vinyl: fix column mask when statement is overwritten in transaction

Statement generated by the following piece code ({1, 1, 2}) isn't dumped
to the secondary index:

    s = box.schema.space.create('test', {engine = 'vinyl'})
    s:create_index('i1', {parts = {1, 'unsigned'}})
    s:create_index('i2', {parts = {2, 'unsigned'}})

    box.begin()
    s:insert{1, 1, 1}
    s:update(1, {{'+', 3, 1}})
    box.commit()

This happens, because UPDATE is replaced with DELETE + REPLACE in the
transaction log both of which have colun_mask = 0x04 (field #3 is
updated). These statements overwrite the original INSERT in the memory
index on commit, but they are not dumped, because their column_mask does
not intersect with the column mask of the secondary index (0x02).

To avoid that, the new statement (UPDATE = DELETE + REPLACE in this
case) must inherit the column mask of the overwritten statement
(REPLACE).

Fixes #2745

src/box/vy_tx.c

@@ -824,6 +824,17 @@ vy_tx_set(struct vy_tx *tx, struct vy_index *index, struct tuple *stmt)
 		old->is_overwritten = true;
 	}
 
+	if (old != NULL && vy_stmt_type(stmt) != IPROTO_UPSERT) {
+		/*
+		 * Inherit the column mask of the overwritten statement
+		 * so as not to skip both statements on dump.
+		 */
+		uint64_t column_mask = vy_stmt_column_mask(stmt);
+		if (column_mask != UINT64_MAX)
+			vy_stmt_set_column_mask(stmt, column_mask |
+						vy_stmt_column_mask(old->stmt));
+	}
+
 	v->overwritten = old;
 	write_set_insert(&tx->write_set, v);
 	tx->write_set_version++;

test/vinyl/update_optimize.result

@@ -586,6 +586,20 @@ index:update({100}, {{'=', 6, 1}})
 ---
 - [10, 100, 1000, 10000, 100000, 1]
 ...
+box.begin()
+---
+...
+space:replace{20, 200, 2000, 20000, 200000, 2000000}
+---
+- [20, 200, 2000, 20000, 200000, 2000000]
+...
+index:update({200}, {{'=', 6, 2}})
+---
+- [20, 200, 2000, 20000, 200000, 2]
+...
+box.commit()
+---
+...
 box.snapshot()
 ---
 - ok
@@ -604,6 +618,7 @@ index:select{}
   - [4, 5, 6, 7, 8]
   - [10, 20, 30, 40, 500]
   - [10, 100, 1000, 10000, 100000, 1]
+  - [20, 200, 2000, 20000, 200000, 2]
 ...
 index2:select{}
 ---
@@ -613,6 +628,7 @@ index2:select{}
   - [30, 3, 9, 30, 4, 100]
   - [10, 20, 30, 40, 500]
   - [10, 100, 1000, 10000, 100000, 1]
+  - [20, 200, 2000, 20000, 200000, 2]
 ...
 index3:select{}
 ---
@@ -622,6 +638,7 @@ index3:select{}
   - [4, 5, 6, 7, 8]
   - [10, 20, 30, 40, 500]
   - [10, 100, 1000, 10000, 100000, 1]
+  - [20, 200, 2000, 20000, 200000, 2]
 ...
 space:drop()
 ---

test/vinyl/update_optimize.test.lua

@@ -190,6 +190,10 @@ index3:select{}
 -- dump.
 space:replace{10, 100, 1000, 10000, 100000, 1000000}
 index:update({100}, {{'=', 6, 1}})
+box.begin()
+space:replace{20, 200, 2000, 20000, 200000, 2000000}
+index:update({200}, {{'=', 6, 2}})
+box.commit()
 box.snapshot()
 index_run_count = wait_for_dump(index, index_run_count)
 old_stmt_count = dumped_stmt_count()