# QAN not showing examples and explains
**URL:** https://forums.percona.com/t/qan-not-showing-examples-and-explains/19607
**Category:** PMM 2.x
**Created:** [January 13, 2023, 8:32am UTC](https://forums.percona.com/t/qan-not-showing-examples-and-explains/19607 "2023-01-13T08:32:04Z")
**Posts on this page:** 13
**Page:** 1
### Author:  [@justas](https://forums.percona.com/u/justas)
#### Post date: [January 13, 2023, 8:32am UTC](https://forums.percona.com/t/qan-not-showing-examples-and-explains/19607/1 "2023-01-13T08:32:04Z")
Hi, we’re using PMM on percona 8.0 DB. Problem that QAN dashboard do not show some SQL queries examples and explains. We’re increased variable values as instructed on [[PMM-6692] Cannot see long queries - Percona JIRA](https://jira.percona.com/browse/PMM-6692)
```auto
+--------------------------------------+-------+
| Variable_name | Value |
+--------------------------------------+-------+
| max_digest_length | 4000 |
| performance_schema_max_digest_length | 4000 |
+--------------------------------------+-------+
```
But that didn’t help. PMM user has following permissions
```auto
+------------------------------------------------------------------------------+
| Grants for pmm@% |
+------------------------------------------------------------------------------+
| GRANT SELECT, RELOAD, PROCESS, SUPER, REPLICATION CLIENT ON *.* TO `pmm`@`%` |
| GRANT SELECT, UPDATE, DELETE, DROP ON `performance_schema`.* TO `pmm`@`%` |
+------------------------------------------------------------------------------+
```
---
### Author:  [@Ankit\_Kapoor1](https://forums.percona.com/u/Ankit_Kapoor1)
#### Post date: [January 13, 2023, 9:51am UTC](https://forums.percona.com/t/qan-not-showing-examples-and-explains/19607/2 "2023-01-13T09:51:21Z")
Hi @justas ,
Thanks for reaching out.My name is Ankit and I am here to help you. I understand that you are not able to see some queries on QAN dashboard. Can you please elaborate what queries are not visible on QAN ? Is there some specific set of queries ?
---
### Author:  [@justas](https://forums.percona.com/u/justas)
#### Post date: [January 13, 2023, 11:23am UTC](https://forums.percona.com/t/qan-not-showing-examples-and-explains/19607/3 "2023-01-13T11:23:48Z")
Hi, thanks for your response. I can see queries but they do not have Examples/ Explains
```auto
Sorry, no examples found for this query
```
```auto
No classic explain found
No JSON explain found
No table info from example nor explain
```
---
### Author:  [@Pep\_Pla](https://forums.percona.com/u/Pep_Pla)
#### Post date: [January 15, 2023, 9:42pm UTC](https://forums.percona.com/t/qan-not-showing-examples-and-explains/19607/4 "2023-01-15T21:42:06Z")
Hi @justas
It would be great if you could provide us with the following information:
- Version of PMM
- Consumers enabled (select \* from performance\_schema.setup\_consumers)
- Properly anonymized versions of:
- Query that shows the explain properly (if any)
- Query that does not show the explain
- Are you using targeting only one database?
Thank you!
Pep
---
### Author:  [@matthewb](https://forums.percona.com/u/matthewb)
#### Post date: [January 16, 2023, 1:24am UTC](https://forums.percona.com/t/qan-not-showing-examples-and-explains/19607/5 "2023-01-16T01:24:12Z")
@justas, can you please confirm that when you ran `pmm-admin add mysql` that you specified the performance\_schema as the source for slow queries?
---
### Author:  [@justas](https://forums.percona.com/u/justas)
#### Post date: [January 16, 2023, 9:06am UTC](https://forums.percona.com/t/qan-not-showing-examples-and-explains/19607/6 "2023-01-16T09:06:24Z")
Database was added using UI so it is using performance\_schema.
```auto
PMMVersion: 2.31.0
```
```auto
mysql> select * from performance_schema.setup_consumers;
+----------------------------------+---------+
| NAME | ENABLED |
+----------------------------------+---------+
| events_stages_current | NO |
| events_stages_history | NO |
| events_stages_history_long | NO |
| events_statements_current | YES |
| events_statements_history | YES |
| events_statements_history_long | YES |
| events_transactions_current | YES |
| events_transactions_history | YES |
| events_transactions_history_long | NO |
| events_waits_current | NO |
| events_waits_history | NO |
| events_waits_history_long | NO |
| global_instrumentation | YES |
| thread_instrumentation | YES |
| statements_digest | YES |
+----------------------------------+---------+
```
Working query
```auto
SELECT
`t0`.`column0` AS `column0_1`,
`t0`.`column1` AS `column1_2`,
`t0`.`column2` AS `column2_3`,
`t0`.`column3` AS `column3_4`,
`t0`.`column4` AS `column4_5`,
`t0`.`column5` AS `column5_6`,
`t0`.`column6` AS `column6_7`,
`t0`.`column7` AS `column7_8`,
`t0`.`column8` AS `column8_9`,
`t0`.`column9` AS `column9_10`,
`t0`.`column10` AS `column10_11`,
`t0`.`column11` AS `column11_12`,
`t0`.`column12` AS `column12_13`,
`t0`.`column13` AS `column13_14`,
`t0`.`column14` AS `column14_15`
FROM
`column1_column2` `t0`
WHERE
`t0`.`column12` = ?
AND `t0`.`column13` = ?
AND `t0`.`column14` = ?
```
Not working query
```auto
SELECT
`b0_`.`column0` AS `column0_0`,
`b0_`.`column1` AS `column1_1`,
`b0_`.`column3` AS `column3_2`,
`b0_`.`column4` AS `column4_3`,
`b0_`.`column5` AS `column5_4`,
`b0_`.`column6` AS `column6_5`,
`b0_`.`column7` AS `column7_6`,
`b0_`.`column8` AS `column8_7`,
`b0_`.`column9` AS `column9_8`,
`b0_`.`column10` AS `column10_9`,
`b0_`.`column11` AS `column11_10`,
`b0_`.`column12` AS `column12_11`,
`b0_`.`column13` AS `column13_12`,
`b0_`.`column14` AS `column14_13`,
`b0_`.`column15` AS `column15_14`,
`b0_`.`column16` AS `column16_15`,
`b0_`.`column17` AS `column17_16`,
`b0_`.`column18` AS `column18_17`,
`b0_`.`column19` AS `column19_18`,
`b0_`.`column20` AS `column20_19`
FROM
`table` `b0_`
LEFT JOIN `table0` `b1_` ON `b0_`.`column0` = `b1_`.`table_column0`
LEFT JOIN `table1` `b2_` ON `b0_`.`column0` = `b2_`.`table_column0`
LEFT JOIN `table2` `t3_` ON `b1_`.`table4_string` = `t3_`.`string`
LEFT JOIN `table2` `t4_` ON `b2_`.`table2_string` = `t4_`.`string`
LEFT JOIN `table3` `t5_` ON `b1_`.`table3_string` = `t5_`.`string`
WHERE
`b0_`.`column4` < ?
AND (
(
`b0_`.`column8` IS NULL
OR `b0_`.`column8` < ?
)
)
AND `b0_`.`column18` = ?
AND `b0_`.`column10` = ?
AND `b0_`.`column11` IN (...)
AND (
(
(
`t5_`.`string` IS NOT NULL
AND `t5_`.`column18` = ?
)
OR `t5_`.`string` IS NULL
)
)
AND (
(
(
`t3_`.`string` IS NOT NULL
AND `t3_`.`column18` = ?
)
OR `t3_`.`string` IS NULL
)
)
AND (
(
(
`t4_`.`string` IS NOT NULL
AND `t4_`.`column18` = ?
)
OR `t4_`.`string` IS NULL
)
)
```
We’re connected multiple databases to PMM.
---
### Author:  [@matthewb](https://forums.percona.com/u/matthewb)
#### Post date: [January 16, 2023, 8:39pm UTC](https://forums.percona.com/t/qan-not-showing-examples-and-explains/19607/7 "2023-01-16T20:39:29Z")
Did you pull the two query examples above from the ‘Examples’ tab in PMM? “Very long” queries (IIRC, over 1000 characters) are truncated by MySQL’s performance\_schema. Since PMM reads the data from P\_S, if P\_S truncates, then PMM also sees truncated and thus cannot parse it to show you EXPLAIN and TABLES data.
---
### Author:  [@justas](https://forums.percona.com/u/justas)
#### Post date: [January 17, 2023, 6:54am UTC](https://forums.percona.com/t/qan-not-showing-examples-and-explains/19607/8 "2023-01-17T06:54:48Z")
Hi, I pulled those queries from little _i_ symbol next to query. As I mentioned problem is that examples/explain are empty for mentioned query. At first it was truncated, but after increasing _max\_digest\_length_ now it shows full query.
---
### Author:  [@matthewb](https://forums.percona.com/u/matthewb)
#### Post date: [January 17, 2023, 2:18pm UTC](https://forums.percona.com/t/qan-not-showing-examples-and-explains/19607/9 "2023-01-17T14:18:18Z")
> [@justas](#):
>
> after increasing _max\_digest\_length_ now it shows full query.
After you did this, do explain/tables tabs now work?
---
### Author:  [@justas](https://forums.percona.com/u/justas)
#### Post date: [January 17, 2023, 2:20pm UTC](https://forums.percona.com/t/qan-not-showing-examples-and-explains/19607/10 "2023-01-17T14:20:23Z")
No, examples/explains still empty.
---
### Author:  [@tadrim](https://forums.percona.com/u/tadrim)
#### Post date: [February 22, 2023, 8:41am UTC](https://forums.percona.com/t/qan-not-showing-examples-and-explains/19607/12 "2023-02-22T08:41:07Z")
Solution:
Add mysql config to: /etc/mysql/my.cnf
Config:
```auto
[mysqld]
max_digest_length = 20240
performance_schema_max_digest_length = 20240
performance_schema_max_sql_text_length = 20240
```
---
### Author:  [@Maksim\_Kopachovets](https://forums.percona.com/u/Maksim_Kopachovets)
#### Post date: [March 27, 2023, 12:48pm UTC](https://forums.percona.com/t/qan-not-showing-examples-and-explains/19607/13 "2023-03-27T12:48:12Z")
Hi
There is a similar problem in QAN bookmarks
Examples, explain, tables - empty
added to config
max\_digest\_length = 20240
performance\_schema\_max\_digest\_length = 20240
performance\_schema\_max\_sql\_text\_length = 20240
did not help for tables, for Examples and Explain work only for small query
Basically a problem with large queries, small query displays.
---
### Author:  [@Maksim\_Kopachovets](https://forums.percona.com/u/Maksim_Kopachovets)
#### Post date: [April 25, 2023, 7:21am UTC](https://forums.percona.com/t/qan-not-showing-examples-and-explains/19607/14 "2023-04-25T07:21:54Z")
helped change source to slow query log
