Bug #67857 Document about InnoDB Full-Text Search has mistakes
Submitted: 10 Dec 2012 6:56 Modified: 1 Feb 2013 18:45
Reporter: tsubasa tanaka (OCA) Email Updates:
Status: Closed Impact on me:
None 
Category:MySQL Server: Documentation Severity:S3 (Non-critical)
Version:5.6.8 OS:Any
Assigned to: John Russell CPU Architecture:Any
Tags: doc, fts, innodb

[10 Dec 2012 6:56] tsubasa tanaka
Description:
I seem some describes about valiables of InnoDB FullText-Search has differences from server behavior.

o- innodb_ft_cache_size is described "Dynamic Variable" but It can't be changed dynamically.

o- Default Value of innodb_ft_cache_size is described 33554432(32MiB) but it shows 32000000(32 * 10^6).

o- innodb_ft_max_token_size is described "Dynamic Variable" but It can't be changed dynamically.

o- innodb_ft_min_token_size is described "Dynamic Variable" but It can't be changed dynamically.

o- innodb_ft_sort_pll_degree is described "Dynamic Variable" but It can't be changed dynamically.

How to repeat:
mysql> show variables like 'innodb_ft%';
+---------------------------------+----------+
| Variable_name                   | Value    |
+---------------------------------+----------+
| innodb_ft_aux_table             |          |
| innodb_ft_cache_size            | 32000000 |
| innodb_ft_enable_diag_print     | OFF      |
| innodb_ft_enable_stopword       | ON       |
| innodb_ft_max_token_size        | 84       |
| innodb_ft_min_token_size        | 3        |
| innodb_ft_num_word_optimize     | 2000     |
| innodb_ft_server_stopword_table |          |
| innodb_ft_sort_pll_degree       | 2        |
| innodb_ft_user_stopword_table   |          |
+---------------------------------+----------+
10 rows in set (0.03 sec)

mysql> set global innodb_ft_cache_size = 16 * 1024 * 1024;
ERROR 1238 (HY000): Variable 'innodb_ft_cache_size' is a read only variable

mysql> set global innodb_ft_max_token_size = 10;
ERROR 1238 (HY000): Variable 'innodb_ft_max_token_size' is a read only variable

mysql> set global innodb_ft_min_token_size = 1;
ERROR 1238 (HY000): Variable 'innodb_ft_min_token_size' is a read only variable

mysql> set global innodb_ft_sort_pll_degree = 32;
ERROR 1238 (HY000): Variable 'innodb_ft_sort_pll_degree' is a read only variable

Suggested fix:
Maybe document's mistake.
[10 Dec 2012 12:14] MySQL Verification Team
Thank you for the bug report.
[1 Feb 2013 18:44] John Russell
Fixed the reference info for these options. Good catch.

The default for innodb_ft_cache_size changes in 5.6.10, but the new value is also a round number rather than a power of 2, so it needed to be corrected also in the doc.