CSV imports fail - stalling In Progress, Runtime Less than 1 second

Product Support
15

What is the role of lead_event_log in importing via CSV?

I tried to change collation of that table to utf8mb4_general_ci via PHPMyAdmin, but get a ‘foreign key contraint incorrectly formed’ error message.

When I try to downgrade (?) that table from InnoDB to MYISAM I get this error message:

Error
Static analysis:

1 errors were found during analysis.

Missing comma before start of a new alter operation. (near "DEFAULT CHARSET" at position 51)
SQL query: Edit Edit

ALTER TABLE `mtc_lead_event_log` ENGINE = MYISAM DEFAULT CHARSET=utf8 COLLATE utf8_unicode_ci;

MySQL said: Documentation

#1071 - Specified key was too long; max key length is 1000 bytes

I tried ‘Optimize table’ in PHPMyAdmin, which returned this unhelpful message:

username_mautic.lead_event_log	optimize	note	Table does not support optimize, doing recreate + ...
username_mautic.lead_event_log	optimize	status	OK

‘… recreate + …’ is apparently ‘… recreate + analyze instead’.

And lo and behold, after two months without any useful help/hints from Mautic developers, it actually seems to have fixed my problem; import of the most basic CSV now results in ‘Runtime 2 seconds, Progress 100%, 2 inserted, 43 updated’.