitorHash::operator()(x.toUnderType()); }
+};
+
 
 template <typename T> constexpr bool isDecimalField() { return false; }
 template <> constexpr bool isDecimalField<DecimalField<Decimal32>>() { return true; }

src/Storages/MergeTree/MergeTreePartition.cpp

@@ -74,7 +74,7 @@ String MergeTreePartition::getID(const Block & partition_key_sample) const
     }
 
     SipHash hash;
-    FieldVisitorHash hashing_visitor(hash);
+    LegacyFieldVisitorHash hashing_visitor(hash);
     for (const Field & field : value)
         applyVisitor(hashing_visitor, field);
 

tests/queries/0_stateless/01891_partition_hash.reference

@@ -0,0 +1 @@
+6ba51fa36c625adab5d58007c96e32bf

tests/queries/0_stateless/01891_partition_hash.sql

@@ -0,0 +1,7 @@
+drop table if exists tab;
+create table tab (i8 Int8, i16 Int16, i32 Int32, i64 Int64, i128 Int128, i256 Int256, u8 UInt8, u16 UInt16, u32 UInt32, u64 UInt64, u128 UInt128, u256 UInt256, id UUID, s String, fs FixedString(33), a Array(UInt8), t Tuple(UInt16, UInt32), d Date, dt DateTime, dt64 DateTime64, dec128 Decimal128(3), dec256 Decimal256(4), lc LowCardinality(String)) engine = MergeTree PARTITION BY (i8, i16, i32, i64, i128, i256, u8, u16, u32, u64, u128, u256, id, s, fs, a, t, d, dt, dt64, dec128, dec256, lc) order by tuple();
+insert into tab values (-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, '61f0c404-5cb3-11e7-907b-a6006ad3dba0', 'a', 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa', [1, 2, 3], (-1, -2), '2020-01-01', '2020-01-01 01:01:01', '2020-01-01 01:01:01', '123.456', '78.9101', 'a');
+-- Here we check that partition id did not change.
+-- Different result means Backward Incompatible Change. Old partitions will not be accepted by new server.
+select partition_id from system.parts where table = 'tab' and database = currentDatabase();
+drop table if exists tab;

tests/queries/0_stateless/01891_partition_hash_no_long_int.reference

@@ -0,0 +1 @@
+04a875063d3809312ff884e90a5b4dad

tests/queries/0_stateless/01891_partition_hash_no_long_int.sql

@@ -0,0 +1,7 @@
+drop table if exists tab;
+create table tab (i8 Int8, i16 Int16, i32 Int32, i64 Int64, u8 UInt8, u16 UInt16, u32 UInt32, u64 UInt64, id UUID, s String, fs FixedString(33), a Array(UInt8), t Tuple(UInt16, UInt32), d Date, dt DateTime, dt64 DateTime64, dec128 Decimal128(3), lc LowCardinality(String)) engine = MergeTree PARTITION BY (i8, i16, i32, i64, u8, u16, u32, u64, id, s, fs, a, t, d, dt, dt64, dec128, lc) order by tuple();
+insert into tab values (-1, -1, -1, -1, -1, -1, -1, -1, '61f0c404-5cb3-11e7-907b-a6006ad3dba0', 'a', 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa', [1, 2, 3], (-1, -2), '2020-01-01', '2020-01-01 01:01:01', '2020-01-01 01:01:01', '123.456', 'a');
+-- Here we check that partition id did not change.
+-- Different result means Backward Incompatible Change. Old partitions will not be accepted by new server.
+select partition_id from system.parts where table = 'tab' and database = currentDatabase();
+drop table if exists tab;