Bug #64115 Wrong values for the NUMBER_PAGES_CREATED and NUMBER_PAGES_WRITTEN columns
Submitted: 23 Jan 2012 19:56 Modified: 16 Jul 2012 22:53
Reporter: Davi Arnaut (OCA) Email Updates:
Status: Closed Impact on me:
None 
Category:MySQL Server: InnoDB storage engine Severity:S3 (Non-critical)
Version:5.6 OS:Any
Assigned to: CPU Architecture:Any
Tags: INNODB_BUFFER_POOL_STATS

[23 Jan 2012 19:56] Davi Arnaut
Description:
The problem is that the value of the NUMBER_PAGES_CREATED and NUMBER_PAGES_WRITTEN columns of the INNODB_BUFFER_POOL_STATS are actually being set to the rate of pages created and written. Also, the NUMBER_PAGES_GET column is not being set at all.

How to repeat:
Select from the NUMBER_PAGES_WRITTEN column at one-second intervals.

Suggested fix:
@@ -2229,11 +2229,13 @@ i_s_innodb_stats_fill(
 
        OK(fields[IDX_BUF_STATS_PAGE_WRITTEN]->store(info->n_pages_written));
 
+       OK(fields[IDX_BUF_STATS_GET]->store(info->n_page_gets));
+
        OK(fields[IDX_BUF_STATS_PAGE_READ_RATE]->store(info->pages_read_rate));
 
-       OK(fields[IDX_BUF_STATS_PAGE_CREATED]->store(info->pages_created_rate));
+       OK(fields[IDX_BUF_STATS_PAGE_CREATE_RATE]->store(info->pages_created_rate));
 
-       OK(fields[IDX_BUF_STATS_PAGE_WRITTEN]->store(info->pages_written_rate));
+       OK(fields[IDX_BUF_STATS_PAGE_WRITTEN_RATE]->store(info->pages_written_rate));
 
        if (info->n_page_get_delta) {
                OK(fields[IDX_BUF_STATS_HIT_RATE]->store(
[23 Jan 2012 21:46] Davi Arnaut
Also, it is worth renaming IDX_BUF_STATS_PENDING_ZIP to IDX_BUF_STATS_PENDING_UNZIP.
[24 Jan 2012 5:07] Valeriy Kravchuk
Thank you for the bug report. Verified just as described:

...
mysql> insert into test.tinno(c2) select c2 from test.tinno;
Query OK, 4096 rows affected (0.72 sec)
Records: 4096  Duplicates: 0  Warnings: 0

mysql> select number_pages_written from innodb_buffer_pool_stats;
+----------------------+
| number_pages_written |
+----------------------+
|                   31 |
+----------------------+
1 row in set (0.00 sec)

mysql> select number_pages_written from innodb_buffer_pool_stats;
+----------------------+
| number_pages_written |
+----------------------+
|                    0 |
+----------------------+
1 row in set (0.00 sec)
[16 Jul 2012 22:53] John Russell
Added to changelog for 5.6.7, 5.7.0: 

The value of the NUMBER_PAGES_CREATED and NUMBER_PAGES_WRITTEN
columns of the INFORMATION_SCHEMA.INNODB_BUFFER_POOL_STATS table were
set to incorrect values, and the NUMBER_PAGES_GET column was not
being set at all.