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Harden ReplicateShardToNode to unexpected placements (#5071) 

Originally ReplicateShardToNode was meant for
`upgrade_to_reference_table`, which required handling of existing inactive
placements. These days `upgrade_to_reference_table` is deprecated and
cannot be used anymore. Now that we have SHARD_STATE_TO_DELETE too, this
left over code seemed error prone. So this removes support for
activating inactive reference table placemements, since these should not
be possible. If it finds a non active reference table placement anyway
it now errors out.

This also removes a few outdated comments related to `upgrade_to_refeference_table`.
pull/5073/head^2
Jelte Fennema 2021-06-24 12:11:02 +02:00 committed by GitHub
parent d1d386a904
commit f4a2d99ce9
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1 changed files with 34 additions and 46 deletions
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80
src/backend/distributed/utils/reference_table_utils.c
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@ -327,9 +327,12 @@ upgrade_to_reference_table(PG_FUNCTION_ARGS)
/* /*
* ReplicateShardToNode function replicates given shard to the given worker node * ReplicateShardToNode function replicates given shard to the given worker node
* in a separate transaction. While replicating, it only replicates the shard to the * in a separate transaction. If the worker already has
* workers which does not have a healthy replica of the shard. This function also modifies * a replica of the shard this is a no-op. This function also modifies metadata
* metadata by inserting/updating related rows in pg_dist_placement. * by inserting/updating related rows in pg_dist_placement.
*
* IMPORTANT: This should only be used to replicate shards of a reference
* table.
*/ */
static void static void
ReplicateShardToNode(ShardInterval *shardInterval, char *nodeName, int nodePort) ReplicateShardToNode(ShardInterval *shardInterval, char *nodeName, int nodePort)
@ -349,54 +352,39 @@ ReplicateShardToNode(ShardInterval *shardInterval, char *nodeName, int nodePort)
nodeName, nodePort); nodeName, nodePort);
char *tableOwner = TableOwner(shardInterval->relationId); char *tableOwner = TableOwner(shardInterval->relationId);
/* if (targetPlacement != NULL)
* Although this function is used for reference tables, and reference table shard
* placements always have shardState = SHARD_STATE_ACTIVE, in case of an upgrade
* of a non-reference table to reference table, unhealty placements may exist.
* In this case, repair the shard placement and update its state in pg_dist_placement.
*/
if (targetPlacement == NULL || targetPlacement->shardState != SHARD_STATE_ACTIVE)
{ {
uint64 placementId = 0; if (targetPlacement->shardState == SHARD_STATE_ACTIVE)
int32 groupId = 0;
ereport(NOTICE, (errmsg("Replicating reference table \"%s\" to the node %s:%d",
get_rel_name(shardInterval->relationId), nodeName,
nodePort)));
EnsureNoModificationsHaveBeenDone();
SendCommandListToWorkerInSingleTransaction(nodeName, nodePort, tableOwner,
ddlCommandList);
if (targetPlacement == NULL)
{ {
groupId = GroupForNode(nodeName, nodePort); /* We already have the shard, nothing to do */
return;
placementId = GetNextPlacementId();
InsertShardPlacementRow(shardId, placementId, SHARD_STATE_ACTIVE, 0,
groupId);
}
else
{
groupId = targetPlacement->groupId;
placementId = targetPlacement->placementId;
UpdateShardPlacementState(placementId, SHARD_STATE_ACTIVE);
} }
ereport(ERROR, (errmsg(
"Placement for reference table \"%s\" on node %s:%d is not active. This should not be possible, please report this as a bug",
get_rel_name(shardInterval->relationId), nodeName,
nodePort)));
}
/* ereport(NOTICE, (errmsg("Replicating reference table \"%s\" to the node %s:%d",
* Although ReplicateShardToAllNodes is used only for reference tables, get_rel_name(shardInterval->relationId), nodeName,
* during the upgrade phase, the placements are created before the table is nodePort)));
* marked as a reference table. All metadata (including the placement
* metadata) will be copied to workers after all reference table changed
* are finished.
*/
if (ShouldSyncTableMetadata(shardInterval->relationId))
{
char *placementCommand = PlacementUpsertCommand(shardId, placementId,
SHARD_STATE_ACTIVE, 0,
groupId);
SendCommandToWorkersWithMetadata(placementCommand); EnsureNoModificationsHaveBeenDone();
} SendCommandListToWorkerInSingleTransaction(nodeName, nodePort, tableOwner,
ddlCommandList);
int32 groupId = GroupForNode(nodeName, nodePort);
uint64 placementId = GetNextPlacementId();
InsertShardPlacementRow(shardId, placementId, SHARD_STATE_ACTIVE, 0,
groupId);
if (ShouldSyncTableMetadata(shardInterval->relationId))
{
char *placementCommand = PlacementUpsertCommand(shardId, placementId,
SHARD_STATE_ACTIVE, 0,
groupId);
SendCommandToWorkersWithMetadata(placementCommand);
} }
} }