Remove dead code for pushing down LIMIT to InnoDB FULLTEXT INDEX queries

MySQL 5.7 added code to push down the LIMIT to fulltext search in InnoDB: commit 2cd0ebf97e1b265e2282d7ceb5d8dfb663ffc48f Author: Thirunarayanan Balathandayuthapani <thirunarayanan.balathandayuth@oracle.com> Date: Fri May 27 13:49:28 2016 +0530 Bug #22709692 FTS QUERY EXCEEDS RESULT CACHE LIMIT The code was disabled when MySQL 5.7.9 was merged to MariaDB 10.2.2. We shall remove the disabled code and unnecessary variables.

Author: dr-m

storage/innobase/fts/fts0que.cc

@@ -149,13 +149,6 @@ struct fts_query_t {
 boolmulti_exist;/*!< multiple FTS_EXIST oper */
 
 st_mysql_ftparser*	parser;/*!< fts plugin parser */
-
-/** limit value for the fts query */
-ulonglong	limit;
-
-/** number of docs fetched by query. This is to restrict the
-result with limit value */
-ulonglong	n_docs;
 };
 
 /** For phrase matching, first we collect the documents and the positions
@@ -3228,11 +3221,6 @@ fts_query_filter_doc_ids(
 ulint	decoded = 0;
 ib_rbt_t*	doc_freqs = word_freq->doc_freqs;
 
-if (query->limit != ULONG_UNDEFINED
- && query->n_docs >= query->limit) {
-return(DB_SUCCESS);
-}
-
 /* Decode the ilist and add the doc ids to the query doc_id set. */
 while (decoded < len) {
 ulint	freq = 0;
@@ -3320,17 +3308,11 @@ fts_query_filter_doc_ids(
 /* Add the word to the document's matched RB tree. */
 fts_query_add_word_to_document(query, doc_id, word);
 }
-
-if (query->limit != ULONG_UNDEFINED
- && query->limit <= ++query->n_docs) {
-goto func_exit;
-}
 }
 
 /* Some sanity checks. */
 ut_a(doc_id == node->last_doc_id);
 
-func_exit:
 if (query->total_size > fts_result_cache_limit) {
 return(DB_FTS_EXCEED_RESULT_CACHE_LIMIT);
 } else {
@@ -3941,7 +3923,6 @@ fts_query_can_optimize(
 @param[in]	query_str	FTS query
 @param[in]	query_len	FTS query string len in bytes
 @param[in,out]	result	result doc ids
-@param[in]	limit	limit value
 @return DB_SUCCESS if successful otherwise error code */
 dberr_t
 fts_query(
@@ -3950,8 +3931,7 @@ fts_query(
 uint	flags,
 const byte*	query_str,
 ulint	query_len,
-fts_result_t**	result,
-ulonglong	limit)
+fts_result_t**	result)
 {
 fts_query_tquery;
 dberr_terror = DB_SUCCESS;
@@ -4013,10 +3993,6 @@ fts_query(
 
 query.total_docs = dict_table_get_n_rows(index->table);
 
-query.limit = limit;
-
-query.n_docs = 0;
-
 query.fts_common_table.suffix = "DELETED";
 
 /* Read the deleted doc_ids, we need these for filtering. */
@@ -4078,19 +4054,6 @@ fts_query(
  fts_result_cache_limit = 2048;
 );
 
-/* Optimisation is allowed for limit value
-when
-i) No ranking involved
-ii) Only FTS Union operations involved. */
-if (query.limit != ULONG_UNDEFINED
- && !fts_ast_node_check_union(ast)) {
-query.limit = ULONG_UNDEFINED;
-}
-
-DBUG_EXECUTE_IF("fts_union_limit_off",
-query.limit = ULONG_UNDEFINED;
-);
-
 /* Traverse the Abstract Syntax Tree (AST) and execute
 the query. */
 query.error = fts_ast_visit(

storage/innobase/handler/ha_innodb.cc

@@ -10537,10 +10537,8 @@ ha_innobase::ft_init_ext(
 const byte*	q = reinterpret_cast<const byte*>(
 const_cast<char*>(query));
 
-// JAN: TODO: support for ft_init_ext_with_hints(), remove the line below
-m_prebuilt->m_fts_limit= ULONG_UNDEFINED;
-dberr_t	error = fts_query(trx, index, flags, q, query_len, &result,
- m_prebuilt->m_fts_limit);
+// FIXME: support ft_init_ext_with_hints(), pass LIMIT
+dberr_t	error = fts_query(trx, index, flags, q, query_len, &result);
 
 if (error != DB_SUCCESS) {
 my_error(convert_error_code_to_mysql(error, 0, NULL), MYF(0));

storage/innobase/include/fts0fts.h

@@ -579,7 +579,6 @@ fts_commit(
 @param[in]	query_str	FTS query
 @param[in]	query_len	FTS query string len in bytes
 @param[in,out]	result	result doc ids
-@param[in]	limit	limit value
 @return DB_SUCCESS if successful otherwise error code */
 dberr_t
 fts_query(
@@ -588,8 +587,7 @@ fts_query(
 uint	flags,
 const byte*	query_str,
 ulint	query_len,
-fts_result_t**	result,
-ulonglong	limit)
+fts_result_t**	result)
 MY_ATTRIBUTE((warn_unused_result));
 
 /******************************************************************//**

storage/innobase/include/row0mysql.h

@@ -844,9 +844,6 @@ struct row_prebuilt_t {
 
 /** The MySQL table object */
 TABLE*m_mysql_table;
-
-/** limit value to avoid fts result overflow */
-ulonglongm_fts_limit;
 };
 
 /** Callback for row_mysql_sys_index_iterate() */