3 files changed, 33 insertions, 144 deletions

diff --git a/storage/innobase/btr/btr0btr.cc b/storage/innobase/btr/btr0btr.cc
index 5338fef551b..674046f0026 100644
--- a/storage/innobase/btr/btr0btr.cc
+++ b/storage/innobase/btr/btr0btr.cc
@@ -725,159 +725,54 @@ btr_page_free_for_ibuf(
 			    mtr));
 }
 
-/**************************************************************//**
-Frees a file page used in an index tree. Can be used also to (BLOB)
-external storage pages. */
-void
-btr_page_free_low(
-/*==============*/
-	dict_index_t*	index,	/*!< in: index tree */
-	buf_block_t*	block,	/*!< in: block to be freed, x-latched */
-	ulint		level,	/*!< in: page level (ULINT_UNDEFINED=BLOB) */
-	bool		blob,   /*!< in: blob page */
-	mtr_t*		mtr)	/*!< in: mtr */
+/** Free an index page.
+@param[in,out]	index	index tree
+@param[in,out]	block	block to be freed
+@param[in,out]	mtr	mini-transaction
+@param[in]	blob	whether this is freeing a BLOB page */
+void btr_page_free(dict_index_t* index, buf_block_t* block, mtr_t* mtr,
+		   bool blob)
 {
-	fseg_header_t*	seg_header;
-	page_t*		root;
-
 	ut_ad(mtr_memo_contains(mtr, block, MTR_MEMO_PAGE_X_FIX));
+#ifdef BTR_CUR_HASH_ADAPT
+	ut_ad(!block->index || !blob);
+	ut_ad(!block->index || page_is_leaf(block->frame));
+#endif
+	ut_ad(index->table->space_id == block->page.id.space());
+	/* The root page is freed by btr_free_root(). */
+	ut_ad(block->page.id.page_no() != index->page);
+	ut_ad(mtr->is_named_space(index->table->space));
+
 	/* The page gets invalid for optimistic searches: increment the frame
 	modify clock */
 
 	buf_block_modify_clock_inc(block);
 
-	if (blob) {
-		ut_a(level == 0);
-	}
-
-	bool scrub = srv_immediate_scrub_data_uncompressed;
-	/* scrub page */
-	if (scrub && blob) {
-		/* blob page: scrub entire page */
-		// TODO(jonaso): scrub only what is actually needed
-		page_t* page = buf_block_get_frame(block);
-		memset(page + PAGE_HEADER, 0,
-		       srv_page_size - PAGE_HEADER);
-#ifdef UNIV_DEBUG_SCRUBBING
-		fprintf(stderr,
-			"btr_page_free_low: scrub blob page %lu/%lu\n",
-			buf_block_get_space(block),
-			buf_block_get_page_no(block));
-#endif /* UNIV_DEBUG_SCRUBBING */
-	} else if (scrub) {
-		/* scrub records on page */
-
-		/* TODO(jonaso): in theory we could clear full page
-		* but, since page still remains in buffer pool, and
-		* gets flushed etc. Lots of routines validates consistency
-		* of it. And in order to remain structurally consistent
-		* we clear each record by it own
-		*
-		* NOTE: The TODO below mentions removing page from buffer pool
-		* and removing redo entries, once that is done, clearing full
-		* pages should be possible
-		*/
-		uint cnt = 0;
-		ulint bytes = 0;
-		page_t* page = buf_block_get_frame(block);
-		mem_heap_t* heap = NULL;
-		ulint* offsets = NULL;
-		rec_t* rec = page_rec_get_next(page_get_infimum_rec(page));
-		while (!page_rec_is_supremum(rec)) {
-			offsets = rec_get_offsets(rec, index, offsets,
-						  page_is_leaf(page),
-						  ULINT_UNDEFINED,
-						  &heap);
-			ulint size = rec_offs_data_size(offsets);
-			memset(rec, 0, size);
-			rec = page_rec_get_next(rec);
-			cnt++;
-			bytes += size;
-		}
-#ifdef UNIV_DEBUG_SCRUBBING
-		fprintf(stderr,
-			"btr_page_free_low: scrub %lu/%lu - "
-			"%u records " ULINTPF " bytes\n",
-			buf_block_get_space(block),
-			buf_block_get_page_no(block),
-			cnt, bytes);
-#endif /* UNIV_DEBUG_SCRUBBING */
-		if (heap) {
-			mem_heap_free(heap);
-		}
-	}
-
-#ifdef UNIV_DEBUG_SCRUBBING
-	if (scrub == false) {
-		fprintf(stderr,
-			"btr_page_free_low %lu/%lu blob: %u\n",
-			buf_block_get_space(block),
-			buf_block_get_page_no(block),
-			blob);
-	}
-#endif /* UNIV_DEBUG_SCRUBBING */
-
 	if (dict_index_is_ibuf(index)) {
-
 		btr_page_free_for_ibuf(index, block, mtr);
-
 		return;
 	}
 
-	root = btr_root_get(index, mtr);
-
-	if (level == 0 || level == ULINT_UNDEFINED) {
-		seg_header = root + PAGE_HEADER + PAGE_BTR_SEG_LEAF;
-	} else {
-		seg_header = root + PAGE_HEADER + PAGE_BTR_SEG_TOP;
-	}
-
-#ifdef UNIV_GIS_DEBUG
-	if (dict_index_is_spatial(index)) {
-		fprintf(stderr, "GIS_DIAG: Freed  %ld\n",
-			(long) block->page.id.page_no());
-	}
-#endif
-
-	if (scrub) {
-		/**
-		* Reset page type so that scrub thread won't try to scrub it
-		*/
-		mlog_write_ulint(buf_block_get_frame(block) + FIL_PAGE_TYPE,
-				 FIL_PAGE_TYPE_ALLOCATED, MLOG_2BYTES, mtr);
-	}
-
+	/* TODO: Discard any operations for block from mtr->log.
+	The page will be freed, so previous changes to it by this
+	mini-transaction should not matter. */
+	page_t* root = btr_root_get(index, mtr);
+	fseg_header_t* seg_header = &root[blob || page_is_leaf(block->frame)
+					  ? PAGE_HEADER + PAGE_BTR_SEG_LEAF
+					  : PAGE_HEADER + PAGE_BTR_SEG_TOP];
 	fseg_free_page(seg_header,
-		       block->page.id.space(),
-		       block->page.id.page_no(),
-		       level != ULINT_UNDEFINED, mtr);
+		       index->table->space, block->page.id.page_no(),
+		       block->index != NULL, mtr);
 
 	/* The page was marked free in the allocation bitmap, but it
-	should remain buffer-fixed until mtr_commit(mtr) or until it
+	should remain exclusively latched until mtr_t::commit() or until it
 	is explicitly freed from the mini-transaction. */
 	ut_ad(mtr_memo_contains(mtr, block, MTR_MEMO_PAGE_X_FIX));
-	/* TODO: Discard any operations on the page from the redo log
-	and remove the block from the flush list and the buffer pool.
-	This would free up buffer pool earlier and reduce writes to
-	both the tablespace and the redo log. */
-}
 
-/**************************************************************//**
-Frees a file page used in an index tree. NOTE: cannot free field external
-storage pages because the page must contain info on its level. */
-void
-btr_page_free(
-/*==========*/
-	dict_index_t*	index,	/*!< in: index tree */
-	buf_block_t*	block,	/*!< in: block to be freed, x-latched */
-	mtr_t*		mtr)	/*!< in: mtr */
-{
-	const page_t*	page	= buf_block_get_frame(block);
-	ulint		level	= btr_page_get_level(page);
-
-	ut_ad(fil_page_index_page_check(block->frame));
-	ut_ad(level != ULINT_UNDEFINED);
-	btr_page_free_low(index, block, level, false, mtr);
+	/* MDEV-15528 FIXME: Zero out the page after the redo log for
+	this mini-transaction has been durably written.
+	This must be done unconditionally if
+	srv_immediate_scrub_data_uncompressed is set. */
 }
 
 /**************************************************************//**
diff --git a/storage/innobase/btr/btr0bulk.cc b/storage/innobase/btr/btr0bulk.cc
index e9b64ebdef3..6a9b71987c5 100644
--- a/storage/innobase/btr/btr0bulk.cc
+++ b/storage/innobase/btr/btr0bulk.cc
@@ -1033,7 +1033,7 @@ BtrBulk::finish(dberr_t	err)
 		root_page_bulk.copyIn(first_rec);
 
 		/* Remove last page. */
-		btr_page_free_low(m_index, last_block, m_root_level, false, &mtr);
+		btr_page_free(m_index, last_block, &mtr);
 
 		/* Do not flush the last page. */
 		last_block->page.flush_observer = NULL;
diff --git a/storage/innobase/btr/btr0cur.cc b/storage/innobase/btr/btr0cur.cc
index 0b61e340f81..1ba0febd415 100644
--- a/storage/innobase/btr/btr0cur.cc
+++ b/storage/innobase/btr/btr0cur.cc
@@ -8145,8 +8145,7 @@ btr_free_externally_stored_field(
 			}
 			next_page_no = mach_read_from_4(page + FIL_PAGE_NEXT);
 
-			btr_page_free_low(index, ext_block, 0,
-				true, &mtr);
+			btr_page_free(index, ext_block, &mtr, true);
 
 			if (page_zip != NULL) {
 				mach_write_to_4(field_ref + BTR_EXTERN_PAGE_NO,
@@ -8172,12 +8171,7 @@ btr_free_externally_stored_field(
 			next_page_no = mach_read_from_4(
 				page + FIL_PAGE_DATA
 				+ BTR_BLOB_HDR_NEXT_PAGE_NO);
-
-			/* We must supply the page level (= 0) as an argument
-			because we did not store it on the page (we save the
-			space overhead from an index page header. */
-			btr_page_free_low(index, ext_block, 0,
-				true, &mtr);
+			btr_page_free(index, ext_block, &mtr, true);
 
 			mlog_write_ulint(field_ref + BTR_EXTERN_PAGE_NO,
 					 next_page_no,