commit - 8078509f88c5f471da50c4a65eaa719b6114fecd
commit + 39c13db14b5db6a137e191729194d086795ea317
blob - c6a15a3997e5440d9cae04d93bb3d838d09d9a13
blob + 1460e81066d1d30a9a3fd5df72601ada747553a9
--- src/box/memtx_engine.c
+++ src/box/memtx_engine.c
@@ -1170,6 +1170,7 @@ memtx_tuple_new(struct tuple_format *format, const cha
 	tuple->format_id = tuple_format_id(format);
 	tuple_format_ref(format);
 	tuple->data_offset = data_offset;
+	tuple->is_dirty = false;
 	char *raw = (char *) tuple + tuple->data_offset;
 	field_map_build(&builder, raw - field_map_size);
 	memcpy(raw, data, tuple_len);
blob - b1f3422f1eca7d3990180178b64d3c18be767b75
blob + c9d307f50e6b18afe0b05cb977488f1b5d1a994e
--- src/box/tuple.c
+++ src/box/tuple.c
@@ -105,6 +105,7 @@ runtime_tuple_new(struct tuple_format *format, const c
 	tuple->format_id = tuple_format_id(format);
 	tuple_format_ref(format);
 	tuple->data_offset = data_offset;
+	tuple->is_dirty = false;
 	char *raw = (char *) tuple + data_offset;
 	field_map_build(&builder, raw - field_map_size);
 	memcpy(raw, data, data_len);
blob - 9a887721986c0d2efcb4a336ce409a95effdac36
blob + 4752323e495b1cec38ba9ce23e287f5a5a150cca
--- src/box/tuple.h
+++ src/box/tuple.h
@@ -319,7 +319,13 @@ struct PACKED tuple
 	/**
 	 * Offset to the MessagePack from the begin of the tuple.
 	 */
-	uint16_t data_offset;
+	uint16_t data_offset : 15;
+	/**
+	 * The tuple (if it's found in index for example) could be invisible
+	 * for current transactions. The flag means that the tuple must
+	 * be clarified by transaction engine.
+	 */
+	bool is_dirty : 1;
 	/**
 	 * Engine specific fields and offsets array concatenated
 	 * with MessagePack fields array.
@@ -1081,8 +1087,10 @@ tuple_unref(struct tuple *tuple)
 	assert(tuple->refs - 1 >= 0);
 	if (unlikely(tuple->is_bigref))
 		tuple_unref_slow(tuple);
-	else if (--tuple->refs == 0)
+	else if (--tuple->refs == 0) {
+		assert(!tuple->is_dirty);
 		tuple_delete(tuple);
+	}
 }
 
 extern struct tuple *box_tuple_last;
blob - faf038abec41d65549f92b3f3846d2fbb78b3b5e
blob + bae6c67cda44274d25a149a226cd5768238f4fea
--- src/box/tuple_format.c
+++ src/box/tuple_format.c
@@ -501,8 +501,8 @@ tuple_format_create(struct tuple_format *format, struc
 	assert(tuple_format_field(format, 0)->offset_slot == TUPLE_OFFSET_SLOT_NIL
 	       || json_token_is_multikey(&tuple_format_field(format, 0)->token));
 	size_t field_map_size = -current_slot * sizeof(uint32_t);
-	if (field_map_size > UINT16_MAX) {
-		/** tuple->data_offset is 16 bits */
+	if (field_map_size > INT16_MAX) {
+		/** tuple->data_offset is 15 bits */
 		diag_set(ClientError, ER_INDEX_FIELD_COUNT_LIMIT,
 			 -current_slot);
 		return -1;
blob - cd4dfd08906c778669bd8a79e98a348c5a960e0a
blob + ee501f81e6c73ced62d7585194a1c286c700ce22
--- src/box/vy_stmt.c
+++ src/box/vy_stmt.c
@@ -198,6 +198,7 @@ vy_stmt_alloc(struct tuple_format *format, uint32_t da
 		tuple_format_ref(format);
 	tuple->bsize = bsize;
 	tuple->data_offset = data_offset;
+	tuple->is_dirty = false;
 	vy_stmt_set_lsn(tuple, 0);
 	vy_stmt_set_type(tuple, 0);
 	vy_stmt_set_flags(tuple, 0);
blob - 11b4da39f0cf020de63256fa8d4a65f4c54f3fa8
blob + 45022cc542c868bb4b07f7f72a4175dc8379f4b6
--- test/box/huge_field_map.result
+++ test/box/huge_field_map.result
@@ -38,7 +38,7 @@ test_run:cmd("setopt delimiter ''");
 pcall(test) -- must fail but not crash
  | ---
  | - false
- | - 'Can''t create tuple: metadata size 65558 is too big'
+ | - 'Can''t create tuple: metadata size 32790 is too big'
  | ...
 
 test = nil
blob - d7971aef82a38ea07c1dba32ab8987c06a1dfb7d
blob + cb4790074df6d2cab2032805f0c5fb75cb8ce7d3
--- test/box/huge_field_map_long.result
+++ test/box/huge_field_map_long.result
@@ -40,7 +40,7 @@ test_run:cmd("setopt delimiter ''");
 pcall(test) -- must fail but not crash
  | ---
  | - false
- | - 'Can''t create tuple: metadata size 65542 is too big'
+ | - 'Can''t create tuple: metadata size 32774 is too big'
  | ...
 
 test = nil