PG15 introduced an optimization on GROUP BY keys that is now reverted on
RC2.
Relevant PG commit:
Revert "Optimize order of GROUP BY keys".
443df6e2db932a7cd6d85ddfb67e11a43345130d
(cherry picked from commit cbe4298c5b)
Before, this was the default mode for CustomScan providers.
Now, the default is to assume that they can't project.
This causes performance penalties due to adding unnecessary
Result nodes.
Hence we use the newly added flag, CUSTOMPATH_SUPPORT_PROJECTION
to get it back to how it was.
In PG15 support branch we created explain functions to ignore
the new Result nodes, so we undo that in this commit.
Relevant PG commit:
955b3e0f9269639fb916cee3dea37aee50b82df0
* Adjust configure script to allow PG15
* Adds copy of ruleutils_14.c as ruleutils_15.c
* Uses get_namespace_name_or_temp in ruleutils_15.c
Relevant PG commit:
48c5c9068211e0a04fd9553c8714b2821ed3ad17
* Clean up code using "(expr) ? true : false" in ruleutils_15.c
Relevant PG commit:
fd0625c7a9c679c0c1e896014b8f49a489c3a245
* Change varno from Index (unsigned int) to int in ruleutils_15.c
Relevant PG commit:
e3ec3c00d85bd2844ffddee83df2bd67c4f8297f
* Adds find_recursive_union to ruleutils_15.c
Relevant PG commit:
3f50b82639637c9908afa2087de7588450aa866b
* Fix display of SQL-std func's args in INSERT/SELECT in ruleutils_15.c
Relevant PG commit:
a8d8445a7b2f80f6d0bfe97b19f90bd2cbef8759
* Fix ruleutils_15.c's dumping of whole-row Vars in more contexts
Relevant PG commit:
43c2175121c829c8591fc5117b725f1f22bfb670
* Fix assorted missing logic for GroupingFunc nodes in ruleutils_15.c
Relevant PG commit:
2591ee8ec44d8cbc8e1226550337a64c684746e4
* Adds grammar support for SQL/JSON clauses in ruleutils_15.c
Relevant PG commit:
f79b803dcc98d707450e158db3638dc67ff8380b
* Adds SQL/JSON constructors to ruleutils_15.c
Relevant PG commits:
f4fb45d15c59d7add2e1b81a9d477d0119a9691a
cc7401d5ca498a84d9b47fd2e01cebd8e830e558
* Adds support for MERGE in ruleutils_15.c
Relevant PG commit:
7103ebb7aae8ab8076b7e85f335ceb8fe799097c
* Add IS JSON predicate to ruleutils_15.c
Relevant PG commit:
33a377608fc29cdd1f6b63be561eab0aee5c81f0
* Add SQL/JSON query functions to ruleutils_15.c
Relevant PG commit:
1a36bc9dba8eae90963a586d37b6457b32b2fed4
* Adds three different SQL/JSON values to ruleutils_15.c
Relevant PG commits:
606948b058dc16bce494270eea577011a602810e
49082c2cc3d8167cca70cfe697afb064710828ca
* Adds JSON table functions in ruleutils_15.c
Relevant PG commit:
4e34747c88a03ede6e9d731727815e37273d4bc9
* Add PLAN function for JSON table in ruleutils_15.c
Relevant PG commit:
fadb48b00e02ccfd152baa80942de30205ab3c4f
* Remove extra blank lines before block-closing braces ruleutils_15.c
Relevant PG commit:
24d2b2680a8d0e01b30ce8a41c4eb3b47aca5031
* set_deparse_plan: Reuse variable to appease Coverity ruleutils_15.c
Relevant PG commit:
e70813fbc4aaca35ec012d5a426706bd54e4acab
* Mechanical code beautification ruleutils_15.c
Relevant PG commit:
23e7b38bfe396f919fdb66057174d29e17086418
* Rename value_type to item_type in ruleutils_15.c
Relevant PG commit:
3ab9a63cb638a1fd99475668e2da9c237495aeda
* Show 'AS "?column?"' explicitly when it's important in ruleutils_15.c
Relevant PG commit:
c7461fc25558832dd347a9c8150b0f1ed85e36e8
* Fix ruleutils_15.c issues with dropped cols in funcs-returning-composite
Relevant PG commit:
c1d1e8469c77ce6b8e5310955580b4a3eee7fe96
* Change comment regarding functions returning composite in ruleutils_15.c
Relevant PG commit:
c2fa113ddb1117b1f03e91960f65d5d7d8a90270
* Replace int nodes with bool nodes where needed
In PG15, Boolean nodes are added. Pre PG15, internal Boolean values
in Create Role commands were represented by Integer nodes. This
commit replaces int nodes logic with bool nodes logic where needed.
Mostly there are CREATE ROLE logic changes.
Relevant PG commit:
941460fcf731a32e6a90691508d5cfa3d1f8eeaf
* Handle new option colliculocale in CREATE COLLATION logic
In PG15, there is an added option to use ICU as global locale provider.
pg_collation has three locale-related fields: collcollate and collctype,
which are libc-related fields, and a new one colliculocale, which is the
ICU-related field. Only the libc-related fields or the ICU-related field
is set, never both.
Relevant PG commits:
f2553d43060edb210b36c63187d52a632448e1d2
54637508f87bd5f07fb9406bac6b08240283be3b
* Add PG15 tests to CI using test images that have 15beta2 (#6093)
* Change warning message in pg_signal_backend()
Relevant PG commit:
7fa945b857cc1b2964799411f1633468826861ff
* Revert "Add missing ifdef for PG 15"
This reverts commit c7b51025ab.
* Fixes tests for ALTER TRIGGER RENAME consistency for part. tables
Relevant PG commit:
80ba4bb383538a2ee846fece6a7b8da9518b6866
* Prevent creating child triggers on partitions when adding new node
Pre PG15, tgisinternal is true for a "child" trigger on a partition
cloned from the trigger on the parent.
In PG15, tgisinternal is false in that case. However, we don't want to
create this trigger on the partition since it will create a conflict
when we try to attach the partition to the parent table:
ERROR: trigger "..." for relation "{partition_name}" already exists
Relevant PG commit:
f4566345cf40b068368cb5617e61318da60676ec
* Fix tests for generated columns dependency changes
In PG15, For GENERATED columns, all dependencies of the generation
expression are recorded as NORMAL dependencies of the column itself.
This requires CASCADE to drop generated cols with the original col.
PRE PG15, dependencies were recorded as AUTO, with which
generated columns are silently dropped with the original column.
Relevant PG commit:
cb02fcb4c95bae08adaca1202c2081cfc81a28b5
* Explicitly cast catalog "char" column to text before concatenation
Relevant PG commit:
07eee5a0dc642d26f44d65c4e6263304208e8583
* Remove 'AS "?column?"' from test outputs
There were some instances in the following tst outputs
in planning debug outputs where AS "?column?" is added.
We add a normalization rule to remove it as it is not
important.
cte_inline.out
recursive_relation_planning_restriction_pushdown.out
Relevant PG commit:
c7461fc25558832dd347a9c8150b0f1ed85e36e8
* Use pg_backup_stop(PG15) instead of pg_stop_backup(PG<15)
Add an alternative test output because of the change in the
backup modes of Postgres. Specifically here, there is a renaming
issue: pg_stop_backup PRE PG15 vs pg_backup_stop PG15+
The alternative output can be deleted when we drop support for PG14
Relevant PG commit:
39969e2a1e4d7f5a37f3ef37d53bbfe171e7d77a
* Adds citus.mitmfifo GUC
Previously we setting this configuration parameter
in the fly for failure tests schedule.
However, PG15 doesn't allow that anymore: reserved prefixes
like "citus" cannot be used to set non-existing GUCs.
Relevant PG commit:
88103567cb8fa5be46dc9fac3e3b8774951a2be7
* Handles EXPLAIN output diffs in PG15 - Extra result lines
To handle extra "Result" lines in explain outputs, we add explain
method to multi_test_helpers.sql file
- plan_without_result_lines() is added for cases where we want the
whole explain output with only "Result" lines removed
* Handles EXPLAIN output diffs in PG15, Hash Agg/Join leverage
To handle differences in usage of GroupAggregate vs HashAggregate
or Merge Join vs Hash join in cases where this detail doesn't
seem to matter, we use coordinator_plan().
- coordinator_plan() is updated to remove "Result" lines
There are some cases where we have subplans so we add a new
function that prints all Task Count lines as well
- coordinator_plan_with_subplans()
Still not sure of the relevant PG commit
Could be db0d67db2401eb6238ccc04c6407a4fd4f985832
but disabling enable_group_by_reordering didn't help.
* Handles EXPLAIN output diffs in PG15: enable_group_by_reordering
Relevant PG commit
db0d67db2401eb6238ccc04c6407a4fd4f985832
* Normalizes Memory Usage, Buckets, Batches for PG15 explain diffs
We create a new function in multi_test_helpers, which is similar
to explain_merge function in PG15. This explain helper function
normalies Memory Usage, Buckets and Batches, and we use it in the
tests which give a different output for PG15.
* Bump test images to 15beta3 (#6172)
* Omit namespace in post-copy errmsg
Relevant PG commit:
069d33d0c5a021601245e44df77a0423ddd69359
* Handles EXPLAIN output diffs in PG15: extra arrows&result lines
To handle extra "->" arrows resulting from extra Result lines
in explain outputs, we add the following explain method to
multi_test_helpers.sql file
- plan_without_arrows() is added for cases where we want the
whole explain output without arrows and without Result lines
* Alters public schema's owner to pg_database_owner in PG15
In PG15, public schema is owned by pg_database_owner role.
In multi_extension, we drop and recreate the ppublic schema,
hence its owner become the default user in our tests, postgres.
Change that to pg_database_owner for PG15 consistency.
This results in alternative test output for public schema grants
in the following test:
grant_on_schema_propagation.sql
Relevant PG commit: b073c3ccd06e4cb845e121387a43faa8c68a7b62
* Add alternative test outputs for change in Insert Select display
citus_local_tables_queries.sql
coordinator_shouldhaveshards.sql
cte_inline.sql
insert_select_repartition.sql
intermediate_result_pruning.sql
local_shard_execution.sql
local_shard_execution_replicated.sql
multi_deparse_shard_query.sql
multi_insert_select.sql
multi_insert_select_conflict.sql
multi_mx_insert_select_repartition.sql
mx_coordinator_shouldhaveshards.sql
single_node.sql
Relevant PG commit:
a8d8445a7b2f80f6d0bfe97b19f90bd2cbef8759
* Fixes columnar tap tests for PG15
In PG15, Perl test modules have been moved to a new namespace.
Also, postgres node new() and get_new_node() methods have been
unified to one method: new()
We create separate tap tests for PG13/14 and PG15+
and update the Makefiles accordingly.
Relevant PG commits:
201a76183e2056c2217129e12d68c25ec9c559c8
b3b4d8e68ae83f432f43f035c7eb481ef93e1583
* Handles EXPLAIN output diffs in PG15: HashAgg Leverage,alt. output
Still not sure of the relevant PG commit
Could be db0d67db2401eb6238ccc04c6407a4fd4f985832
but disabling enable_group_by_reordering didn't help.
Some refactoring:
Consolidate expression which decides whether GROUP BY/HAVING are pushed down
Rename early pullUpIntermediateRows to hasNonDistributableAggregates
Create WorkerColumnName to handle formatting WORKER_COLUMN_FORMAT
Ignore NULL StringInfo pointers to SafeToPushdownWindowFunction
Fix bug where SubqueryPushdownMultiNodeTree mutates supplied Query,
SafeToPushdownWindowFunction requires the original query as it relies on rtable
Add failing tests, make changes to avoid crashes at least
Fix HAVING subquery pushdown ignoring reference table only subqueries,
also include HAVING in recursive planning
Given that we have a function IsDistributedTable which includes reference tables,
it seems best to have IsDistributedTableRTE & QueryContainsDistributedTableRTE
reflect that they do not include reference tables in their check
Similarly SublinkList's name should reflect that it only scans WHERE
contain_agg_clause asserts that we don't have SubLinks,
use contain_aggs_of_level as suggested by pg sourcecode
DESCRIPTION: Replace the query planner for the coordinator part with the postgres planner
Closes#2761
Citus had a simple rule based planner for the query executed on the query coordinator. This planner grew over time with the addigion of SQL support till it was getting close to the functionality of the postgres planner. Except the code was brittle and its complexity rose which made it hard to add new SQL support.
Given its resemblance with the postgres planner it was a long outstanding wish to replace our hand crafted planner with the well supported postgres planner. This patch replaces our planner with a call to postgres' planner.
Due to the functionality of the postgres planner we needed to support both projections and filters/quals on the citus custom scan node. When a sort operation is planned above the custom scan it might require fields to be reordered in the custom scan before returning the tuple (projection). The postgres planner assumes every custom scan node implements projections. Because we controlled the plan that was created we prevented reordering in the custom scan and never had implemented it before.
A same optimisation applies to having clauses that could have been where clauses. Instead of applying the filter as a having on the aggregate it will push it down into the plan which could reach a custom scan node.
For both filters and projections we have implemented them when tuples are read from the tuple store. If no projections or filters are required it will directly return the tuple from the tuple store. Otherwise it will loop tuples from the tuple store through the filter and projection until a tuple is found and returned.
Besides filters being pushed down a side effect of having quals that could have been a where clause is that a call to read intermediate result could be called before the first tuple is fetched from the custom scan. This failed because the intermediate result would only be pulled to the coordinator on the first tuple fetch. To overcome this problem we do run the distributed subplans now before we run the postgres executor. This ensures the intermediate result is present on the coordinator in time. We do account for total time instrumentation by removing the instrumentation before handing control to the psotgres executor and update the timings our self.
For future SQL support it is enough to create a valid query structure for the part of the query to be executed on the query coordinating node. As a utility we do serialise and print the query at debug level4 for engineers to inspect what kind of query is being planned on the query coordinator.
Areas for further optimization:
- Don't save subquery results to a local file on the coordinator when the subquery is not in the having clause
- Push the the HAVING with subquery to the workers if there's a group by on the distribution column
- Don't push down the results to the workers when we don't push down the HAVING clause, only the coordinator needs it
Fixes#520Fixes#756Closes#2047
With this commit, we're introducing the Adaptive Executor.
The commit message consists of two distinct sections. The first part explains
how the executor works. The second part consists of the commit messages of
the individual smaller commits that resulted in this commit. The readers
can search for the each of the smaller commit messages on
https://github.com/citusdata/citus and can learn more about the history
of the change.
/*-------------------------------------------------------------------------
*
* adaptive_executor.c
*
* The adaptive executor executes a list of tasks (queries on shards) over
* a connection pool per worker node. The results of the queries, if any,
* are written to a tuple store.
*
* The concepts in the executor are modelled in a set of structs:
*
* - DistributedExecution:
* Execution of a Task list over a set of WorkerPools.
* - WorkerPool
* Pool of WorkerSessions for the same worker which opportunistically
* executes "unassigned" tasks from a queue.
* - WorkerSession:
* Connection to a worker that is used to execute "assigned" tasks
* from a queue and may execute unasssigned tasks from the WorkerPool.
* - ShardCommandExecution:
* Execution of a Task across a list of placements.
* - TaskPlacementExecution:
* Execution of a Task on a specific placement.
* Used in the WorkerPool and WorkerSession queues.
*
* Every connection pool (WorkerPool) and every connection (WorkerSession)
* have a queue of tasks that are ready to execute (readyTaskQueue) and a
* queue/set of pending tasks that may become ready later in the execution
* (pendingTaskQueue). The tasks are wrapped in a ShardCommandExecution,
* which keeps track of the state of execution and is referenced from a
* TaskPlacementExecution, which is the data structure that is actually
* added to the queues and describes the state of the execution of a task
* on a particular worker node.
*
* When the task list is part of a bigger distributed transaction, the
* shards that are accessed or modified by the task may have already been
* accessed earlier in the transaction. We need to make sure we use the
* same connection since it may hold relevant locks or have uncommitted
* writes. In that case we "assign" the task to a connection by adding
* it to the task queue of specific connection (in
* AssignTasksToConnections). Otherwise we consider the task unassigned
* and add it to the task queue of a worker pool, which means that it
* can be executed over any connection in the pool.
*
* A task may be executed on multiple placements in case of a reference
* table or a replicated distributed table. Depending on the type of
* task, it may not be ready to be executed on a worker node immediately.
* For instance, INSERTs on a reference table are executed serially across
* placements to avoid deadlocks when concurrent INSERTs take conflicting
* locks. At the beginning, only the "first" placement is ready to execute
* and therefore added to the readyTaskQueue in the pool or connection.
* The remaining placements are added to the pendingTaskQueue. Once
* execution on the first placement is done the second placement moves
* from pendingTaskQueue to readyTaskQueue. The same approach is used to
* fail over read-only tasks to another placement.
*
* Once all the tasks are added to a queue, the main loop in
* RunDistributedExecution repeatedly does the following:
*
* For each pool:
* - ManageWorkPool evaluates whether to open additional connections
* based on the number unassigned tasks that are ready to execute
* and the targetPoolSize of the execution.
*
* Poll all connections:
* - We use a WaitEventSet that contains all (non-failed) connections
* and is rebuilt whenever the set of active connections or any of
* their wait flags change.
*
* We almost always check for WL_SOCKET_READABLE because a session
* can emit notices at any time during execution, but it will only
* wake up WaitEventSetWait when there are actual bytes to read.
*
* We check for WL_SOCKET_WRITEABLE just after sending bytes in case
* there is not enough space in the TCP buffer. Since a socket is
* almost always writable we also use WL_SOCKET_WRITEABLE as a
* mechanism to wake up WaitEventSetWait for non-I/O events, e.g.
* when a task moves from pending to ready.
*
* For each connection that is ready:
* - ConnectionStateMachine handles connection establishment and failure
* as well as command execution via TransactionStateMachine.
*
* When a connection is ready to execute a new task, it first checks its
* own readyTaskQueue and otherwise takes a task from the worker pool's
* readyTaskQueue (on a first-come-first-serve basis).
*
* In cases where the tasks finish quickly (e.g. <1ms), a single
* connection will often be sufficient to finish all tasks. It is
* therefore not necessary that all connections are established
* successfully or open a transaction (which may be blocked by an
* intermediate pgbouncer in transaction pooling mode). It is therefore
* essential that we take a task from the queue only after opening a
* transaction block.
*
* When a command on a worker finishes or the connection is lost, we call
* PlacementExecutionDone, which then updates the state of the task
* based on whether we need to run it on other placements. When a
* connection fails or all connections to a worker fail, we also call
* PlacementExecutionDone for all queued tasks to try the next placement
* and, if necessary, mark shard placements as inactive. If a task fails
* to execute on all placements, the execution fails and the distributed
* transaction rolls back.
*
* For multi-row INSERTs, tasks are executed sequentially by
* SequentialRunDistributedExecution instead of in parallel, which allows
* a high degree of concurrency without high risk of deadlocks.
* Conversely, multi-row UPDATE/DELETE/DDL commands take aggressive locks
* which forbids concurrency, but allows parallelism without high risk
* of deadlocks. Note that this is unrelated to SEQUENTIAL_CONNECTION,
* which indicates that we should use at most one connection per node, but
* can run tasks in parallel across nodes. This is used when there are
* writes to a reference table that has foreign keys from a distributed
* table.
*
* Execution finishes when all tasks are done, the query errors out, or
* the user cancels the query.
*
*-------------------------------------------------------------------------
*/
All the commits involved here:
* Initial unified executor prototype
* Latest changes
* Fix rebase conflicts to master branch
* Add missing variable for assertion
* Ensure that master_modify_multiple_shards() returns the affectedTupleCount
* Adjust intermediate result sizes
The real-time executor uses COPY command to get the results
from the worker nodes. Unified executor avoids that which
results in less data transfer. Simply adjust the tests to lower
sizes.
* Force one connection per placement (or co-located placements) when requested
The existing executors (real-time and router) always open 1 connection per
placement when parallel execution is requested.
That might be useful under certain circumstances:
(a) User wants to utilize as much as CPUs on the workers per
distributed query
(b) User has a transaction block which involves COPY command
Also, lots of regression tests rely on this execution semantics.
So, we'd enable few of the tests with this change as well.
* For parameters to be resolved before using them
For the details, see PostgreSQL's copyParamList()
* Unified executor sorts the returning output
* Ensure that unified executor doesn't ignore sequential execution of DDLJob's
Certain DDL commands, mainly creating foreign keys to reference tables,
should be executed sequentially. Otherwise, we'd end up with a self
distributed deadlock.
To overcome this situaiton, we set a flag `DDLJob->executeSequentially`
and execute it sequentially. Note that we have to do this because
the command might not be called within a transaction block, and
we cannot call `SetLocalMultiShardModifyModeToSequential()`.
This fixes at least two test: multi_insert_select_on_conflit.sql and
multi_foreign_key.sql
Also, I wouldn't mind scattering local `targetPoolSize` variables within
the code. The reason is that we'll soon have a GUC (or a global
variable based on a GUC) that'd set the pool size. In that case, we'd
simply replace `targetPoolSize` with the global variables.
* Fix 2PC conditions for DDL tasks
* Improve closing connections that are not fully established in unified execution
* Support foreign keys to reference tables in unified executor
The idea for supporting foreign keys to reference tables is simple:
Keep track of the relation accesses within a transaction block.
- If a parallel access happens on a distributed table which
has a foreign key to a reference table, one cannot modify
the reference table in the same transaction. Otherwise,
we're very likely to end-up with a self-distributed deadlock.
- If an access to a reference table happens, and then a parallel
access to a distributed table (which has a fkey to the reference
table) happens, we switch to sequential mode.
Unified executor misses the function calls that marks the relation
accesses during the execution. Thus, simply add the necessary calls
and let the logic kick in.
* Make sure to close the failed connections after the execution
* Improve comments
* Fix savepoints in unified executor.
* Rebuild the WaitEventSet only when necessary
* Unclaim connections on all errors.
* Improve failure handling for unified executor
- Implement the notion of errorOnAnyFailure. This is similar to
Critical Connections that the connection managament APIs provide
- If the nodes inside a modifying transaction expand, activate 2PC
- Fix few bugs related to wait event sets
- Mark placement INACTIVE during the execution as much as possible
as opposed to we do in the COMMIT handler
- Fix few bugs related to scheduling next placement executions
- Improve decision on when to use 2PC
Improve the logic to start a transaction block for distributed transactions
- Make sure that only reference table modifications are always
executed with distributed transactions
- Make sure that stored procedures and functions are executed
with distributed transactions
* Move waitEventSet to DistributedExecution
This could also be local to RunDistributedExecution(), but in that case
we had to mark it as "volatile" to avoid PG_TRY()/PG_CATCH() issues, and
cast it to non-volatile when doing WaitEventSetFree(). We thought that
would make code a bit harder to read than making this non-local, so we
move it here. See comments for PG_TRY() in postgres/src/include/elog.h
and "man 3 siglongjmp" for more context.
* Fix multi_insert_select test outputs
Two things:
1) One complex transaction block is now supported. Simply update
the test output
2) Due to dynamic nature of the unified executor, the orders of
the errors coming from the shards might change (e.g., all of
the queries on the shards would fail, but which one appears
on the error message?). To fix that, we simply added it to
our shardId normalization tool which happens just before diff.
* Fix subeury_and_cte test
The error message is updated from:
failed to execute task
To:
more than one row returned by a subquery or an expression
which is a lot clearer to the user.
* Fix intermediate_results test outputs
Simply update the error message from:
could not receive query results
to
result "squares" does not exist
which makes a lot more sense.
* Fix multi_function_in_join test
The error messages update from:
Failed to execute task XXX
To:
function f(..) does not exist
* Fix multi_query_directory_cleanup test
The unified executor does not create any intermediate files.
* Fix with_transactions test
A test case that just started to work fine
* Fix multi_router_planner test outputs
The error message is update from:
Could not receive query results
To:
Relation does not exists
which is a lot more clearer for the users
* Fix multi_router_planner_fast_path test
The error message is update from:
Could not receive query results
To:
Relation does not exists
which is a lot more clearer for the users
* Fix isolation_copy_placement_vs_modification by disabling select_opens_transaction_block
* Fix ordering in isolation_multi_shard_modify_vs_all
* Add executor locks to unified executor
* Make sure to allocate enought WaitEvents
The previous code was missing the waitEvents for the latch and
postmaster death.
* Fix rebase conflicts for master rebase
* Make sure that TRUNCATE relies on unified executor
* Implement true sequential execution for multi-row INSERTS
Execute the individual tasks executed one by one. Note that this is different than
MultiShardConnectionType == SEQUENTIAL_CONNECTION case (e.g., sequential execution
mode). In that case, running the tasks across the nodes in parallel is acceptable
and implemented in that way.
However, the executions that are qualified here would perform poorly if the
tasks across the workers are executed in parallel. We currently qualify only
one class of distributed queries here, multi-row INSERTs. If we do not enforce
true sequential execution, concurrent multi-row upserts could easily form
a distributed deadlock when the upserts touch the same rows.
* Remove SESSION_LIFESPAN flag in unified_executor
* Apply failure test updates
We've changed the failure behaviour a bit, and also the error messages
that show up to the user. This PR covers majority of the updates.
* Unified executor honors citus.node_connection_timeout
With this commit, unified executor errors out if even
a single connection cannot be established within
citus.node_connection_timeout.
And, as a side effect this fixes failure_connection_establishment
test.
* Properly increment/decrement pool size variables
Before this commit, the idle and active connection
counts were not properly calculated.
* insert_select_executor goes through unified executor.
* Add missing file for task tracker
* Modify ExecuteTaskListExtended()'s signature
* Sort output of INSERT ... SELECT ... RETURNING
* Take partition locks correctly in unified executor
* Alternative implementation for force_max_query_parallelization
* Fix compile warnings in unified executor
* Fix style issues
* Decrement idleConnectionCount when idle connection is lost
* Always rebuild the wait event sets
In the previous implementation, on waitFlag changes, we were only
modifying the wait events. However, we've realized that it might
be an over optimization since (a) we couldn't see any performance
benefits (b) we see some errors on failures and because of (a)
we prefer to disable it now.
* Make sure to allocate enough sized waitEventSet
With multi-row INSERTs, we might have more sessions than
task*workerCount after few calls of RunDistributedExecution()
because the previous sessions would also be alive.
Instead, re-allocate events when the connectino set changes.
* Implement SELECT FOR UPDATE on reference tables
On master branch, we do two extra things on SELECT FOR UPDATE
queries on reference tables:
- Acquire executor locks
- Execute the query on all replicas
With this commit, we're implementing the same logic on the
new executor.
* SELECT FOR UPDATE opens transaction block even if SelectOpensTransactionBlock disabled
Otherwise, users would be very confused and their logic is very likely
to break.
* Fix build error
* Fix the newConnectionCount calculation in ManageWorkerPool
* Fix rebase conflicts
* Fix minor test output differences
* Fix citus indent
* Remove duplicate sorts that is added with rebase
* Create distributed table via executor
* Fix wait flags in CheckConnectionReady
* failure_savepoints output for unified executor.
* failure_vacuum output (pg 10) for unified executor.
* Fix WaitEventSetWait timeout in unified executor
* Stabilize failure_truncate test output
* Add an ORDER BY to multi_upsert
* Fix regression test outputs after rebase to master
* Add executor.c comment
* Rename executor.c to adaptive_executor.c
* Do not schedule tasks if the failed placement is not ready to execute
Before the commit, we were blindly scheduling the next placement executions
even if the failed placement is not on the ready queue. Now, we're ensuring
that if failed placement execution is on a failed pool or session where the
execution is on the pendingQueue, we do not schedule the next task. Because
the other placement execution should be already running.
* Implement a proper custom scan node for adaptive executor
- Switch between the executors, add GUC to set the pool size
- Add non-adaptive regression test suites
- Enable CIRCLE CI for non-adaptive tests
- Adjust test output files
* Add slow start interval to the executor
* Expose max_cached_connection_per_worker to user
* Do not start slow when there are cached connections
* Consider ExecutorSlowStartInterval in NextEventTimeout
* Fix memory issues with ReceiveResults().
* Disable executor via TaskExecutorType
* Make sure to execute the tests with the other executor
* Use task_executor_type to enable-disable adaptive executor
* Remove useless code
* Adjust the regression tests
* Add slow start regression test
* Rebase to master
* Fix test failures in adaptive executor.
* Rebase to master - 2
* Improve comments & debug messages
* Set force_max_query_parallelization in isolation_citus_dist_activity
* Force max parallelization for creating shards when asked to use exclusive connection.
* Adjust the default pool size
* Expand description of max_adaptive_executor_pool_size GUC
* Update warnings in FinishRemoteTransactionCommit()
* Improve session clean up at the end of execution
Explicitly list all the states that the execution might end,
otherwise warn.
* Remove MULTI_CONNECTION_WAIT_RETRY which is not used at all
* Add more ORDER BYs to multi_mx_partitioning
After this commit large_table_shard_count wont be used to
check whether broadcast join, which is renamed as reference
join, can be applied. Reference join can only be applied over
reference tables.
Pushing down limit and order by into workers may produce
wrong output when distinct on() clause has expressions,
aggregates, or window functions.
This checking allows pushing down of limits only if
distinct clause is a superset of group by clause. i.e. it contains all clauses in group by.
We push down order by to worker query when limit is specified
(with some other additional checks). If the query has an expression
on an aggregate or avg aggregate by itself, and there is an order
by on this particular target we may send wrong order by to worker
query with potential to affect query result.
The fix creates a auxilary target entry in the worker query and
uses that target entry for sorting.
Before this PR, we were trusting on the columns of group by about
guaranteeing the uniqueness of the results. However, this assumption
is correct only if the columns in the group by is subset of columns
in the distinct clause. It can be wrong if we have part of group by
columns and some aggregation columns in the distinct clause. With
this PR, we add distinct plan on top of aggregate plan when necessary.
Hanefi Onaldi
Naisila Puka
Sait Talha Nisanci
Philip Dubé
Nils Dijk
Jelte Fennema
Marco Slot
Philip Dubé
Önder Kalacı
Hadi Moshayedi
velioglu
Murat Tuncer
metdos
mehmet furkan şahin
Murat Tuncer