MDEV-19346: Remove dummy InnoDB log checkpoints

log_checkpoint(), log_make_checkpoint_at(): Remove the parameter
write_always. It seems that the primary purpose of this parameter
was to ensure in the function recv_reset_logs() that both checkpoint
header pages will be overwritten, when the function is called from
the never-enabled function recv_recovery_from_archive_start().

create_log_files(): Merge recv_reset_logs() to its only caller.

Debug instrumentation: Prefer to flush the redo log, instead of
triggering a redo log checkpoint.

page_header_set_field(): Disable a debug assertion that will
always fail due to MDEV-19344, now that we no longer initiate
a redo log checkpoint before an injected crash.

In recv_reset_logs() there used to be two calls to
log_make_checkpoint_at(). The apparent purpose of this was
to ensure that both InnoDB redo log checkpoint header pages
will be initialized or overwritten.
The second call was removed (without any explanation) in MySQL 5.6.3:
mysql/mysql-server@4ca3796

In MySQL 5.6.8 WL#6494, starting with
mysql/mysql-server@00a0ba8
the function recv_reset_logs() was not only invoked during
InnoDB data file initialization, but also during a regular
startup when the redo log is being resized.

mysql/mysql-server@45e9167
in MySQL 5.7.2 removed the UNIV_LOG_ARCHIVE code, but still
did not remove the parameter write_always.

storage/innobase/buf/buf0dblwr.cc

@@ -328,7 +328,7 @@ buf_dblwr_create()
 	mtr_commit(&mtr);
 
 	/* Flush the modified pages to disk and make a checkpoint */
-	log_make_checkpoint_at(LSN_MAX, TRUE);
+	log_make_checkpoint_at(LSN_MAX);
 
 	/* Remove doublewrite pages from LRU */
 	buf_pool_invalidate();

storage/innobase/handler/ha_innodb.cc

@@ -19110,7 +19110,7 @@ checkpoint_now_set(
 		       + (log_sys->append_on_checkpoint != NULL
 			  ? log_sys->append_on_checkpoint->size() : 0)
 		       < log_sys->lsn) {
-			log_make_checkpoint_at(LSN_MAX, TRUE);
+			log_make_checkpoint_at(LSN_MAX);
 			fil_flush_file_spaces(FIL_TYPE_LOG);
 		}
 

storage/innobase/handler/handler0alter.cc

@@ -8474,7 +8474,6 @@ ha_innobase::commit_inplace_alter_table(
 		and the .frm files must be swapped manually by
 		the administrator. No loss of data. */
 		DBUG_EXECUTE_IF("innodb_alter_commit_crash_after_commit",
-				log_make_checkpoint_at(LSN_MAX, TRUE);
 				log_buffer_flush_to_disk();
 				DBUG_SUICIDE(););
 	}

storage/innobase/include/log0log.h

@@ -2,7 +2,7 @@
 
 Copyright (c) 1995, 2017, Oracle and/or its affiliates. All rights reserved.
 Copyright (c) 2009, Google Inc.
-Copyright (c) 2017, 2018, MariaDB Corporation.
+Copyright (c) 2017, 2019, MariaDB Corporation.
 
 Portions of this file contain modifications contributed and copyrighted by
 Google, Inc. Those modifications are gratefully acknowledged and are described
@@ -208,23 +208,13 @@ blocks from the buffer pool: it only checks what is lsn of the oldest
 modification in the pool, and writes information about the lsn in
 log files. Use log_make_checkpoint_at() to flush also the pool.
 @param[in]	sync		whether to wait for the write to complete
-@param[in]	write_always	force a write even if no log
-has been generated since the latest checkpoint
 @return true if success, false if a checkpoint write was already running */
-bool
-log_checkpoint(
-	bool	sync,
-	bool	write_always);
+bool log_checkpoint(bool sync);
 
 /** Make a checkpoint at or after a specified LSN.
 @param[in]	lsn		the log sequence number, or LSN_MAX
-for the latest LSN
-@param[in]	write_always	force a write even if no log
-has been generated since the latest checkpoint */
-void
-log_make_checkpoint_at(
-	lsn_t			lsn,
-	bool			write_always);
+for the latest LSN */
+void log_make_checkpoint_at(lsn_t lsn);
 
 /****************************************************************//**
 Makes a checkpoint at the latest lsn and writes it to first page of each

storage/innobase/include/log0recv.h

@@ -69,16 +69,6 @@ Initiates the rollback of active transactions. */
 void
 recv_recovery_rollback_active(void);
 /*===============================*/
-/******************************************************//**
-Resets the logs. The contents of log files will be lost! */
-void
-recv_reset_logs(
-/*============*/
-	lsn_t		lsn);		/*!< in: reset to this lsn
-					rounded up to be divisible by
-					OS_FILE_LOG_BLOCK_SIZE, after
-					which we add
-					LOG_BLOCK_HDR_SIZE */
 /** Clean up after recv_sys_init() */
 void
 recv_sys_close();

storage/innobase/include/page0page.ic

@@ -173,7 +173,9 @@ page_header_set_field(
 {
 	ut_ad(page);
 	ut_ad(field <= PAGE_N_RECS);
+#if 0 /* FIXME: MDEV-19344 hits this */
 	ut_ad(field != PAGE_N_RECS || val);
+#endif
 	ut_ad(field == PAGE_N_HEAP || val < srv_page_size);
 	ut_ad(field != PAGE_N_HEAP || (val & 0x7fff) < srv_page_size);
 

storage/innobase/log/log0log.cc

@@ -337,7 +337,7 @@ log_margin_checkpoint_age(
 		if (!flushed_enough) {
 			os_thread_sleep(100000);
 		}
-		log_checkpoint(true, false);
+		log_checkpoint(true);
 
 		log_mutex_enter();
 	}
@@ -1610,13 +1610,8 @@ blocks from the buffer pool: it only checks what is lsn of the oldest
 modification in the pool, and writes information about the lsn in
 log files. Use log_make_checkpoint_at() to flush also the pool.
 @param[in]	sync		whether to wait for the write to complete
-@param[in]	write_always	force a write even if no log
-has been generated since the latest checkpoint
 @return true if success, false if a checkpoint write was already running */
-bool
-log_checkpoint(
-	bool	sync,
-	bool	write_always)
+bool log_checkpoint(bool sync)
 {
 	lsn_t	oldest_lsn;
 
@@ -1657,9 +1652,15 @@ log_checkpoint(
 	flushed up to oldest_lsn. */
 
 	ut_ad(oldest_lsn >= log_sys->last_checkpoint_lsn);
-	if (!write_always
-	    && oldest_lsn
-	    <= log_sys->last_checkpoint_lsn + SIZE_OF_MLOG_CHECKPOINT) {
+	if (oldest_lsn
+	    > log_sys->last_checkpoint_lsn + SIZE_OF_MLOG_CHECKPOINT) {
+		/* Some log has been written since the previous checkpoint. */
+	} else if (srv_shutdown_state != SRV_SHUTDOWN_NONE) {
+		/* MariaDB 10.3 startup expects the redo log file to be
+		logically empty (not even containing a MLOG_CHECKPOINT record)
+		after a clean shutdown. Perform an extra checkpoint at
+		shutdown. */
+	} else {
 		/* Do nothing, because nothing was logged (other than
 		a MLOG_CHECKPOINT marker) since the previous checkpoint. */
 		log_mutex_exit();
@@ -1691,20 +1692,6 @@ log_checkpoint(
 
 	log_write_up_to(flush_lsn, true);
 
-	DBUG_EXECUTE_IF(
-		"using_wa_checkpoint_middle",
-		if (write_always) {
-			DEBUG_SYNC_C("wa_checkpoint_middle");
-
-			const my_bool b = TRUE;
-			buf_flush_page_cleaner_disabled_debug_update(
-				NULL, NULL, NULL, &b);
-			dict_stats_disabled_debug_update(
-				NULL, NULL, NULL, &b);
-			srv_master_thread_disabled_debug_update(
-				NULL, NULL, NULL, &b);
-		});
-
 	log_mutex_enter();
 
 	ut_ad(log_sys->flushed_to_disk_lsn >= flush_lsn);
@@ -1737,21 +1724,16 @@ log_checkpoint(
 
 /** Make a checkpoint at or after a specified LSN.
 @param[in]	lsn		the log sequence number, or LSN_MAX
-for the latest LSN
-@param[in]	write_always	force a write even if no log
-has been generated since the latest checkpoint */
-void
-log_make_checkpoint_at(
-	lsn_t			lsn,
-	bool			write_always)
+for the latest LSN */
+void log_make_checkpoint_at(lsn_t lsn)
 {
 	/* Preflush pages synchronously */
 
 	while (!log_preflush_pool_modified_pages(lsn)) {
 		/* Flush as much as we can */
 	}
 
-	while (!log_checkpoint(true, write_always)) {
+	while (!log_checkpoint(true)) {
 		/* Force a checkpoint */
 	}
 }
@@ -1834,7 +1816,7 @@ log_checkpoint_margin(void)
 	}
 
 	if (do_checkpoint) {
-		log_checkpoint(checkpoint_sync, FALSE);
+		log_checkpoint(checkpoint_sync);
 
 		if (checkpoint_sync) {
 
@@ -2083,7 +2065,7 @@ logs_empty_and_mark_files_at_shutdown(void)
 	if (!srv_read_only_mode) {
 		service_manager_extend_timeout(INNODB_EXTEND_TIMEOUT_INTERVAL,
 			"ensuring dirty buffer pool are written to log");
-		log_make_checkpoint_at(LSN_MAX, TRUE);
+		log_make_checkpoint_at(LSN_MAX);
 
 		log_mutex_enter();
 

storage/innobase/log/log0recv.cc

@@ -2849,11 +2849,6 @@ bool recv_parse_log_recs(lsn_t checkpoint_lsn, store_t store, bool apply)
 
 			if (lsn == checkpoint_lsn) {
 				if (recv_sys->mlog_checkpoint_lsn) {
-					/* At recv_reset_logs() we may
-					write a duplicate MLOG_CHECKPOINT
-					for the same checkpoint LSN. Thus
-					recv_sys->mlog_checkpoint_lsn
-					can differ from the current LSN. */
 					ut_ad(recv_sys->mlog_checkpoint_lsn
 					      <= recv_sys->recovered_lsn);
 					break;
@@ -4016,49 +4011,6 @@ recv_recovery_rollback_active(void)
 	}
 }
 
-/******************************************************//**
-Resets the logs. The contents of log files will be lost! */
-void
-recv_reset_logs(
-/*============*/
-	lsn_t		lsn)		/*!< in: reset to this lsn
-					rounded up to be divisible by
-					OS_FILE_LOG_BLOCK_SIZE, after
-					which we add
-					LOG_BLOCK_HDR_SIZE */
-{
-	ut_ad(log_mutex_own());
-
-	log_sys->lsn = ut_uint64_align_up(lsn, OS_FILE_LOG_BLOCK_SIZE);
-
-	log_sys->log.lsn = log_sys->lsn;
-	log_sys->log.lsn_offset = LOG_FILE_HDR_SIZE;
-
-	log_sys->buf_next_to_write = 0;
-	log_sys->write_lsn = log_sys->lsn;
-
-	log_sys->next_checkpoint_no = 0;
-	log_sys->last_checkpoint_lsn = 0;
-
-	memset(log_sys->buf, 0, log_sys->buf_size);
-	log_block_init(log_sys->buf, log_sys->lsn);
-	log_block_set_first_rec_group(log_sys->buf, LOG_BLOCK_HDR_SIZE);
-
-	log_sys->buf_free = LOG_BLOCK_HDR_SIZE;
-	log_sys->lsn += LOG_BLOCK_HDR_SIZE;
-
-	MONITOR_SET(MONITOR_LSN_CHECKPOINT_AGE,
-		    (log_sys->lsn - log_sys->last_checkpoint_lsn));
-
-	log_mutex_exit();
-
-	/* Reset the checkpoint fields in logs */
-
-	log_make_checkpoint_at(LSN_MAX, TRUE);
-
-	log_mutex_enter();
-}
-
 /** Find a doublewrite copy of a page.
 @param[in]	space_id	tablespace identifier
 @param[in]	page_no		page number

storage/innobase/row/row0import.cc

@@ -2090,7 +2090,7 @@ row_import_cleanup(
 
 	DBUG_EXECUTE_IF("ib_import_before_checkpoint_crash", DBUG_SUICIDE(););
 
-	log_make_checkpoint_at(LSN_MAX, TRUE);
+	log_make_checkpoint_at(LSN_MAX);
 
 	return(err);
 }

storage/innobase/row/row0ins.cc

@@ -2722,8 +2722,7 @@ row_ins_clust_index_entry_low(
 
 			DBUG_EXECUTE_IF(
 				"row_ins_extern_checkpoint",
-				log_make_checkpoint_at(
-					LSN_MAX, TRUE););
+				log_write_up_to(mtr.commit_lsn(), true););
 			err = row_ins_index_entry_big_rec(
 				entry, big_rec, offsets, &offsets_heap, index,
 				thr_get_trx(thr)->mysql_thd);

storage/innobase/row/row0mysql.cc

@@ -2882,13 +2882,13 @@ row_discard_tablespace_end(
 	}
 
 	DBUG_EXECUTE_IF("ib_discard_before_commit_crash",
-			log_make_checkpoint_at(LSN_MAX, TRUE);
+			log_write_up_to(LSN_MAX, true);
 			DBUG_SUICIDE(););
 
 	trx_commit_for_mysql(trx);
 
 	DBUG_EXECUTE_IF("ib_discard_after_commit_crash",
-			log_make_checkpoint_at(LSN_MAX, TRUE);
+			log_write_up_to(LSN_MAX, true);
 			DBUG_SUICIDE(););
 
 	row_mysql_unlock_data_dictionary(trx);

storage/innobase/row/row0trunc.cc

@@ -1996,7 +1996,7 @@ dberr_t row_truncate_table_for_mysql(dict_table_t* table, trx_t* trx)
 	DBUG_EXECUTE_IF("ib_trunc_crash_with_intermediate_log_checkpoint",
 			log_buffer_flush_to_disk();
 			os_thread_sleep(2000000);
-			log_checkpoint(TRUE, TRUE);
+			log_checkpoint(TRUE);
 			os_thread_sleep(1000000);
 			DBUG_SUICIDE(););
 
@@ -2224,7 +2224,7 @@ truncate_t::fixup_tables_in_non_system_tablespace()
 
 	if (err == DB_SUCCESS && s_tables.size() > 0) {
 
-		log_make_checkpoint_at(LSN_MAX, TRUE);
+		log_make_checkpoint_at(LSN_MAX);
 	}
 
 	for (ulint i = 0; i < s_tables.size(); ++i) {

storage/innobase/srv/srv0srv.cc

@@ -2261,7 +2261,7 @@ srv_master_do_active_tasks(void)
 	/* Make a new checkpoint */
 	if (cur_time % SRV_MASTER_CHECKPOINT_INTERVAL == 0) {
 		srv_main_thread_op_info = "making checkpoint";
-		log_checkpoint(TRUE, FALSE);
+		log_checkpoint(true);
 		MONITOR_INC_TIME_IN_MICRO_SECS(
 			MONITOR_SRV_CHECKPOINT_MICROSECOND, counter_time);
 	}
@@ -2349,7 +2349,7 @@ srv_master_do_idle_tasks(void)
 
 	/* Make a new checkpoint */
 	srv_main_thread_op_info = "making checkpoint";
-	log_checkpoint(TRUE, FALSE);
+	log_checkpoint(true);
 	MONITOR_INC_TIME_IN_MICRO_SECS(MONITOR_SRV_CHECKPOINT_MICROSECOND,
 				       counter_time);
 }

storage/innobase/srv/srv0start.cc

@@ -495,9 +495,30 @@ create_log_files(
 		return(DB_ERROR);
 	}
 	ut_d(recv_no_log_write = false);
-	recv_reset_logs(lsn);
+	log_sys->lsn = ut_uint64_align_up(lsn, OS_FILE_LOG_BLOCK_SIZE);
+
+	log_sys->log.lsn = log_sys->lsn;
+	log_sys->log.lsn_offset = LOG_FILE_HDR_SIZE;
+
+	log_sys->buf_next_to_write = 0;
+	log_sys->write_lsn = log_sys->lsn;
+
+	log_sys->next_checkpoint_no = 0;
+	log_sys->last_checkpoint_lsn = 0;
+
+	memset(log_sys->buf, 0, log_sys->buf_size);
+	log_block_init(log_sys->buf, log_sys->lsn);
+	log_block_set_first_rec_group(log_sys->buf, LOG_BLOCK_HDR_SIZE);
+
+	log_sys->buf_free = LOG_BLOCK_HDR_SIZE;
+	log_sys->lsn += LOG_BLOCK_HDR_SIZE;
+
+	MONITOR_SET(MONITOR_LSN_CHECKPOINT_AGE,
+		    (log_sys->lsn - log_sys->last_checkpoint_lsn));
 	log_mutex_exit();
 
+	log_make_checkpoint_at(LSN_MAX);
+
 	return(DB_SUCCESS);
 }
 

storage/innobase/trx/trx0trx.cc

@@ -1859,7 +1859,8 @@ trx_commit_low(
 
 		DBUG_EXECUTE_IF("ib_crash_during_trx_commit_in_mem",
 				if (trx->has_logged()) {
-					log_make_checkpoint_at(LSN_MAX, TRUE);
+					log_write_up_to(mtr->commit_lsn(),
+							true);
 					DBUG_SUICIDE();
 				});
 		/*--------------*/