MDEV-12353 preparation: Clean up page_cur_delete_rec()

page_cur_delete_rec(): Do not tolerate mtr=NULL.

page_delete_rec(): Merge with the only caller, RecIterator::remove().

RecIterator::m_mtr: New data member: a dummy mini-transaction.

storage/innobase/include/page0cur.h

@@ -27,12 +27,7 @@ Created 10/4/1994 Heikki Tuuri
 #ifndef page0cur_h
 #define page0cur_h
 
-#include "buf0types.h"
 #include "page0page.h"
-#include "rem0rec.h"
-#include "data0data.h"
-#include "mtr0mtr.h"
-#include "gis0type.h"
 
 #ifdef UNIV_DEBUG
 /*********************************************************//**
@@ -240,7 +235,8 @@ page_cur_delete_rec(
 	const dict_index_t*	index,	/*!< in: record descriptor */
 	const ulint*		offsets,/*!< in: rec_get_offsets(
 					cursor->rec, index) */
-	mtr_t*			mtr);	/*!< in: mini-transaction handle */
+	mtr_t*			mtr)	/*!< in/out: mini-transaction */
+	MY_ATTRIBUTE((nonnull));
 
 /** Search the right position for a page cursor.
 @param[in] block buffer block
@@ -373,20 +369,9 @@ page_cur_parse_delete_rec(
 	const byte*	end_ptr,/*!< in: buffer end */
 	buf_block_t*	block,	/*!< in: page or NULL */
 	dict_index_t*	index,	/*!< in: record descriptor */
-	mtr_t*		mtr);	/*!< in: mtr or NULL */
-/*******************************************************//**
-Removes the record from a leaf page. This function does not log
-any changes. It is used by the IMPORT tablespace functions.
-@return true if success, i.e., the page did not become too empty */
-bool
-page_delete_rec(
-/*============*/
-	const dict_index_t*	index,	/*!< in: The index that the record
-					belongs to */
-	page_cur_t*		pcur,	/*!< in/out: page cursor on record
-					to delete */
-	page_zip_des_t*		page_zip,/*!< in: compressed page descriptor */
-	const ulint*		offsets);/*!< in: offsets for record */
+	mtr_t*		mtr)	/*!< in/out: mini-transaction,
+				or NULL if block=NULL */
+	MY_ATTRIBUTE((warn_unused_result, nonnull(1,2,4)));
 
 /** Index page cursor */
 

storage/innobase/include/page0types.h

 /*****************************************************************************
 
 Copyright (c) 1994, 2016, 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
@@ -163,27 +164,5 @@ page_zip_rec_set_owned(
 	const byte*	rec,	/*!< in: record on the uncompressed page */
 	ulint		flag)	/*!< in: the owned flag (nonzero=TRUE) */
 	MY_ATTRIBUTE((nonnull));
-
-/**********************************************************************//**
-Shift the dense page directory when a record is deleted. */
-void
-page_zip_dir_delete(
-/*================*/
-	page_zip_des_t*	page_zip,/*!< in/out: compressed page */
-	byte*		rec,	/*!< in: deleted record */
-	dict_index_t*	index,	/*!< in: index of rec */
-	const ulint*	offsets,/*!< in: rec_get_offsets(rec) */
-	const byte*	free)	/*!< in: previous start of the free list */
-	MY_ATTRIBUTE((nonnull(1,2,3,4)));
-
-/**********************************************************************//**
-Add a slot to the dense page directory. */
-void
-page_zip_dir_add_slot(
-/*==================*/
-	page_zip_des_t*	page_zip,	/*!< in/out: compressed page */
-	ulint		is_clustered)	/*!< in: nonzero for clustered index,
-					zero for others */
-	MY_ATTRIBUTE((nonnull));
 #endif /* !UNIV_INNOCHECKSUM */
 #endif

storage/innobase/page/page0cur.cc

@@ -2371,11 +2371,14 @@ page_cur_parse_delete_rec(
 	const byte*	end_ptr,/*!< in: buffer end */
 	buf_block_t*	block,	/*!< in: page or NULL */
 	dict_index_t*	index,	/*!< in: record descriptor */
-	mtr_t*		mtr)	/*!< in: mtr or NULL */
+	mtr_t*		mtr)	/*!< in/out: mini-transaction,
+				or NULL if block=NULL */
 {
 	ulint		offset;
 	page_cur_t	cursor;
 
+	ut_ad(!block == !mtr);
+
 	if (end_ptr < ptr + 2) {
 
 		return(NULL);
@@ -2453,13 +2456,10 @@ page_cur_delete_rec(
 	const dict_index_t*	index,	/*!< in: record descriptor */
 	const ulint*		offsets,/*!< in: rec_get_offsets(
 					cursor->rec, index) */
-	mtr_t*			mtr)	/*!< in: mini-transaction handle
-					or NULL */
+	mtr_t*			mtr)	/*!< in/out: mini-transaction */
 {
 	page_dir_slot_t* cur_dir_slot;
 	page_dir_slot_t* prev_slot;
-	page_t*		page;
-	page_zip_des_t*	page_zip;
 	rec_t*		current_rec;
 	rec_t*		prev_rec	= NULL;
 	rec_t*		next_rec;
@@ -2467,36 +2467,36 @@ page_cur_delete_rec(
 	ulint		cur_n_owned;
 	rec_t*		rec;
 
-	page = page_cur_get_page(cursor);
-	page_zip = page_cur_get_page_zip(cursor);
-
 	/* page_zip_validate() will fail here when
 	btr_cur_pessimistic_delete() invokes btr_set_min_rec_mark().
-	Then, both "page_zip" and "page" would have the min-rec-mark
-	set on the smallest user record, but "page" would additionally
+	Then, both "page_zip" and "block->frame" would have the min-rec-mark
+	set on the smallest user record, but "block->frame" would additionally
 	have it set on the smallest-but-one record.  Because sloppy
 	page_zip_validate_low() only ignores min-rec-flag differences
 	in the smallest user record, it cannot be used here either. */
 
 	current_rec = cursor->rec;
+	buf_block_t* const block = cursor->block;
 	ut_ad(rec_offs_validate(current_rec, index, offsets));
-	ut_ad(!!page_is_comp(page) == dict_table_is_comp(index->table));
-	ut_ad(fil_page_index_page_check(page));
-	ut_ad(mach_read_from_8(page + PAGE_HEADER + PAGE_INDEX_ID) == index->id
+	ut_ad(!!page_is_comp(block->frame) == index->table->not_redundant());
+	ut_ad(fil_page_index_page_check(block->frame));
+	ut_ad(mach_read_from_8(PAGE_HEADER + PAGE_INDEX_ID + block->frame)
+	      == index->id
 	      || index->is_dummy
-	      || (mtr ? mtr->is_inside_ibuf() : dict_index_is_ibuf(index)));
-	ut_ad(!mtr || mtr->is_named_space(index->table->space));
+	      || mtr->is_inside_ibuf());
+	ut_ad(mtr->is_named_space(index->table->space));
 
 	/* The record must not be the supremum or infimum record. */
 	ut_ad(page_rec_is_user_rec(current_rec));
 
-	if (page_get_n_recs(page) == 1 && !recv_recovery_is_on()
+	if (page_get_n_recs(block->frame) == 1
+	    && !recv_recovery_is_on()
 	    && !rec_is_alter_metadata(current_rec, *index)) {
 		/* Empty the page, unless we are applying the redo log
 		during crash recovery. During normal operation, the
 		page_create_empty() gets logged as one of MLOG_PAGE_CREATE,
 		MLOG_COMP_PAGE_CREATE, MLOG_ZIP_PAGE_COMPRESS. */
-		ut_ad(page_is_leaf(page));
+		ut_ad(page_is_leaf(block->frame));
 		/* Usually, this should be the root page,
 		and the whole index tree should become empty.
 		However, this could also be a call in
@@ -2512,21 +2512,21 @@ page_cur_delete_rec(
 	/* Save to local variables some data associated with current_rec */
 	cur_slot_no = page_dir_find_owner_slot(current_rec);
 	ut_ad(cur_slot_no > 0);
-	cur_dir_slot = page_dir_get_nth_slot(page, cur_slot_no);
+	cur_dir_slot = page_dir_get_nth_slot(block->frame, cur_slot_no);
 	cur_n_owned = page_dir_slot_get_n_owned(cur_dir_slot);
 
 	/* 1. Reset the last insert info in the page header and increment
 	the modify clock for the frame */
 
-	page_header_set_ptr(page, page_zip, PAGE_LAST_INSERT, NULL);
+	page_zip_des_t* const page_zip = buf_block_get_page_zip(block);
 
-	/* The page gets invalid for optimistic searches: increment the
-	frame modify clock only if there is an mini-transaction covering
-	the change. During IMPORT we allocate local blocks that are not
-	part of the buffer pool. */
+	page_header_set_ptr(block->frame, page_zip, PAGE_LAST_INSERT, NULL);
 
-	if (mtr != 0) {
-		buf_block_modify_clock_inc(page_cur_get_block(cursor));
+	/* The page gets invalid for optimistic searches: increment
+	the frame modify clock. Avoid this during IMPORT; the block is
+	not actually in the buffer pool. */
+	if (mtr->get_log_mode() != MTR_LOG_NONE) {
+		buf_block_modify_clock_inc(block);
 		page_cur_delete_rec_write_log(current_rec, index, mtr);
 	}
 
@@ -2534,9 +2534,9 @@ page_cur_delete_rec(
 	left at the next record. */
 
 	ut_ad(cur_slot_no > 0);
-	prev_slot = page_dir_get_nth_slot(page, cur_slot_no - 1);
+	prev_slot = page_dir_get_nth_slot(block->frame, cur_slot_no - 1);
 
-	rec = (rec_t*) page_dir_slot_get_rec(prev_slot);
+	rec = const_cast<rec_t*>(page_dir_slot_get_rec(prev_slot));
 
 	/* rec now points to the record of the previous directory slot. Look
 	for the immediate predecessor of current_rec in a loop. */
@@ -2570,14 +2570,14 @@ page_cur_delete_rec(
 	page_dir_slot_set_n_owned(cur_dir_slot, page_zip, cur_n_owned - 1);
 
 	/* 6. Free the memory occupied by the record */
-	page_mem_free(page, page_zip, current_rec, index, offsets);
+	page_mem_free(block->frame, page_zip, current_rec, index, offsets);
 
 	/* 7. Now we have decremented the number of owned records of the slot.
 	If the number drops below PAGE_DIR_SLOT_MIN_N_OWNED, we balance the
 	slots. */
 
 	if (cur_n_owned <= PAGE_DIR_SLOT_MIN_N_OWNED) {
-		page_dir_balance_slot(page, page_zip, cur_slot_no);
+		page_dir_balance_slot(block->frame, page_zip, cur_slot_no);
 	}
 }
 

storage/innobase/page/page0page.cc

@@ -2549,62 +2549,6 @@ page_find_rec_with_heap_no(
 	}
 }
 
-/*******************************************************//**
-Removes the record from a leaf page. This function does not log
-any changes. It is used by the IMPORT tablespace functions.
-The cursor is moved to the next record after the deleted one.
-@return true if success, i.e., the page did not become too empty */
-bool
-page_delete_rec(
-/*============*/
-	const dict_index_t*	index,	/*!< in: The index that the record
-					belongs to */
-	page_cur_t*		pcur,	/*!< in/out: page cursor on record
-					to delete */
-	page_zip_des_t*
-#ifdef UNIV_ZIP_DEBUG
-		page_zip/*!< in: compressed page descriptor */
-#endif
-	,
-	const ulint*		offsets)/*!< in: offsets for record */
-{
-	bool		no_compress_needed;
-	buf_block_t*	block = pcur->block;
-	page_t*		page = buf_block_get_frame(block);
-
-	ut_ad(page_is_leaf(page));
-
-	if (!rec_offs_any_extern(offsets)
-	    && (!page_has_siblings(page)
-		|| (page_get_n_recs(page) < 2)
-		|| page_get_data_size(page) - rec_offs_size(offsets)
-		< BTR_CUR_PAGE_COMPRESS_LIMIT(index))) {
-
-		/* The page fillfactor will drop below a predefined
-		minimum value, OR the level in the B-tree contains just
-		one page, OR the page will become empty: we recommend
-		compression if this is not the root page. */
-
-		no_compress_needed = block->page.id.page_no() == index->page;
-	} else {
-		no_compress_needed = true;
-	}
-
-	if (no_compress_needed) {
-#ifdef UNIV_ZIP_DEBUG
-		ut_a(!page_zip || page_zip_validate(page_zip, page, index));
-#endif /* UNIV_ZIP_DEBUG */
-
-		page_cur_delete_rec(pcur, index, offsets, 0);
-
-#ifdef UNIV_ZIP_DEBUG
-		ut_a(!page_zip || page_zip_validate(page_zip, page, index));
-#endif /* UNIV_ZIP_DEBUG */
-	}
-
-	return(no_compress_needed);
-}
-
 /** Get the last non-delete-marked record on a page.
 @param[in]	page	index tree leaf page
 @return the last record, not delete-marked

storage/innobase/row/row0import.cc

@@ -227,6 +227,9 @@ class RecIterator {
 	RecIterator() UNIV_NOTHROW
 	{
 		memset(&m_cur, 0x0, sizeof(m_cur));
+		/* Make page_cur_delete_rec() happy. */
+		m_mtr.start();
+		m_mtr.set_log_mode(MTR_LOG_NONE);
 	}
 
 	/** Position the cursor on the first user record. */
@@ -267,16 +270,40 @@ class RecIterator {
 		page_zip_des_t*		page_zip,
 		ulint*			offsets) UNIV_NOTHROW
 	{
+		ut_ad(page_is_leaf(m_cur.block->frame));
 		/* We can't end up with an empty page unless it is root. */
 		if (page_get_n_recs(m_cur.block->frame) <= 1) {
 			return(false);
 		}
 
-		return(page_delete_rec(index, &m_cur, page_zip, offsets));
+		if (!rec_offs_any_extern(offsets)
+		    && m_cur.block->page.id.page_no() != index->page
+		    && ((page_get_data_size(m_cur.block->frame)
+			 - rec_offs_size(offsets)
+			 < BTR_CUR_PAGE_COMPRESS_LIMIT(index))
+			|| !page_has_siblings(m_cur.block->frame)
+			|| (page_get_n_recs(m_cur.block->frame) < 2))) {
+			return false;
+		}
+
+#ifdef UNIV_ZIP_DEBUG
+		ut_a(!page_zip || page_zip_validate(
+			     page_zip, m_cur.block->frame, index));
+#endif /* UNIV_ZIP_DEBUG */
+
+		page_cur_delete_rec(&m_cur, index, offsets, &m_mtr);
+
+#ifdef UNIV_ZIP_DEBUG
+		ut_a(!page_zip || page_zip_validate(
+			     page_zip, m_cur.block->frame, index));
+#endif /* UNIV_ZIP_DEBUG */
+
+		return true;
 	}
 
 private:
 	page_cur_t	m_cur;
+	mtr_t		m_mtr;
 };
 
 /** Class that purges delete marked reocords from indexes, both secondary