external
/
citus
mirror of https://github.com/citusdata/citus.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Keep track of cached entries in case of interruption. (#2433) 

* Keep track of cached entries in case of interruption.

Previously we set DistTableCacheEntry->sortedShardIntervalArray
and DistTableCacheEntry->shardIntervalArrayLength after we entered
all related shard entries into DistShardCacheHash. The drawback was
that if populating DistShardCacheHash was interrupted,
ResetDistTableCacheEntry() didn't see the shard hash entries created,
so was unable to clean them up.

This patch fixes that by setting sortedShardIntervalArray earlier,
and incrementing shardIntervalArrayLength as we enter shards into
the cache.
pull/2436/head
Hadi Moshayedi 2018-10-15 14:06:56 -04:00 committed by GitHub
parent a9f183a284
commit 431ac80563
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 28 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

31
src/backend/distributed/utils/metadata_cache.c
View File

@ -860,12 +860,22 @@ LookupDistTableCacheEntry(Oid relationId)
memset(((char *) cacheEntry) + sizeof(Oid), 0,
sizeof(DistTableCacheEntry) - sizeof(Oid));
/*
* We disable interrupts while creating the cache entry because loading
* shard metadata can take a while, and if statement_timeout is too low,
* this will get canceled on each call and we won't be able to run any
* queries on the table.
*/
HOLD_INTERRUPTS();
/* actually fill out entry */
BuildDistTableCacheEntry(cacheEntry);
/* and finally mark as valid */
cacheEntry->isValid = true;
RESUME_INTERRUPTS();
return cacheEntry;
}
@ -1170,6 +1180,13 @@ BuildCachedShardList(DistTableCacheEntry *cacheEntry)
}
}
/*
* We set these here, so ResetDistTableCacheEntry() can see what has been
* entered into DistShardCacheHash even if the following loop is interrupted
* by throwing errors, etc.
*/
cacheEntry->sortedShardIntervalArray = sortedShardIntervalArray;
cacheEntry->shardIntervalArrayLength = 0;
/* maintain shardId->(table,ShardInterval) cache */
for (shardIndex = 0; shardIndex < shardIntervalArrayLength; shardIndex++)
@ -1194,6 +1211,13 @@ BuildCachedShardList(DistTableCacheEntry *cacheEntry)
errhint("Reconnect and try again.")));
}
/*
* We should increment this only after we are sure this hasn't already
* been assigned to any other relations. ResetDistTableCacheEntry()
* depends on this.
*/
cacheEntry->shardIntervalArrayLength++;
shardEntry->shardIndex = shardIndex;
shardEntry->tableEntry = cacheEntry;
@ -1222,8 +1246,6 @@ BuildCachedShardList(DistTableCacheEntry *cacheEntry)
shardInterval->shardIndex = shardIndex;
}
cacheEntry->shardIntervalArrayLength = shardIntervalArrayLength;
cacheEntry->sortedShardIntervalArray = sortedShardIntervalArray;
cacheEntry->shardColumnCompareFunction = shardColumnCompareFunction;
cacheEntry->shardIntervalCompareFunction = shardIntervalCompareFunction;
}
@ -2934,7 +2956,10 @@ ResetDistTableCacheEntry(DistTableCacheEntry *cacheEntry)
bool foundInCache = false;
/* delete the shard's placements */
pfree(placementArray);
if (placementArray != NULL)
{
pfree(placementArray);
}
/* delete per-shard cache-entry */
hash_search(DistShardCacheHash, &shardInterval->shardId, HASH_REMOVE,