MDEV-19051 Avoid unnecessary writing MLOG_INDEX_LOAD

1) Avoid writing of MLOG_INDEX_LOAD redo log record during inplace
alter table when the table is empty and also for spatial index.

2) Avoid creation of temporary merge file for spatial index during
index creation process.

storage/innobase/include/btr0bulk.h

 /*****************************************************************************
 
 Copyright (c) 2014, 2015, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 2019, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -284,6 +285,7 @@ class BtrBulk
 		m_trx(trx),
 		m_flush_observer(observer)
 	{
+		ut_ad(!dict_index_is_spatial(index));
 #ifdef UNIV_DEBUG
 		if (m_flush_observer)
 		fil_space_inc_redo_skipped_count(m_index->space);

storage/innobase/include/trx0trx.h

 /*****************************************************************************
 
 Copyright (c) 1996, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2015, 2018, MariaDB Corporation.
+Copyright (c) 2015, 2019, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -40,20 +40,9 @@ Created 3/26/1996 Heikki Tuuri
 
 // Forward declaration
 struct mtr_t;
-
-// Forward declaration
 class ReadView;
-
-// Forward declaration
 class FlushObserver;
-
-/** Set flush observer for the transaction
-@param[in/out]	trx		transaction struct
-@param[in]	observer	flush observer */
-void
-trx_set_flush_observer(
-	trx_t*		trx,
-	FlushObserver*	observer);
+class ut_stage_alter_t;
 
 /******************************************************************//**
 Set detailed error message for the transaction. */
@@ -1132,8 +1121,11 @@ struct trx_t {
 	/*------------------------------*/
 	char*		detailed_error;	/*!< detailed error message for last
 					error, or empty. */
-	FlushObserver*	flush_observer;	/*!< flush observer */
-
+private:
+	/** flush observer used to track flushing of non-redo logged pages
+	during bulk create index */
+	FlushObserver*	flush_observer;
+public:
 	/* Lock wait statistics */
 	ulint		n_rec_lock_waits;
 					/*!< Number of record lock waits,
@@ -1177,6 +1169,20 @@ struct trx_t {
 		return(assign_temp_rseg());
 	}
 
+	/** Set the innodb_log_optimize_ddl page flush observer
+	@param[in]	space_id	tablespace id
+	@param[in,out]	stage		performance_schema accounting */
+	void set_flush_observer(ulint space_id, ut_stage_alter_t* stage);
+
+	/** Remove the flush observer */
+	void remove_flush_observer();
+
+	/** @return the flush observer */
+	FlushObserver* get_flush_observer() const
+	{
+		return flush_observer;
+	}
+
 private:
 	/** Assign a rollback segment for modifying temporary tables.
 	@return the assigned rollback segment */

storage/innobase/row/row0ftsort.cc

@@ -1673,7 +1673,7 @@ row_fts_merge_insert(
 	/* Create bulk load instance */
 	ins_ctx.btr_bulk = UT_NEW_NOKEY(
 		BtrBulk(aux_index, trx, psort_info[0].psort_common->trx
-			->flush_observer));
+			->get_flush_observer()));
 
 	/* Create tuple for insert */
 	ins_ctx.tuple = dtuple_create(heap, dict_index_get_n_fields(aux_index));

storage/innobase/row/row0merge.cc

@@ -1736,7 +1736,6 @@ row_merge_read_clustered_index(
 	mem_heap_t*		mtuple_heap = NULL;
 	mtuple_t		prev_mtuple;
 	mem_heap_t*		conv_heap = NULL;
-	FlushObserver*		observer = trx->flush_observer;
 	double 			curr_progress = 0.0;
 	ib_uint64_t		read_rows = 0;
 	ib_uint64_t		table_total_rows = 0;
@@ -2211,9 +2210,8 @@ row_merge_read_clustered_index(
 		bool	skip_sort = skip_pk_sort
 			&& dict_index_is_clust(merge_buf[0]->index);
 
-		for (ulint i = 0; i < n_index; i++, skip_sort = false) {
+		for (ulint k = 0, i = 0; i < n_index; i++, skip_sort = false) {
 			row_merge_buf_t*	buf	= merge_buf[i];
-			merge_file_t*		file	= &files[i];
 			ulint			rows_added = 0;
 
 			if (dict_index_is_spatial(buf->index)) {
@@ -2237,6 +2235,8 @@ row_merge_read_clustered_index(
 				continue;
 			}
 
+			merge_file_t*	file = &files[k++];
+
 			if (UNIV_LIKELY
 			    (row && (rows_added = row_merge_buf_add(
 					buf, fts_index, old_table, new_table,
@@ -2244,6 +2244,15 @@ row_merge_read_clustered_index(
 					conv_heap, &err,
 					&v_heap, eval_table, trx)))) {
 
+				/* Set the page flush observer for the
+				transaction when buffering the very first
+				record for a non-redo-logged operation. */
+				if (file->n_rec == 0 && i == 0
+				    && innodb_log_optimize_ddl) {
+					trx->set_flush_observer(
+						new_table->space, stage);
+				}
+
 				/* If we are creating FTS index,
 				a single row can generate more
 				records for tokenized word */
@@ -2383,7 +2392,7 @@ row_merge_read_clustered_index(
 						clust_btr_bulk = UT_NEW_NOKEY(
 							BtrBulk(index[i],
 								trx,
-								observer/**/));
+								trx->get_flush_observer()));
 					} else {
 						clust_btr_bulk->latch();
 					}
@@ -2495,8 +2504,9 @@ row_merge_read_clustered_index(
 						trx->error_key_num = i;
 						goto all_done;);
 
-					BtrBulk	btr_bulk(index[i], trx,
-							 observer);
+					BtrBulk	btr_bulk(
+						index[i], trx,
+						trx->get_flush_observer());
 
 					err = row_merge_insert_index_tuples(
 						index[i], old_table,
@@ -4597,47 +4607,26 @@ row_merge_build_indexes(
 	}
 
 	trx_start_if_not_started_xa(trx, true);
+	ulint	n_merge_files = 0;
 
-	/* Check if we need a flush observer to flush dirty pages.
-	Since we disable redo logging in bulk load, so we should flush
-	dirty pages before online log apply, because online log apply enables
-	redo logging(we can do further optimization here).
-	1. online add index: flush dirty pages right before row_log_apply().
-	2. table rebuild: flush dirty pages before row_log_table_apply().
-
-	we use bulk load to create all types of indexes except spatial index,
-	for which redo logging is enabled. If we create only spatial indexes,
-	we don't need to flush dirty pages at all. */
-	bool	need_flush_observer = bool(innodb_log_optimize_ddl);
-
-	if (need_flush_observer) {
-		need_flush_observer = old_table != new_table;
-
-		for (i = 0; i < n_indexes; i++) {
-			if (!dict_index_is_spatial(indexes[i])) {
-				need_flush_observer = true;
-			}
+	for (ulint i = 0; i < n_indexes; i++)
+	{
+		if (!dict_index_is_spatial(indexes[i])) {
+			n_merge_files++;
 		}
 	}
 
-	FlushObserver*	flush_observer = NULL;
-	if (need_flush_observer) {
-		flush_observer = UT_NEW_NOKEY(
-			FlushObserver(new_table->space, trx, stage));
-
-		trx_set_flush_observer(trx, flush_observer);
-	}
-
 	merge_files = static_cast<merge_file_t*>(
-		ut_malloc_nokey(n_indexes * sizeof *merge_files));
+		ut_malloc_nokey(n_merge_files * sizeof *merge_files));
 
 	/* Initialize all the merge file descriptors, so that we
 	don't call row_merge_file_destroy() on uninitialized
 	merge file descriptor */
 
-	for (i = 0; i < n_indexes; i++) {
+	for (i = 0; i < n_merge_files; i++) {
 		merge_files[i].fd = -1;
 		merge_files[i].offset = 0;
+		merge_files[i].n_rec = 0;
 	}
 
 	total_static_cost = COST_BUILD_INDEX_STATIC * n_indexes + COST_READ_CLUSTERED_INDEX;
@@ -4720,7 +4709,7 @@ row_merge_build_indexes(
 				      " and create temporary files");
 	}
 
-	for (i = 0; i < n_indexes; i++) {
+	for (i = 0; i < n_merge_files; i++) {
 		total_index_blocks += merge_files[i].offset;
 	}
 
@@ -4733,7 +4722,7 @@ row_merge_build_indexes(
 	/* Now we have files containing index entries ready for
 	sorting and inserting. */
 
-	for (i = 0; i < n_indexes; i++) {
+	for (ulint k = 0, i = 0; i < n_indexes; i++) {
 		dict_index_t*	sort_idx = indexes[i];
 
 		if (dict_index_is_spatial(sort_idx)) {
@@ -4812,13 +4801,13 @@ row_merge_build_indexes(
 #ifdef FTS_INTERNAL_DIAG_PRINT
 			DEBUG_FTS_SORT_PRINT("FTS_SORT: Complete Insert\n");
 #endif
-		} else if (merge_files[i].fd >= 0) {
+		} else if (merge_files[k].fd >= 0) {
 			char	buf[NAME_LEN + 1];
 			row_merge_dup_t	dup = {
 				sort_idx, table, col_map, 0};
 
 			pct_cost = (COST_BUILD_INDEX_STATIC +
-				(total_dynamic_cost * merge_files[i].offset /
+				(total_dynamic_cost * merge_files[k].offset /
 					total_index_blocks)) /
 				(total_static_cost + total_dynamic_cost)
 				* PCT_COST_MERGESORT_INDEX * 100;
@@ -4842,7 +4831,7 @@ row_merge_build_indexes(
 			}
 
 			error = row_merge_sort(
-					trx, &dup, &merge_files[i],
+					trx, &dup, &merge_files[k],
 					block, &tmpfd, true,
 					pct_progress, pct_cost,
 					crypt_block, new_table->space, stage);
@@ -4864,10 +4853,10 @@ row_merge_build_indexes(
 
 			if (error == DB_SUCCESS) {
 				BtrBulk	btr_bulk(sort_idx, trx,
-						 flush_observer);
+						 trx->get_flush_observer());
 
 				pct_cost = (COST_BUILD_INDEX_STATIC +
-					(total_dynamic_cost * merge_files[i].offset /
+					(total_dynamic_cost * merge_files[k].offset /
 						total_index_blocks)) /
 					(total_static_cost + total_dynamic_cost) *
 					PCT_COST_INSERT_INDEX * 100;
@@ -4884,9 +4873,9 @@ row_merge_build_indexes(
 
 				error = row_merge_insert_index_tuples(
 					sort_idx, old_table,
-					merge_files[i].fd, block, NULL,
+					merge_files[k].fd, block, NULL,
 					&btr_bulk,
-					merge_files[i].n_rec, pct_progress, pct_cost,
+					merge_files[k].n_rec, pct_progress, pct_cost,
 					crypt_block, new_table->space, stage);
 
 				error = btr_bulk.finish(error);
@@ -4904,7 +4893,7 @@ row_merge_build_indexes(
 		}
 
 		/* Close the temporary file to free up space. */
-		row_merge_file_destroy(&merge_files[i]);
+		row_merge_file_destroy(&merge_files[k++]);
 
 		if (indexes[i]->type & DICT_FTS) {
 			row_fts_psort_info_destroy(psort_info, merge_info);
@@ -4916,7 +4905,12 @@ row_merge_build_indexes(
 			ut_ad(sort_idx->online_status
 			      == ONLINE_INDEX_COMPLETE);
 		} else {
-			if (flush_observer) {
+			if (dict_index_is_spatial(indexes[i])) {
+				/* We never disable redo logging for
+				creating SPATIAL INDEX. Avoid writing any
+				unnecessary MLOG_INDEX_LOAD record. */
+			} else if (FlushObserver* flush_observer =
+					trx->get_flush_observer()) {
 				flush_observer->flush();
 				row_merge_write_redo(indexes[i]);
 			}
@@ -4958,7 +4952,7 @@ row_merge_build_indexes(
 
 	row_merge_file_destroy_low(tmpfd);
 
-	for (i = 0; i < n_indexes; i++) {
+	for (i = 0; i < n_merge_files; i++) {
 		row_merge_file_destroy(&merge_files[i]);
 	}
 
@@ -5015,8 +5009,7 @@ row_merge_build_indexes(
 
 	DBUG_EXECUTE_IF("ib_index_crash_after_bulk_load", DBUG_SUICIDE(););
 
-	if (flush_observer != NULL) {
-		ut_ad(need_flush_observer);
+	if (FlushObserver* flush_observer = trx->get_flush_observer()) {
 
 		DBUG_EXECUTE_IF("ib_index_build_fail_before_flush",
 			error = DB_INTERRUPTED;
@@ -5028,7 +5021,7 @@ row_merge_build_indexes(
 
 		flush_observer->flush();
 
-		UT_DELETE(flush_observer);
+		trx->remove_flush_observer();
 
 		if (trx_is_interrupted(trx)) {
 			error = DB_INTERRUPTED;

storage/innobase/trx/trx0trx.cc

 /*****************************************************************************
 
 Copyright (c) 1996, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2015, 2018, MariaDB Corporation.
+Copyright (c) 2015, 2019, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -64,17 +64,6 @@ typedef std::set<
 	std::less<table_id_t>,
 	ut_allocator<table_id_t> >	table_id_set;
 
-/** Set flush observer for the transaction
-@param[in/out]	trx		transaction struct
-@param[in]	observer	flush observer */
-void
-trx_set_flush_observer(
-	trx_t*		trx,
-	FlushObserver*	observer)
-{
-	trx->flush_observer = observer;
-}
-
 /*************************************************************//**
 Set detailed error message for the transaction. */
 void
@@ -165,7 +154,7 @@ trx_init(
 
 	trx->lock.table_cached = 0;
 
-	trx->flush_observer = NULL;
+	ut_ad(trx->get_flush_observer() == NULL);
 }
 
 /** For managing the life-cycle of the trx_t instance that we get
@@ -1088,6 +1077,21 @@ static trx_rseg_t* trx_assign_rseg_low()
 	return(rseg);
 }
 
+/** Set the innodb_log_optimize_ddl page flush observer
+@param[in]	space_id	tablespace id
+@param[in,out]	stage		performance_schema accounting */
+void trx_t::set_flush_observer(ulint space_id, ut_stage_alter_t* stage)
+{
+	flush_observer = UT_NEW_NOKEY(FlushObserver(space_id, this, stage));
+}
+
+/** Remove the flush observer */
+void trx_t::remove_flush_observer()
+{
+	UT_DELETE(flush_observer);
+	flush_observer = NULL;
+}
+
 /** Assign a rollback segment for modifying temporary tables.
 @return the assigned rollback segment */
 trx_rseg_t*