MDEV-19506 Remove the global sequence DICT_HDR_ROW_ID for DB_ROW_ID

InnoDB tables that lack a primary key (and any UNIQUE INDEX whose
all columns are NOT NULL) will use an internally generated index,
called GEN_CLUST_INDEX(DB_ROW_ID) in the InnoDB data dictionary,
and hidden from the SQL layer.

The 48-bit (6-byte) DB_ROW_ID is being assigned from a
global sequence that is persisted in the DICT_HDR page.

There is absolutely no reason for the DB_ROW_ID to be globally
unique across all InnoDB tables.

A downgrade to earlier versions will be prevented by the file format
change related to removing the InnoDB change buffer (MDEV-29694).

DICT_HDR_ROW_ID, dict_sys_t::row_id: Remove.

dict_table_t::row_id: The per-table sequence of DB_ROW_ID.

commit_try_rebuild(): Copy dict_table_t::row_id from the old table.

btr_cur_instant_init(), row_import_cleanup(): If needed, perform
the equivalent of SELECT MAX(DB_ROW_ID) to initialize
dict_table_t::row_id.

row_ins(): If needed, obtain DB_ROW_ID from dict_table_t::row_id.
Should it exceed the maximum 48-bit value, return DB_OUT_OF_FILE_SPACE
to prevent further inserts into the table.

dict_load_table_one(): Move a condition to btr_cur_instant_init_low()
so that dict_table_t::row_id will be restored also for
ROW_FORMAT=COMPRESSED tables.

Tested by: Matthias Leich

storage/innobase/btr/btr0cur.cc

@@ -348,10 +348,14 @@ when loading a table definition.
 static dberr_t btr_cur_instant_init_low(dict_index_t* index, mtr_t* mtr)
 {
 	ut_ad(index->is_primary());
-	ut_ad(index->n_core_null_bytes == dict_index_t::NO_CORE_NULL_BYTES);
-	ut_ad(index->table->supports_instant());
 	ut_ad(index->table->is_readable());
 
+	if (!index->table->supports_instant()) {
+		return DB_SUCCESS;
+	}
+
+	ut_ad(index->n_core_null_bytes == dict_index_t::NO_CORE_NULL_BYTES);
+
 	dberr_t err;
 	const fil_space_t* space = index->table->space;
 	if (!space) {
@@ -618,17 +622,25 @@ when loading a table definition.
 @param[in,out]	table	table definition from the data dictionary
 @return	error code
 @retval	DB_SUCCESS	if no error occurred */
-dberr_t
-btr_cur_instant_init(dict_table_t* table)
+dberr_t btr_cur_instant_init(dict_table_t *table)
 {
-	mtr_t		mtr;
-	dict_index_t*	index = dict_table_get_first_index(table);
-	mtr.start();
-	dberr_t	err = index
-		? btr_cur_instant_init_low(index, &mtr)
-		: DB_CORRUPTION;
-	mtr.commit();
-	return(err);
+  mtr_t mtr;
+  dict_index_t *index= dict_table_get_first_index(table);
+  mtr.start();
+  dberr_t err = index ? btr_cur_instant_init_low(index, &mtr) : DB_CORRUPTION;
+  mtr.commit();
+  if (err == DB_SUCCESS && index->is_gen_clust())
+  {
+    btr_cur_t cur;
+    mtr.start();
+    err= cur.open_leaf(false, index, BTR_SEARCH_LEAF, &mtr);
+    if (err != DB_SUCCESS);
+    else if (const rec_t *rec= page_rec_get_prev(btr_cur_get_rec(&cur)))
+      if (page_rec_is_user_rec(rec))
+        table->row_id= mach_read_from_6(rec);
+    mtr.commit();
+  }
+  return(err);
 }
 
 /** Initialize the n_core_null_bytes on first access to a clustered

storage/innobase/dict/dict0boot.cc

@@ -93,18 +93,6 @@ dict_hdr_get_new_id(
 	mtr.commit();
 }
 
-/** Update dict_sys.row_id in the dictionary header file page. */
-void dict_hdr_flush_row_id(row_id_t id)
-{
-  mtr_t mtr;
-  mtr.start();
-  buf_block_t* d= dict_hdr_get(&mtr);
-  byte *row_id= DICT_HDR + DICT_HDR_ROW_ID + d->page.frame;
-  if (mach_read_from_8(row_id) < id)
-    mtr.write<8>(*d, row_id, id);
-  mtr.commit();
-}
-
 /** Create the DICT_HDR page on database initialization.
 @return error code */
 dberr_t dict_create()
@@ -126,10 +114,8 @@ dberr_t dict_create()
 	}
 	ut_a(d->page.id() == hdr_page_id);
 
-	/* Start counting row, table, index, and tree ids from
+	/* Start counting table, index, and tree ids from
 	DICT_HDR_FIRST_ID */
-	mtr.write<8>(*d, DICT_HDR + DICT_HDR_ROW_ID + d->page.frame,
-		     DICT_HDR_FIRST_ID);
 	mtr.write<8>(*d, DICT_HDR + DICT_HDR_TABLE_ID + d->page.frame,
 		     DICT_HDR_FIRST_ID);
 	mtr.write<8>(*d, DICT_HDR + DICT_HDR_INDEX_ID + d->page.frame,
@@ -245,17 +231,6 @@ dberr_t dict_boot()
 
 	const byte* dict_hdr = &d->page.frame[DICT_HDR];
 
-	/* Because we only write new row ids to disk-based data structure
-	(dictionary header) when it is divisible by
-	DICT_HDR_ROW_ID_WRITE_MARGIN, in recovery we will not recover
-	the latest value of the row id counter. Therefore we advance
-	the counter at the database startup to avoid overlapping values.
-	Note that when a user after database startup first time asks for
-	a new row id, then because the counter is now divisible by
-	..._MARGIN, it will immediately be updated to the disk-based
-	header. */
-
-	dict_sys.recover_row_id(mach_read_from_8(dict_hdr + DICT_HDR_ROW_ID));
 	if (uint32_t max_space_id
 	    = mach_read_from_4(dict_hdr + DICT_HDR_MAX_SPACE_ID)) {
 		max_space_id--;

storage/innobase/dict/dict0dict.cc

@@ -1180,6 +1180,7 @@ inline void dict_sys_t::add(dict_table_t* table)
 	ulint fold = my_crc32c(0, table->name.m_name,
 			       strlen(table->name.m_name));
 
+	table->row_id = 0;
 	table->autoinc_mutex.init();
 	table->lock_mutex_init();
 

storage/innobase/dict/dict0load.cc

@@ -2471,9 +2471,7 @@ static dict_table_t *dict_load_table_one(const span<const char> &name,
 				goto corrupted;
 			}
 
-			if (table->supports_instant()) {
-				err = btr_cur_instant_init(table);
-			}
+			err = btr_cur_instant_init(table);
 		}
 	} else {
 		ut_ad(ignore_err & DICT_ERR_IGNORE_INDEX);

storage/innobase/handler/handler0alter.cc

@@ -10219,6 +10219,7 @@ commit_try_rebuild(
 
 	/* We must be still holding a table handle. */
 	DBUG_ASSERT(user_table->get_ref_count() == 1);
+	rebuilt_table->row_id = uint64_t{user_table->row_id};
 	DBUG_EXECUTE_IF("ib_rebuild_cannot_rename", error = DB_ERROR;);
 
 	switch (error) {

storage/innobase/include/dict0boot.h

@@ -44,39 +44,6 @@ dict_hdr_get_new_id(
 						(not assigned if NULL) */
 	uint32_t*		space_id);	/*!< out: space id
 						(not assigned if NULL) */
-/** Update dict_sys.row_id in the dictionary header file page. */
-void dict_hdr_flush_row_id(row_id_t id);
-/** @return A new value for GEN_CLUST_INDEX(DB_ROW_ID) */
-inline row_id_t dict_sys_t::get_new_row_id()
-{
-  row_id_t id= row_id.fetch_add(1);
-  if (!(id % ROW_ID_WRITE_MARGIN))
-    dict_hdr_flush_row_id(id);
-  return id;
-}
-
-/** Ensure that row_id is not smaller than id, on IMPORT TABLESPACE */
-inline void dict_sys_t::update_row_id(row_id_t id)
-{
-  row_id_t sys_id= row_id;
-  while (id >= sys_id)
-  {
-    if (!row_id.compare_exchange_strong(sys_id, id))
-      continue;
-    if (!(id % ROW_ID_WRITE_MARGIN))
-      dict_hdr_flush_row_id(id);
-    break;
-  }
-}
-
-/**********************************************************************//**
-Writes a row id to a record or other 6-byte stored form. */
-inline void dict_sys_write_row_id(byte *field, row_id_t row_id)
-{
-  static_assert(DATA_ROW_ID_LEN == 6, "compatibility");
-  mach_write_to_6(field, row_id);
-}
-
 /*****************************************************************//**
 Initializes the data dictionary memory structures when the database is
 started. This function is also called when the data dictionary is created.
@@ -116,7 +83,7 @@ inline bool dict_is_sys_table(table_id_t id) { return id < DICT_HDR_FIRST_ID; }
 
 /*-------------------------------------------------------------*/
 /* Dictionary header offsets */
-#define DICT_HDR_ROW_ID		0	/* The latest assigned row id */
+//#define DICT_HDR_ROW_ID	0	/* Was: latest assigned DB_ROW_ID */
 #define DICT_HDR_TABLE_ID	8	/* The latest assigned table id */
 #define DICT_HDR_INDEX_ID	16	/* The latest assigned index id */
 #define DICT_HDR_MAX_SPACE_ID	24	/* The latest assigned space id,or 0*/

storage/innobase/include/dict0dict.h

@@ -648,7 +648,7 @@ dict_table_get_all_fts_indexes(
 /********************************************************************//**
 Gets the number of user-defined non-virtual columns in a table in the
 dictionary cache.
-@return number of user-defined (e.g., not ROW_ID) non-virtual
+@return number of user-defined (e.g., not DB_ROW_ID) non-virtual
 columns of a table */
 UNIV_INLINE
 unsigned
@@ -1370,27 +1370,10 @@ class dict_sys_t
   std::atomic<table_id_t> temp_table_id{DICT_HDR_FIRST_ID};
   /** hash table of temporary table IDs */
   hash_table_t temp_id_hash;
-  /** the next value of DB_ROW_ID, backed by DICT_HDR_ROW_ID
-  (FIXME: remove this, and move to dict_table_t) */
-  Atomic_relaxed<row_id_t> row_id;
-  /** The synchronization interval of row_id */
-  static constexpr size_t ROW_ID_WRITE_MARGIN= 256;
 public:
   /** Diagnostic message for exceeding the lock_wait() timeout */
   static const char fatal_msg[];
 
-  /** @return A new value for GEN_CLUST_INDEX(DB_ROW_ID) */
-  inline row_id_t get_new_row_id();
-
-  /** Ensure that row_id is not smaller than id, on IMPORT TABLESPACE */
-  inline void update_row_id(row_id_t id);
-
-  /** Recover the global DB_ROW_ID sequence on database startup */
-  void recover_row_id(row_id_t id)
-  {
-    row_id= ut_uint64_align_up(id, ROW_ID_WRITE_MARGIN) + ROW_ID_WRITE_MARGIN;
-  }
-
   /** @return a new temporary table ID */
   table_id_t acquire_temporary_table_id()
   {

storage/innobase/include/dict0dict.inl

@@ -244,7 +244,7 @@ dict_table_get_next_index(
 /********************************************************************//**
 Gets the number of user-defined non-virtual columns in a table in the
 dictionary cache.
-@return number of user-defined (e.g., not ROW_ID) non-virtual
+@return number of user-defined (e.g., not DB_ROW_ID) non-virtual
 columns of a table */
 UNIV_INLINE
 unsigned

storage/innobase/include/dict0mem.h

@@ -2347,6 +2347,8 @@ struct dict_table_t {
   Atomic_relaxed<pthread_t> lock_mutex_owner{0};
 #endif
 public:
+  /** The next DB_ROW_ID value */
+  Atomic_counter<uint64_t> row_id{0};
   /** Autoinc counter value to give to the next inserted row. */
   uint64_t autoinc;
 

storage/innobase/row/row0import.cc

@@ -2109,8 +2109,9 @@ row_import_cleanup(
 	row_prebuilt_t*	prebuilt,	/*!< in/out: prebuilt from handler */
 	dberr_t		err)		/*!< in: error code */
 {
+	dict_table_t* table = prebuilt->table;
+
 	if (err != DB_SUCCESS) {
-		dict_table_t* table = prebuilt->table;
 		table->file_unreadable = true;
 		if (table->space) {
 			fil_close_tablespace(table->space_id);
@@ -2141,7 +2142,25 @@ row_import_cleanup(
 
 	DBUG_EXECUTE_IF("ib_import_before_checkpoint_crash", DBUG_SUICIDE(););
 
-	return(err);
+	if (err != DB_SUCCESS
+	    || !dict_table_get_first_index(table)->is_gen_clust()) {
+		return err;
+	}
+
+	btr_cur_t cur;
+	mtr_t mtr;
+	mtr.start();
+	err = cur.open_leaf(false, dict_table_get_first_index(table),
+			    BTR_SEARCH_LEAF, &mtr);
+	if (err != DB_SUCCESS) {
+	} else if (const rec_t *rec =
+		   page_rec_get_prev(btr_cur_get_rec(&cur))) {
+		if (page_rec_is_user_rec(rec))
+			table->row_id= mach_read_from_6(rec);
+	}
+	mtr.commit();
+
+	return err;
 }
 
 /*****************************************************************//**
@@ -2276,55 +2295,6 @@ row_import_adjust_root_pages_of_secondary_indexes(
 	return(err);
 }
 
-/*****************************************************************//**
-Ensure that dict_sys.row_id exceeds SELECT MAX(DB_ROW_ID). */
-MY_ATTRIBUTE((nonnull)) static
-void
-row_import_set_sys_max_row_id(
-/*==========================*/
-	row_prebuilt_t*		prebuilt,	/*!< in/out: prebuilt from
-						handler */
-	const dict_table_t*	table)		/*!< in: table to import */
-{
-	const rec_t*		rec;
-	mtr_t			mtr;
-	btr_pcur_t		pcur;
-	row_id_t		row_id	= 0;
-	dict_index_t*		index;
-
-	index = dict_table_get_first_index(table);
-	ut_ad(index->is_primary());
-	ut_ad(dict_index_is_auto_gen_clust(index));
-
-	mtr_start(&mtr);
-
-	mtr_set_log_mode(&mtr, MTR_LOG_NO_REDO);
-
-	if (pcur.open_leaf(false, index, BTR_SEARCH_LEAF, &mtr)
-	    == DB_SUCCESS) {
-		rec = btr_pcur_move_to_prev_on_page(&pcur);
-
-		if (!rec) {
-			/* The table is corrupted. */
-		} else if (page_rec_is_infimum(rec)) {
-			/* The table is empty. */
-		} else if (rec_is_metadata(rec, *index)) {
-			/* The clustered index contains the metadata
-			record only, that is, the table is empty. */
-		} else {
-			row_id = mach_read_from_6(rec);
-		}
-	}
-
-	mtr_commit(&mtr);
-
-	if (row_id) {
-		/* Update the system row id if the imported index row id is
-		greater than the max system row id. */
-		dict_sys.update_row_id(row_id);
-	}
-}
-
 /*****************************************************************//**
 Read the a string from the meta data file.
 @return DB_SUCCESS or error code. */
@@ -4510,13 +4480,6 @@ row_import_for_mysql(
 		return row_import_error(prebuilt, err);
 	}
 
-	/* Ensure that the next available DB_ROW_ID is not smaller than
-	any DB_ROW_ID stored in the table. */
-
-	if (prebuilt->clust_index_was_generated) {
-		row_import_set_sys_max_row_id(prebuilt, table);
-	}
-
 	ib::info() << "Phase III - Flush changes to disk";
 
 	/* Ensure that all pages dirtied during the IMPORT make it to disk.

storage/innobase/row/row0ins.cc

@@ -3525,19 +3525,6 @@ row_ins_index_entry_step(
 	DBUG_RETURN(err);
 }
 
-/***********************************************************//**
-Allocates a row id for row and inits the node->index field. */
-UNIV_INLINE
-void
-row_ins_alloc_row_id_step(
-/*======================*/
-	ins_node_t*	node)	/*!< in: row insert node */
-{
-  ut_ad(node->state == INS_NODE_ALLOC_ROW_ID);
-  if (dict_table_get_first_index(node->table)->is_gen_clust())
-    dict_sys_write_row_id(node->sys_buf, dict_sys.get_new_row_id());
-}
-
 /***********************************************************//**
 Gets a row to insert from the values list. */
 UNIV_INLINE
@@ -3618,13 +3605,18 @@ row_ins(
 	DBUG_PRINT("row_ins", ("table: %s", node->table->name.m_name));
 
 	if (node->state == INS_NODE_ALLOC_ROW_ID) {
-
-		row_ins_alloc_row_id_step(node);
-
 		node->index = dict_table_get_first_index(node->table);
 		ut_ad(node->entry_list.empty() == false);
 		node->entry = node->entry_list.begin();
 
+		if (node->index->is_gen_clust()) {
+			const uint64_t db_row_id{++node->table->row_id};
+			if (db_row_id >> 48) {
+				DBUG_RETURN(DB_OUT_OF_FILE_SPACE);
+			}
+			mach_write_to_6(node->sys_buf, db_row_id);
+		}
+
 		if (node->ins_type == INS_SEARCHED) {
 
 			row_ins_get_row_from_select(node);