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

1 files changed, 12 insertions, 4 deletions

diff --git a/innobase/row/row0mysql.c b/innobase/row/row0mysql.c
index a9b9d096e6b..6aaa0cbcf1b 100644
--- a/innobase/row/row0mysql.c
+++ b/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"