MDEV-13446 fts_create_doc_id() unnecessarily allocates 8 bytes for every inserted row

fts_create_doc_id(): Remove.

row_mysql_convert_row_to_innobase(): Implement the logic of
fts_create_doc_id(). Reuse a buffer for the hidden FTS_DOC_ID.

row_get_prebuilt_insert_row(): Allocate a buffer for the hidden
FTS_DOC_ID at the end of prebuilt->ins_upd_rec_buff.

1 files changed, 29 insertions, 4 deletions

diff --git a/storage/xtradb/row/row0mysql.cc b/storage/xtradb/row/row0mysql.cc
index eca26ce9763..ebdee381713 100644
--- a/storage/xtradb/row/row0mysql.cc
+++ b/storage/xtradb/row/row0mysql.cc
@@ -567,11 +567,33 @@ next_column:
 
 	/* If there is a FTS doc id column and it is not user supplied (
 	generated by server) then assign it a new doc id. */
-	if (prebuilt->table->fts) {
+	if (!prebuilt->table->fts) {
+		return;
+	}
+
+	ut_a(prebuilt->table->fts->doc_col != ULINT_UNDEFINED);
 
-		ut_a(prebuilt->table->fts->doc_col != ULINT_UNDEFINED);
+	doc_id_t	doc_id;
 
-		fts_create_doc_id(prebuilt->table, row, prebuilt->heap);
+	if (!DICT_TF2_FLAG_IS_SET(prebuilt->table, DICT_TF2_FTS_HAS_DOC_ID)) {
+		if (prebuilt->table->fts->cache->first_doc_id
+		    == FTS_NULL_DOC_ID) {
+			fts_get_next_doc_id(prebuilt->table, &doc_id);
+		}
+		return;
+	}
+
+	dfield_t*	fts_doc_id = dtuple_get_nth_field(
+		row, prebuilt->table->fts->doc_col);
+
+	if (fts_get_next_doc_id(prebuilt->table, &doc_id) == DB_SUCCESS) {
+		ut_a(doc_id != FTS_NULL_DOC_ID);
+		ut_ad(sizeof(doc_id) == fts_doc_id->type.len);
+		dfield_set_data(fts_doc_id, prebuilt->ins_upd_rec_buff
+				+ prebuilt->mysql_row_len, 8);
+		fts_write_doc_id(fts_doc_id->data, doc_id);
+	} else {
+		dfield_set_null(fts_doc_id);
 	}
 }
 
@@ -1045,7 +1067,10 @@ row_get_prebuilt_insert_row(
 		prebuilt->ins_upd_rec_buff = static_cast<byte*>(
 			mem_heap_alloc(
 				prebuilt->heap,
-				prebuilt->mysql_row_len));
+				DICT_TF2_FLAG_IS_SET(prebuilt->table,
+						     DICT_TF2_FTS_HAS_DOC_ID)
+				? prebuilt->mysql_row_len + 8/* FTS_DOC_ID */
+				: prebuilt->mysql_row_len));
 	}
 
 	dtuple_t*	row;