Please post your query here ksizemor

Here's what I've pulled from the mysql general log. These queries are being run when the errors above appear. During that short period MaxScale also stops responding and the website locks up.

START TRANSACTION;
INSERT INTO `catalogsearch_query` (`query_text`, `popularity`, `store_id`, `is_active`, `is_processed`, `updated_at`, `ip_address`) VALUES ('Blackhawk!', '1', '1', '0', '0', '2018-02-24 01:34:49', '12.69.234.140');
COMMIT;

START TRANSACTION;
UPDATE `catalogsearch_query` SET `query_text` = 'Blackhawk!', `popularity` = '1', `store_id` = '1', `is_active` = '1', `is_processed` = '0', `updated_at` = '2018-02-24 01:34:49', `ip_address` = '12.69.234.140' WHERE (query_id='470135');
COMMIT;

START TRANSACTION;
UPDATE `catalogsearch_query` SET `query_text` = 'Blackhawk!', `num_results` = '0', `popularity` = '1', `store_id` = '1', `is_active` = '1', `is_processed` = '1', `updated_at` = '2018-02-24 01:34:49', `ip_address` = '12.69.234.140' WHERE (query_id='470135');
COMMIT;

SELECT `main_table`.* FROM `m_searchsphinx_synonym` AS `main_table` WHERE (FIND_IN_SET('Blackhawk!', synonyms));

SELECT `main_table`.* FROM `m_searchsphinx_stopword` AS `main_table` WHERE (`word` = 'Blackhawk!') AND (`store` = '1');

START TRANSACTION;
UPDATE `catalogsearch_query` SET `query_text` = 'Blackhawk!', `num_results` = '0', `popularity` = '1', `store_id` = '1', `is_active` = '1', `is_processed` = '1', `updated_at` = '2018-02-24 01:34:49', `ip_address` = '12.69.234.140' WHERE (query_id='470135');
COMMIT;

SELECT `core_url_rewrite`.* FROM `core_url_rewrite` WHERE (request_path IN ('catalogsearch/ajax/suggest/?q=blackhawk!','catalogsearch/ajax/suggest?q=Blackhawk!', 'catalogsearch/ajax/suggest/', 'catalogsearch/ajax/suggest')) AND (store_id IN(0, 1));

SELECT `main_table`.* FROM `m_searchlandingpage` AS `main_table` WHERE (`query_text` = 'Blackhawk!') AND (`is_active` = '1') AND (EXISTS (SELECT * FROM `m_searchlandingpage_store`
AS `page_store_table`
WHERE main_table.page_id = page_store_table.page_id
AND page_store_table.store_id in (0, '1')));

SELECT `catalogsearch_query`.* FROM `catalogsearch_query` WHERE (store_id = '1') AND (query_text = 'Blackhawk!') UNION ALL (SELECT `catalogsearch_query`.* FROM `catalogsearch_query` WHERE (store_id = '1') AND (synonym_for = 'Blackhawk!')) ORDER BY `synonym_for` ASC LIMIT 1;

SELECT DISTINCT IFNULL(synonym_for, query_text) AS `query`, `main_table`.`num_results`, `main_table`.* FROM `catalogsearch_query` AS `main_table` WHERE (num_results > 0 AND display_in_terms = 1 AND query_text LIKE 'Blackhawk!%') AND (store_id = 1) ORDER BY `popularity` DESC;

I have rolled back to MaxScale 2.1 where it works fine. This started immediately after updating to 2.2.

This appears to be triggered by a closed connection after a temporary table is created.

To be more precise, the error message is triggered by the creation of a temporary table. We haven't been able to reproduce the lockup that you've described.

I have looked at Kathryn's system and examined her general query log. Of the queries she listed above, only the SELECT statements are working. The UPDATE and INSERT statements never make it through MaxScale to the database. MaxScale is not parsing these correctly and never sends them to MariaDB. This causes her website to hang waiting for a reply.

She is using the Magento E-Commerce framework version 1.9 without any changes to the core. This problem surfaced as a result of the upgrade to MaxScale 2.2.

While her example involves a website, I do not believe the source of the query matters. They are properly formed queries and MaxScale should understand them regardless of her application.

This is only the case when the use of a special character is included in the string.

As you can see from her notes above, all of her WRITE statements are wrapped in START TRANSACTION/COMMIT. I don't know if that is related or not but it's worth noting.

When a search is performed using a keyword without a special character (example: "Yahoo"), a result IS returned by MariaDB and MaxScale logs these TWO errors:

[qc_sqlite] The query could not be parsed. Response not valid.
[qc_sqlite] The provided buffer does not contain a COM_QUERY, but a COM_QUIT.

But, when a special character is added to the query (example: "Yahoo!"), a result is NOT returned by MariaDB and MaxScale hangs on the first error:

[qc_sqlite] The query could not be parsed. Response not valid.

There has to be some sofar unknown component affecting the result. Namely, those insert/update transactions are handled just fine when executed using mysql tool.

toddstoffel Which operating system is used?

Would it be possible to get the full MaxScale log?

Please try if it works when only the master server is configured for the readwritesplit service. If this works, it would suggest that a SELECT to a temporary table is done and the returned error causes problem on the client end.

@Johan, the MaxScale node is running on CentOS 7 and the two MariaDB nodes are running on Ubuntu 16.04.4 LTS

ksizemor and toddstoffel: As the query parsing errors have been fixed, could you create a separate issue for any other problems? This way we can have one bug report per issue.

Closing as fixed as the bug that the issue describes was fixed. If you still have other problems, please open separate issues for them.