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Sync metadata in new clusters 

If a user upgrades from an ealier version, and have not synced the
metadata, we should not automatically sync the metadata.

If this is a post Citus 11 cluster, and we are adding a new worker node,
we sync the metadata.

The net effect is that new clusters gets Citus MX by default, existing
clusters should manually trigger metadata syncing.
sync_metadata_only_needed
Onder Kalaci 2021-12-21 09:28:38 +01:00
parent 80f41e94c0
commit ee472e789e
2 changed files with 35 additions and 6 deletions
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39
src/backend/distributed/metadata/node_metadata.c
View File

@ -91,6 +91,7 @@ typedef struct NodeMetadata
/* local function forward declarations */
static int ActivateNode(char *nodeName, int nodePort);
static bool ShouldSyncMetadataToNewNode(WorkerNode *newNode);
static void RemoveNodeFromCluster(char *nodeName, int32 nodePort);
static void ErrorIfNodeContainsNonRemovablePlacements(WorkerNode *workerNode);
static bool PlacementHasActivePlacementOnAnotherGroup(GroupShardPlacement
@ -883,8 +884,7 @@ ActivateNode(char *nodeName, int nodePort)
workerNode =
SetWorkerColumnLocalOnly(workerNode, Anum_pg_dist_node_isactive,
BoolGetDatum(isActive));
bool syncMetadata =
EnableMetadataSyncByDefault && NodeIsPrimary(workerNode);
bool syncMetadata = ShouldSyncMetadataToNewNode(workerNode);
if (syncMetadata)
{
@ -911,6 +911,35 @@ ActivateNode(char *nodeName, int nodePort)
}
/*
* ShouldSyncMetadataToNewNode decides to sync metadata to new node only if
* there is at least one healthy primary worker node with metadata synced.
*
* This is to prevent upgrades from pre Citus-11 to post Citus-11 to automatically
* convert the cluster to a metadata synced cluster. However, if the cluster is
* post Citus-11 (or had 0 workers on pre Citus-11), we'd sync the metadata.
*/
static bool
ShouldSyncMetadataToNewNode(WorkerNode *newNode)
{
uint32 primaryWorkerCount = ActivePrimaryNonCoordinatorNodeCount();
uint32 primariesWithMetadata = CountPrimaryWorkersWithMetadata();
if (primaryWorkerCount != 0 && primariesWithMetadata == 0)
{
/*
* This cluster doesnt't have any worker nodes with
* metadata synced. In these cases, we refrain from
* syncing the metadata.
*/
return false;
}
/* otherwise, we check if the user explicitly disabled metadata syncing */
return EnableMetadataSyncByDefault && NodeIsPrimary(newNode);
}
/*
* citus_update_node moves the requested node to a different nodename and nodeport. It
* locks to ensure no queries are running concurrently; and is intended for customers who
@ -1472,9 +1501,9 @@ RemoveOldShardPlacementForNodeGroup(int groupId)
}
/* CountPrimariesWithMetadata returns the number of primary nodes which have metadata. */
/* CountPrimaryWorkersWithMetadata returns the number of primary nodes which have metadata. */
uint32
CountPrimariesWithMetadata(void)
CountPrimaryWorkersWithMetadata(void)
{
uint32 primariesWithMetadata = 0;
WorkerNode *workerNode = NULL;
@ -1648,7 +1677,7 @@ AddNodeMetadata(char *nodeName, int32 nodePort,
SendCommandToWorkersWithMetadata(nodeDeleteCommand);
/* finally prepare the insert command and send it to all primary nodes */
uint32 primariesWithMetadata = CountPrimariesWithMetadata();
uint32 primariesWithMetadata = CountPrimaryWorkersWithMetadata();
if (primariesWithMetadata != 0)
{
List *workerNodeList = list_make1(workerNode);

2
src/include/distributed/worker_manager.h
View File

@ -101,7 +101,7 @@ extern WorkerNode * SetWorkerColumnOptional(WorkerNode *workerNode, int columnIn
value);
extern WorkerNode * SetWorkerColumnLocalOnly(WorkerNode *workerNode, int columnIndex,
Datum value);
extern uint32 CountPrimariesWithMetadata(void);
extern uint32 CountPrimaryWorkersWithMetadata(void);
extern WorkerNode * GetFirstPrimaryWorkerNode(void);
/* Function declarations for worker node utilities */