Execution of session commands failed because session commands and normal sql statements were executed in a wrong order if backend was executing previous session command while new sql stmt was routed to that backend. There was a window where ordering went wrong.
It is possible that one normal sql stmt arrives while previous sescmds are still being executed.
Introduced a new member in backend_ref_t structure, bref_pending_cmd where new sql stmt pointer is stored in that case. When sescmds are executed completely, that command is automatically executed next.
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