InnoDB: Remove redundant page_no field from dict_index_t.

This completes the patch for fast TRUNCATE TABLE.


innobase/dict/dict0boot.c:
  dict_boot(): Add page_no parameter to dict_index_add_to_cache()
innobase/dict/dict0crea.c:
  Remove dict_index_t:page_no; add ind_node_t:page_no
innobase/dict/dict0dict.c:
  dict_index_add_to_cache(): Add parameter page_no
  dict_tree_create(): Add parameter page_no
innobase/dict/dict0load.c:
  dict_load_indexes(): Add page_no to dict_index_add_to_cache() call
innobase/ibuf/ibuf0ibuf.c:
  ibuf_data_init_for_space(): Move page_no to dict_index_add_to_cache()
innobase/include/dict0crea.h:
  ind_node_t: Add page_no field
innobase/include/dict0dict.h:
  dict_index_add_to_cache(): Add page_no
  dict_tree_create(): Add page_no
innobase/include/dict0mem.h:
  dict_index_t: Remove page_no, as dict_tree_t has "page" field
innobase/row/row0mysql.c:
  row_truncate_table_for_mysql(): Improve the comments

innobase/dict/dict0boot.c

@@ -223,6 +223,7 @@ dict_boot(void)
 	dict_index_t*	index;
 	dict_hdr_t*	dict_hdr;
 	mtr_t		mtr;
+	ibool		success;
 
 	mtr_start(&mtr);
 	
@@ -275,20 +276,20 @@ dict_boot(void)
 
 	dict_mem_index_add_field(index, "NAME", 0, 0);
 
-	index->page_no = mtr_read_ulint(dict_hdr + DICT_HDR_TABLES,
-							MLOG_4BYTES, &mtr);
 	index->id = DICT_TABLES_ID;
 
-	ut_a(dict_index_add_to_cache(table, index));
+	success = dict_index_add_to_cache(table, index, mtr_read_ulint(
+			dict_hdr + DICT_HDR_TABLES, MLOG_4BYTES, &mtr));
+	ut_a(success);
 	/*-------------------------*/
 	index = dict_mem_index_create("SYS_TABLES", "ID_IND",
 			DICT_HDR_SPACE, DICT_UNIQUE, 1);
 	dict_mem_index_add_field(index, "ID", 0, 0);
 
-	index->page_no = mtr_read_ulint(dict_hdr + DICT_HDR_TABLE_IDS,
-							MLOG_4BYTES, &mtr);
 	index->id = DICT_TABLE_IDS_ID;
-	ut_a(dict_index_add_to_cache(table, index));
+	success = dict_index_add_to_cache(table, index, mtr_read_ulint(
+			dict_hdr + DICT_HDR_TABLE_IDS, MLOG_4BYTES, &mtr));
+	ut_a(success);
 	/*-------------------------*/
 	table = dict_mem_table_create("SYS_COLUMNS", DICT_HDR_SPACE, 7, FALSE);
 
@@ -311,10 +312,10 @@ dict_boot(void)
 	dict_mem_index_add_field(index, "TABLE_ID", 0, 0);
 	dict_mem_index_add_field(index, "POS", 0, 0);
 
-	index->page_no = mtr_read_ulint(dict_hdr + DICT_HDR_COLUMNS,
-							MLOG_4BYTES, &mtr);
 	index->id = DICT_COLUMNS_ID;
-	ut_a(dict_index_add_to_cache(table, index));
+	success = dict_index_add_to_cache(table, index, mtr_read_ulint(
+			dict_hdr + DICT_HDR_COLUMNS, MLOG_4BYTES, &mtr));
+	ut_a(success);
 	/*-------------------------*/
 	table = dict_mem_table_create("SYS_INDEXES", DICT_HDR_SPACE, 7, FALSE);
 
@@ -347,10 +348,10 @@ dict_boot(void)
 	dict_mem_index_add_field(index, "TABLE_ID", 0, 0);
 	dict_mem_index_add_field(index, "ID", 0, 0);
 
-	index->page_no = mtr_read_ulint(dict_hdr + DICT_HDR_INDEXES,
-							MLOG_4BYTES, &mtr);
 	index->id = DICT_INDEXES_ID;
-	ut_a(dict_index_add_to_cache(table, index));
+	success = dict_index_add_to_cache(table, index, mtr_read_ulint(
+			dict_hdr + DICT_HDR_INDEXES, MLOG_4BYTES, &mtr));
+	ut_a(success);
 	/*-------------------------*/
 	table = dict_mem_table_create("SYS_FIELDS", DICT_HDR_SPACE, 3, FALSE);
 
@@ -368,10 +369,10 @@ dict_boot(void)
 	dict_mem_index_add_field(index, "INDEX_ID", 0, 0);
 	dict_mem_index_add_field(index, "POS", 0, 0);
 
-	index->page_no = mtr_read_ulint(dict_hdr + DICT_HDR_FIELDS,
-						MLOG_4BYTES, &mtr);
 	index->id = DICT_FIELDS_ID;
-	ut_a(dict_index_add_to_cache(table, index));
+	success = dict_index_add_to_cache(table, index, mtr_read_ulint(
+			dict_hdr + DICT_HDR_FIELDS, MLOG_4BYTES, &mtr));
+	ut_a(success);
 
 	mtr_commit(&mtr);
 	/*-------------------------*/

innobase/dict/dict0crea.c

@@ -544,9 +544,7 @@ dict_build_index_def_step(
 	table in the same tablespace */
 
 	index->space = table->space;
-
-	index->page_no = FIL_NULL;
-	
+	node->page_no = FIL_NULL;
 	row = dict_create_sys_indexes_tuple(index, node->heap);
 	node->ind_row = row;
 
@@ -624,18 +622,18 @@ dict_create_index_tree_step(
 
 	btr_pcur_move_to_next_user_rec(&pcur, &mtr);
 
-	index->page_no = btr_create(index->type, index->space, index->id,
+	node->page_no = btr_create(index->type, index->space, index->id,
 							table->comp, &mtr);
 	/* printf("Created a new index tree in space %lu root page %lu\n",
 					index->space, index->page_no); */
 
 	page_rec_write_index_page_no(btr_pcur_get_rec(&pcur),
 					DICT_SYS_INDEXES_PAGE_NO_FIELD,
-					index->page_no, &mtr);
+					node->page_no, &mtr);
 	btr_pcur_close(&pcur);
 	mtr_commit(&mtr);
 
-	if (index->page_no == FIL_NULL) {
+	if (node->page_no == FIL_NULL) {
 
 		return(DB_OUT_OF_FILE_SPACE);
 	}
@@ -793,7 +791,7 @@ dict_truncate_index_tree(
 
 	root_page_no = btr_create(type, space, index_id, comp, mtr);
 	if (index) {
-		index->page_no = root_page_no;
+		index->tree->page = root_page_no;
 	}
 
 	page_rec_write_index_page_no(rec,
@@ -857,6 +855,7 @@ ind_create_graph_create(
 	node->index = index;
 
 	node->state = INDEX_BUILD_INDEX_DEF;
+	node->page_no = FIL_NULL;
 	node->heap = mem_heap_create(256);
 
 	node->ind_def = ins_node_create(INS_DIRECT,
@@ -1076,7 +1075,8 @@ dict_create_index_step(
 
 	if (node->state == INDEX_ADD_TO_CACHE) {
 
-		success = dict_index_add_to_cache(node->table, node->index);
+		success = dict_index_add_to_cache(node->table, node->index,
+				node->page_no);
 
 		ut_a(success);
 

innobase/dict/dict0dict.c

@@ -1374,8 +1374,9 @@ dict_index_add_to_cache(
 /*====================*/
 				/* out: TRUE if success */
 	dict_table_t*	table,	/* in: table on which the index is */
-	dict_index_t*	index)	/* in, own: index; NOTE! The index memory
+	dict_index_t*	index,	/* in, own: index; NOTE! The index memory
 				object is freed in this function! */
+	ulint		page_no)/* in: root page number of the index */
 {
 	dict_index_t*	new_index;
 	dict_tree_t*	tree;
@@ -1461,10 +1462,9 @@ dict_index_add_to_cache(
 		tree = dict_index_get_tree(
 					UT_LIST_GET_FIRST(cluster->indexes));
 		new_index->tree = tree;
-		new_index->page_no = tree->page;
 	} else {
 		/* Create an index tree memory object for the index */
-		tree = dict_tree_create(new_index);
+		tree = dict_tree_create(new_index, page_no);
 		ut_ad(tree);
 
 		new_index->tree = tree;
@@ -1749,7 +1749,6 @@ dict_index_build_internal_clust(
 	new_index->n_user_defined_cols = index->n_fields;
 	
 	new_index->id = index->id;
-	new_index->page_no = index->page_no;
 
 	if (table->type != DICT_TABLE_ORDINARY) {
 		/* The index is mixed: copy common key prefix fields */
@@ -1928,7 +1927,6 @@ dict_index_build_internal_non_clust(
 	new_index->n_user_defined_cols = index->n_fields;
 	
 	new_index->id = index->id;
-	new_index->page_no = index->page_no;
 
 	/* Copy fields from index to new_index */
 	dict_index_copy(new_index, index, 0, index->n_fields);
@@ -3565,9 +3563,10 @@ dict_tree_t*
 dict_tree_create(
 /*=============*/
 				/* out, own: created tree */
-	dict_index_t*	index)	/* in: the index for which to create: in the
+	dict_index_t*	index,	/* in: the index for which to create: in the
 				case of a mixed tree, this should be the
 				index of the cluster object */
+	ulint		page_no)/* in: root page number of the index */
 {
 	dict_tree_t*	tree;
 
@@ -3577,7 +3576,7 @@ dict_tree_create(
 
 	tree->type = index->type;
 	tree->space = index->space;
-	tree->page = index->page_no;
+	tree->page = page_no;
 
 	tree->id = index->id;
 	

innobase/dict/dict0load.c

@@ -681,12 +681,10 @@ dict_load_indexes(
 		} else {
  			index = dict_mem_index_create(table->name, name_buf,
 						space, type, n_fields);
-			index->page_no = page_no;
 			index->id = id;
 		
 			dict_load_fields(table, index, heap);
-
-			dict_index_add_to_cache(table, index);
+			dict_index_add_to_cache(table, index, page_no);
 		}
 
 		btr_pcur_move_to_next_user_rec(&pcur, &mtr);

innobase/ibuf/ibuf0ibuf.c

@@ -548,11 +548,9 @@ ibuf_data_init_for_space(
 	dict_mem_index_add_field(index, "PAGE_NO", 0, 0);
 	dict_mem_index_add_field(index, "TYPES", 0, 0);
 
-	index->page_no = FSP_IBUF_TREE_ROOT_PAGE_NO;
-	
 	index->id = ut_dulint_add(DICT_IBUF_ID_MIN, space);
 
-	dict_index_add_to_cache(table, index);
+	dict_index_add_to_cache(table, index, FSP_IBUF_TREE_ROOT_PAGE_NO);
 
 	data->index = dict_table_get_first_index(table);
 

innobase/include/dict0crea.h

@@ -153,6 +153,7 @@ struct ind_node_struct{
 	/*----------------------*/
 	/* Local storage for this graph node */
 	ulint		state;	/* node execution state */
+	ulint		page_no;/* root page number of the index */
 	dict_table_t*	table;	/* table which owns the index */
 	dtuple_t*	ind_row;/* index definition row built */
 	ulint		field_no;/* next field definition to insert */

innobase/include/dict0dict.h

@@ -508,8 +508,9 @@ dict_index_add_to_cache(
 /*====================*/
 				/* out: TRUE if success */
 	dict_table_t*	table,	/* in: table on which the index is */
-	dict_index_t*	index);	/* in, own: index; NOTE! The index memory
+	dict_index_t*	index,	/* in, own: index; NOTE! The index memory
 				object is freed in this function! */
+	ulint		page_no);/* in: root page number of the index */
 /************************************************************************
 Gets the number of fields in the internal representation of an index,
 including fields added by the dictionary system. */
@@ -686,9 +687,10 @@ dict_tree_t*
 dict_tree_create(
 /*=============*/
 				/* out, own: created tree */
-	dict_index_t*	index);	/* in: the index for which to create: in the
+	dict_index_t*	index,	/* in: the index for which to create: in the
 				case of a mixed tree, this should be the
 				index of the cluster object */
+	ulint		page_no);/* in: root page number of the index */
 /**************************************************************************
 Frees an index tree struct. */
 

innobase/include/dict0mem.h

@@ -218,7 +218,6 @@ struct dict_index_struct{
 	const char*	table_name; /* table name */
 	dict_table_t*	table;	/* back pointer to table */
 	ulint		space;	/* space where the index tree is placed */
-	ulint		page_no;/* page number of the index tree root */
 	ulint		trx_id_offset;/* position of the the trx id column
 				in a clustered index record, if the fields
 				before it are known to be of a fixed size,

innobase/row/row0mysql.c

@@ -2455,12 +2455,20 @@ queries on the table.
 2) Purge and rollback: we assign a new table id for the table. Since purge and
 rollback look for the table based on the table id, they see the table as
 'dropped' and discard their operations.
-3) Insert buffer: we remove all entries for the table in the insert
-buffer tree; ... TODO
+3) Insert buffer: TRUNCATE TABLE is analogous to DROP TABLE, so we do not
+have to remove insert buffer records, as the insert buffer works at a low
+level.  If a freed page is later reallocated, the allocator will remove
+the ibuf entries for it.
+
+TODO: when we truncate *.ibd files (analogous to DISCARD TABLESPACE), we
+will have to remove we remove all entries for the table in the insert
+buffer tree!
+
 4) Linear readahead and random readahead: we use the same method as in 3) to
-discard ongoing operations.
+discard ongoing operations.  (This will only be relevant for TRUNCATE TABLE
+by DISCARD TABLESPACE.)
 5) FOREIGN KEY operations: if table->n_foreign_key_checks_running > 0, we
-do not allow the discard. We also reserve the data dictionary latch. */
+do not allow the TRUNCATE.  We also reserve the data dictionary latch. */
 
 	static const char renumber_tablespace_proc[] =
 	"PROCEDURE RENUMBER_TABLESPACE_PROC () IS\n"