Timeline for Why does Table Definitions Opened differ this much between cluster nodes?
Current License: CC BY-SA 3.0
13 events
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| Jan 12, 2016 at 11:00 | comment | added | Fred Asp |
No its just a check that checks a comment in each table with (show create table ) that checks the correlation between code-trunk and db. Unfortunately some "special" (severely above my paygrade) devs have access to everything. I see a typo in my earlier answer it was the table_definition_cache I changed. Not the table_open_cache. Yep, me and my company have a lot more to learn in all this. Thank alot. It was appreciating .
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| Jan 11, 2016 at 18:08 | comment | added | Rick James |
Do the devs have alter and create... privileges? Removing that would eliminate their ability to make changes?
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| Jan 11, 2016 at 18:05 | comment | added | Rick James | 50 checks/sec is possibly a big burden on the system. | |
| Jan 11, 2016 at 13:16 | vote | accept | Fred Asp | ||
| Jan 11, 2016 at 13:16 | comment | added | Fred Asp |
Right on. table_open_cache = 2000 so i doubled it and the charts flat lined directly. We do some integrity tests on the databases as a last line of defence against the developers ;-) It checks the table structures so they haven't been changed and that they are up to date. Thanks for the answer.
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| Jan 7, 2016 at 17:04 | comment | added | Rick James |
Note: Some 3rd party software products do "dumb" things like SHOW CREATE TABLE before every statement. Are you calling MySQL directly, or using 3rd party software?
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| Jan 7, 2016 at 16:04 | comment | added | Rick James |
The STATUS value Opened_table_definitions increments by 1 when doing SHOW CREATE TABLE -- if that table in not already in the table_open_cache. So, how many tables do you have? What is the setting of the VARIABLE table_open_cache on each machine? And why are you doing SHOW CREATE TABLE so often, apparently on only one node?
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| Jan 7, 2016 at 8:33 | comment | added | Fred Asp | I might have found it. Could a SHOW CREATE TABLE spark a 'Table Definitions Opened'? | |
| Jan 7, 2016 at 7:31 | comment | added | Rick James | "Connections" and "tables opened" are separate things. | |
| Jan 7, 2016 at 7:28 | comment | added | Fred Asp | Otherwise they are all load balanced so number of connections should be similar for all the nodes. | |
| Jan 7, 2016 at 7:26 | comment | added | Rick James | Are all writes going to one node? | |
| Jan 7, 2016 at 7:22 | comment | added | Fred Asp | Yep, they are exactly the same. Well it could have been that one we bootstrapped the cluster with. | |
| Jan 5, 2016 at 18:30 | history | answered | Rick James | CC BY-SA 3.0 |