SQL Plan Directives: Gotta Purge ‘Em All

A tip I picked up from Nigel Bayliss regards purging SQL Plan Directives, I’ve been using it a lot recently and can’t see it documented elsewhere. As some background these records, exposed via the DBA_SQL_PLAN_DIRECTIVES view, are cardinality corrections created and used when running with Adaptive Statistics enabled.  There is a job that should automatically …

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Adding a little TLS complexity to authentication_ldap_simple

In a previous post I showed that by default when authentication_ldap_simple communicates with a Windows Domain Controller (or any other LDAP service), then the password is transmitted unencrypted during authentication. This time I’ll demonstrate how to close this loophole.  A pre-requisite is that the Domain Controller needs to be configured to accept secure connections. This is …

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(MySQL) Logged and Loaded: authentication_ldap_simple_log_status or authentication_ldap_sasl_log_status not effective?

A quick one in case anyone else hits the same problem as I encountered.  The documentation for authentication_ldap_sasl_log_status and  authentication_ldap_simple_log_status states these variables can be set to a value between 1 and 5 to control the types of messages logged. If you set them and still find nothing is logged then sett log_error_verbosity to it’s maximum value of …

(MySQL) Logged and Loaded: authentication_ldap_simple_log_status or authentication_ldap_sasl_log_status not effective? Read More »

Let the wrong one in! MySQL AD Authentication with authentication_ldap_simple

I mentioned in my previous blog entry that had I encountered an issue with this plugin, and I think now that it has been fixed in the latest MySQL versions (released on 2019-04-25) it’s reasonable to share my findings. The following tests are with MySQL Version 8.0.13. I start by installing the plugin, pointing it …

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mysql_clear_password & authentication_ldap_simple password encryption

Preparing for my talk at the HK Open Source Conference I wanted to confirm some of the things I had read about these plugins, mostly from Matthias Crauwels excellent article on the subject. My lab environment consists of Windows 2016 Domain controller and client machines, with MySQL 8 running on Oracle Linux 7. First I …

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Resource manager session_pga_limit has it’s own limits

Recently we hit an issue with a complex SQL statement (formatted was 44,000 lines, maybe subject of a separate blog post), causing the CBO to struggle consuming large amounts of PGA memory, and the host to start swapping memory and impacting other database users. The pga_aggregate_limit parameter did not appear to be kicking in (maybe …

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