If I "Repair" the DB, from cPanel, is that a straightforward event, or are there other post-repair Elgg steps that I should expect to take (e.g. run upgrade.php or something else)?

rjcal, cim, ... Thanks for your guidance. Just Repaired DB. Here is the message (my bolding):

sslego_elgg239 is now being repaired.

sslego_elgg239.elgg_access_collection_membership   OK
sslego_elgg239.elgg_access_collections             OK
sslego_elgg239.elgg_annotations                    OK
sslego_elgg239.elgg_api_users                      OK
sslego_elgg239.elgg_config                         OK
sslego_elgg239.elgg_datalists                      OK
sslego_elgg239.elgg_entities                       OK
sslego_elgg239.elgg_entity_relationships           OK
sslego_elgg239.elgg_entity_subtypes                OK
sslego_elgg239.elgg_geocode_cache
note     : The storage engine for the table doesn't support repair
sslego_elgg239.elgg_groups_entity                  OK
sslego_elgg239.elgg_hmac_cache
note     : The storage engine for the table doesn't support repair
sslego_elgg239.elgg_metadata                       OK
sslego_elgg239.elgg_metastrings                    OK
sslego_elgg239.elgg_objects_entity                 OK
sslego_elgg239.elgg_private_settings               OK
sslego_elgg239.elgg_river                          OK
sslego_elgg239.elgg_sites_entity                   OK
sslego_elgg239.elgg_system_log                     OK
sslego_elgg239.elgg_system_log_1283978602          OK
sslego_elgg239.elgg_system_log_1286398078          OK
sslego_elgg239.elgg_system_log_1288817293          OK
sslego_elgg239.elgg_system_log_1288817297          OK
sslego_elgg239.elgg_system_log_1288817298          OK
sslego_elgg239.elgg_system_log_1288817299          OK
sslego_elgg239.elgg_system_log_1291236506          OK
sslego_elgg239.elgg_system_log_1293655780          OK
sslego_elgg239.elgg_users_apisessions
note     : The storage engine for the table doesn't support repair
sslego_elgg239.elgg_users_entity                   OK
sslego_elgg239.elgg_users_sessions
info     : Found block that points outside data file at 228228
warning  : Number of rows changed from 80 to 173
status   : OK

Repair Complete

Ok. I can log in now. Thanks very much, rjcal and cim.

Is the general lesson learned here "Do not hesitate to check and repair the database?"

you're welcome Stephen! Anytime =)

Yes, always check for databases errors and repair your tables. Cheers =)

Rodolfo Hernandez
Arvixe/Elgg Community Liaison

Elgg uses the MyISAM table engine because it supports full text search. One downside is that tables can be corrupted by a crash. It looked like something like that happened with the session table. Glad to hear you got it working again. Kudos to rjcalifornia and Cim for helping out.

Also, to be clear, 1.7.6 does not have any changes that would contribute to this.

Thanks for the info, Cash.

As a non-expert, it can be hard to predict what steps are safe & easy, versus those that are fraught with danger and might foul everything up.

It's good to know that repairing a DB is not a big deal.

After repairing my database (I had the same error and the same log!), I can authenticate me, but the site is incomplete.My database is imposible to clean completly?