Fix busy-wait on client SSL connection #4588
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Errors and EOF returned by 'recv' are now properly handled, isolated
from the return value ('r') from the later and conditional 'SSL_read'.
Previously, a busy loop was possible in the following scenario:
1. A client connection was closed, leading to a return of 0 by 'recv',
and 'errno' to be set with 'EAGAIN'.
2. Error handling is performed taking into account a never performed
call to 'SSL_read' (as if this '0' was a result for this call).
3. The call to 'SSL_get_error' returns with 'SSL_ERROR_SYSCALL', as a
result of using this invalid param of '0' (which for 'SSL_read' would
mean non-retryable error), and the non-reset 'errno' would still be
'EAGAIN'.
4. This would create the illusion of an interrupted read. So a new read
is tried again, while in reality the socket is closed. This busy loop
will continue until 'POLLHUP' is received when we attempt to write
back to the client and a 'RST' is received as a response.
Several calls inside 'proxy_debug_func' (specially if database logging is enabled) could alter 'errno', which could influence error handling.
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retest this please |
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retest this please |
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- Ensure new values has been written to 'system_cpu'. - Use the correct (runtime) interval for the computation. - Issue warning when supplied interval != runtime (rounded value).
Variables specifying timing intervals, like 'stats_mysql_connections', may get rounded to the closer, valid time interval. Now a warning is issued for making the user aware of this rounding operation.
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retest this please |
Some tests assume ProxySQL should be in an idle state, only affected by either idle connections or monitoring actions. This idle state could be perturbed by the continuous actions of the scheduler in Core Cluster nodes.
- Simplified and unified condition waiting checks. - Added new helper function for fetching cluster core nodes.
- Refactor nodes fetching using new helper functions. - Simplified and documented 'plan' tests count computation. - Other minor cleanups.
Test is now aware of 'cluster_mysql_servers_sync_algorithm'. In case of 'runtime_mysql_servers' propagation, the test disables monitoring since it creates servers in hostgroups with active monitoring, if config doesn't allows 'runtime' propagation, the test assumes everything will just work. This should be a common pattern for tests creating fake servers.
- Adds config option with microseconds resolution, ON by default. - Preserves TAP convention for messages to prevent tooling breaking.
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This list hold tracking errors that in practice are equivalent to ER_UNKNOWN_SYSTEM_VARIABLE and that we want to handle in the same way.
JavierJF
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Simplify scheduler code disabling/enabling for Cluster Core nodes.
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Main Fix
This PR fixes the following busy-loop scenario when handling SSL client connections, the description is in terms of reads handling within
MySQL_Data_Stream::read_from_netfunction:Minor Fix
This PR makes
proxy_debug_funcsave/restore theerrnovalue. This can prevent issues of logging influencing error handling.Extra fixes