Pet losing some - not all - his gear

[noudess]

Looking for some feedback on what I am seeing.

I don't see where we're corrupting yet, but I find this odd.

Instrumentation:

- I have log messages in ~NPC and in the spot where the pet gets his gear restored.

Steps:

- Fresh server restart
- Login with existing pet to zone 1.
- I see the pet gear restore loop run fine.
- #zone to zone 2
- I see the pet gear restore loop run fine.
- #zone to zone 1 again.
- The process for zone1 hits the ~NPC code for the pet
- I see the pet gear restore fine after this.

Isn't it odd that the ~NPC code for the pet runs when I reenter the original zone and not when I leave one?

[noudess]

Ok....

It looks like the zone you are leaving stores the pets inventory into the DB using a loop of inserts. The zone you are entering retrieves the list with a single select.

Sometimes, depending on how fast you zone and how many items are in the pets inventory list, the receiving zone does the select before the sending zone has finished putting the items in.

I added a LOCK TABLES character_pet_inventory WRITE on the side saving the data, along with a release after the loop of inserts. I then added a LOCK TABLES READ on the destination zone's code to reload the data with the select.

I zoned 25 times and it has not failed with 12 pet items. That's never happened for me before, so I think that got it.

I'll post the code after a week or so of testing.

[noudess]

Patch code below:

***************
*** 2440,2459 ****
--- 2440,2464 ----
  				errbuf);
  			safe_delete_array(query);
  		}
  	}
  
+ 	database.RunQuery(query, MakeAnyLenString(&query, "LOCK TABLES `character_pet_inventory` WRITE", errbuf));
+ 	printf(errbuf);
+ 
  	for(i=0; i<MAX_WORN_INVENTORY; i++) {
  		if(petinfo->Items[i]) {
  			database.RunQuery(query, MakeAnyLenString(&query,
  				"INSERT INTO `character_pet_inventory` (`char_id`, `pet`, `slot`, `item_id`) values (%u, 0, %u, %u)",
  				c->CharacterID(), i, petinfo->Items[i]), errbuf);
  			// should check for errors
  			safe_delete_array(query);
  		}
  	}
  
+ 	database.RunQuery(query, MakeAnyLenString(&query,"UNLOCK TABLES", errbuf));
+ 	printf(errbuf);
  	
  	if(!database.RunQuery(query, MakeAnyLenString(&query,
  		"INSERT INTO `character_pet_info` (`char_id`, `pet`, `petname`, `petpower`, `spell_id`, `hp`, `mana`) "
  		"values (%u, 1, '%s', %u, %u, %u, %u) "
  		"ON DUPLICATE KEY UPDATE `petname`='%s', `petpower`=%i, `spell_id`=%u, `hp`=%u, `mana`=%u",
***************
*** 2581,2590 ****
--- 2586,2598 ----
  		LogFile->write(EQEMuLog::Error, "Error in LoadPetInfo query '%s': %s", query, errbuf);
  		safe_delete_array(query);
          return;
  	}
  
+ 	database.RunQuery(query, MakeAnyLenString(&query, "LOCK TABLES `character_pet_inventory` WRITE", errbuf));
+ 	printf(errbuf);
+ 
  	if (database.RunQuery(query, MakeAnyLenString(&query,
  		"SELECT `pet`, `slot`, `item_id` FROM `character_pet_inventory` WHERE `char_id`=%u",
  		c->CharacterID()), errbuf, &result))
  	{
  		safe_delete_array(query);
***************
*** 2608,2614 ****
--- 2616,2625 ----
  	else {
  		LogFile->write(EQEMuLog::Error, "Error in LoadPetInfo query '%s': %s", query, errbuf);
  		safe_delete_array(query);
          	return;
  	}
+ 	// Unlock the character_pet_inventory table so people can read
+ 	database.RunQuery(query, MakeAnyLenString(&query, "UNLOCK TABLES",errbuf));
+ 	printf(errbuf);
  
  }

[noudess]

Fixed my problem but created other issues for other clients in the same zone....

My unlock is messing with other tables - apparantly no way to unlock just the one table..

Working on a cleaner solution using a mutex.

[noudess]

Ok, this is deeper into the infrastructure than I've messed with.

The idea of locking/unlocking the tables isn't going to work as unlock always releases all tables, and there is other code executing for other clients in the same zone process that locks tables.. So I can't use that method.

A simple mutex is out, as I'm on linux and mutexes don't cross processes without shared memory.

So, I'm guessing a semaphore.. In that case I need to know where all the zone processes are forked, so I can create the semaphore before the zones are forked off.

Or - is there a better way being used already to make sure that 2 zone processes get synbcronized?