In short, add wrappers around Postgres' AddWaitEventToSet() and
ModifyWaitEvent().
AddWaitEventToSet()/ModifyWaitEvent*() may throw hard errors. For
example, when the underlying socket for a connection is closed by
the remote server and already reflected by the OS, however
Citus hasn't had a chance to get this information. In that case,
if replication factor is >1, Citus can failover to other nodes
for executing the query. Even if replication factor = 1, Citus
can give much nicer errors.
So CitusAddWaitEventSetToSet()/CitusModifyWaitEvent() simply puts
AddWaitEventToSet()/ModifyWaitEvent() into a PG_TRY/PG_CATCH block
in order to catch any hard errors, and returns this information to
the caller.
With this commit, we remove visited flags from ForeignConstraintRelationshipNode
struct since keeping local state in global object is both dangerous and
meaningless.
Also to improve readability, this commit also converts needless recursion to
iterative DFS to avoid passing local hash-map as another parameter to
GetConnectedListHelper function.
(cherry picked from commit 0db21bbe14)
This happens only when we have a "<" or "<=" filter on distribution
column of a range distributed table and that filter falls in between
two shards.
When the filter falls in between two shards:
If the filter is ">" or ">=", then UpperShardBoundary was
returning "upperBoundIndex - 1", where upperBoundIndex is
exclusive shard index used during binary seach.
This is expected since upperBoundIndex is an exclusive
index.
If the filter is "<" or "<=", then LowerShardBoundary was
returning "lowerBoundIndex + 1", where lowerBoundIndex is
inclusive shard index used during binary seach.
On the other hand, since lowerBoundIndex is an inclusive
index, we should just return lowerBoundIndex instead of
doing "+ 1". Before this commit, we were missing leftmost
shard in such queries.
* Remove useless conditional branches
The branch that we delete from UpperShardBoundary was obviously useless.
The other one in LowerShardBoundary became useless after we remove "+ 1"
from there.
This indeed is another proof of what & how we are fixing with this pr.
* Improve comments and add more
* Add some tests for upper bound calculation too
(cherry picked from commit b118d4188e)
* Also fix a debug message diff for 9.4
/*
* Colocated intermediate results are just files and not required to use
* the same connections with their co-located shards. So, we are free to
* use any connection we can get.
*
* Also, the current connection re-use logic does not know how to handle
* intermediate results as the intermediate results always truncates the
* existing files. That's why, we use one connection per intermediate
* result.
*/
(cherry picked from commit 5d5a357487)
It looks like we forgot to set the placement accesses, and
this could lead to self-deadlocks on complex transaction blocks.
(cherry picked from commit 36bdeef1bb)
If MemoryContextAlloc errors out -e.g. during an OOM-, ConnectionHashEntry->connections
stays as NULL.
With this commit, we add isValid flag to ConnectionHashEntry that should be set to true
right after we allocate & initialize ConnectionHashEntry->connections list properly, and we
check it before accesing to ConnectionHashEntry->connections.
(cherry picked from commit 7f3d1182ed)
Conflicts:
src/backend/distributed/connection/connection_management.c
It seems that we forgot to pass the revelant
flag to enable Postgres' parallel query
capabilities on the shards when user does
EXPLAIN ANALYZE on a distributed table.
(cherry picked from commit b0ddbbd33a)
Conflicts:
src/backend/distributed/planner/multi_explain.c
Before this commit, we let AdaptiveExecutorPreExecutorRun()
to be effective multiple times on every FETCH on cursors.
That does not affect the correctness of the query results,
but adds significant overhead.
(cherry picked from commit c433c66f2b)
* Not take ShareUpdateExlusiveLock on pg_dist_transaction
We were taking ShareUpdateExlusiveLock on pg_dist_transaction during
recovery to prevent multiple recoveries happening concurrenly. VACUUM(
not FULL) also takes ShareUpdateExclusiveLock, and they can conflict. It
seems that VACUUM will skip the table if there is a conflicting lock
already taken unless it is doing the vacuum to prevent id wraparound, in
which case there can be a deadlock. I guess the deadlock happens if:
- VACUUM takes a lock on pg_dist_transaction and is done for id
wraparound problem
- The transaction in the maintenance tries to take a lock but
cannot as that conflicts with the lock acquired by VACUUM
- The transaction in the maintenance daemon has a very old xid hence
VACUUM cannot proceed.
If we take a row exclusive lock in transaction recovery then it wouldn't
conflict with VACUUM hence it could proceed so the deadlock would be
resolved. To prevent concurrent transaction recoveries happening, an
advisory lock is taken with ShareUpdateExlusiveLock as before.
* Use CITUS_OPERATIONS tag
(cherry picked from commit e7cd1ed0ee)
Conflicts:
src/backend/distributed/transaction/transaction_recovery.c
* Use CalculateUniformHashRangeIndex in HashPartitionId
INT32_MIN definition can change among different platforms hence it is
possible to get overflow, we would see crashes because of this in debian
distros. We have already solved a similar problem with introducing
CalculateUniformHashRangeIndex method, hence to solve it we can use the
same method, this also removes some duplication and has a single place
to decide that.
* Use PG_INT32_XX instead of INT32_XX to be safer
(cherry picked from commit ef841115de)
The reason we should use ActiveReadableNodeList instead of ActiveReadableNonCoordinatorNodeList is that if coordinator is added to cluster as a worker, it should be counted as well. Otherwise if there is only coordinator in the cluster, the count will be 0, hence we get a warning.
In MultiTaskTrackerExecute, we should connect to coordinator if it is
added to the cluster because it will also be assigned tasks.
(cherry picked from commit ae6180ace2931223c58b87444a9e812f5e9f06e8)
ActiveReadableWorkerNodeList doesn't include coordinator, however if
coordinator is added as a worker, we should also include that while
planning. The current methods are very easily misusable and this
requires a refactoring to make the distinction between methods that
include coordinator and that don't very explicit as they can introduce
subtle/major bugs pretty easily.
(cherry picked from commit 86b974e4ceddaf5e2c44799148a8cf485c7d90bf)
Marco Slot
Hanefi Onaldi
Onder Kalaci
naisila
Onur Tirtir
Nils Dijk
Gürkan İndibay
Marco Slot
Önder Kalacı
SaitTalhaNisanci
Halil Ozan Akgul