Commit Graph

163 Commits (d11f6eb4ddd6c5ece361fb915d175d12628f3905)

Author SHA1 Message Date
Philip Dubé 3a906b8210 Fix typos noticed while reading through code trying to understand HAVING 2020-02-11 19:55:10 +00:00
Onder Kalaci c7e2309f4c Improve single hash-repartitioning with numeric (or non-int) types
We used to treat the shard interval array that we passed as numeric[].
However, it should be int[], as the shard ranges are int[].
2020-02-04 20:30:04 +01:00
Jelte Fennema 246435be7e
Lazy query deparsing executable queries (#3350)
Deparsing and parsing a query can be heavy on CPU. When locally executing 
the query we don't need to do this in theory most of the time.

This PR is the first step in allowing to skip deparsing and parsing
the query in these cases, by lazily creating the query string and
storing the query in the task. Future commits will make use of this and
not deparse and parse the query anymore, but use the one from the task
directly.
2020-01-17 11:49:43 +01:00
Philip Dubé 4b5d6c3ebe Rename RelayFileState to ShardState
Replace FILE_ prefix with SHARD_STATE_
2020-01-12 05:57:53 +00:00
Philip Dubé e71386af33 Replace ARRAY_OUT_FUNC_ID with postgres's F_ARRAY_OUT
Also use stack allocation for walkerContext in multi_logical_optimizer
2020-01-10 16:54:00 +00:00
Philip Dubé 281aacce9b Fix row-gather for subqueries being handled by task-tracker
task-tracker has specific logic for MultiPartition when GROUP BY is missing

We were ending up in this code path because row-gather removes GROUP BY
2020-01-10 01:51:37 +00:00
Hadi Moshayedi f38d0e5b3f Partitioned task list results. 2020-01-09 10:32:58 -08:00
Jelte Fennema 3a042e4611 Allow cartesian products on reference tables 2019-12-27 15:05:51 +01:00
Jelte Fennema 61e2501645 Make any expression with two or more tables a join expression 2019-12-27 15:05:51 +01:00
Marco Slot b37ef0e394 Fix error in distributed queries when shards are on the coordinator 2019-12-24 06:36:43 +01:00
SaitTalhaNisanci 7ff4ce2169
Add adaptive executor support for repartition joins (#3169)
* WIP

* wip

* add basic logic to run a single job with repartioning joins with adaptive executor

* fix some warnings and return in ExecuteDependedTasks if there is none

* Add the logic to run depended jobs in adaptive executor

The execution of depended tasks logic is changed. With the current
logic:
- All tasks are created from the top level task list.
- At one iteration:
	- CurTasks whose dependencies are executed are found.
	- CurTasks are executed in parallel with adapter executor main
logic.
- The iteration is repeated until all tasks are completed.

* Separate adaptive executor repartioning logic

* Remove duplicate parts

* cleanup directories and schemas

* add basic repartion tests for adaptive executor

* Use the first placement to fetch data

In task tracker, when there are replicas, we try to fetch from a replica
for which a map task is succeeded. TaskExecution is used for this,
however TaskExecution is not used in adaptive executor. So we cannot use
the same thing as task tracker.

Since adaptive executor fails when a map task fails (There is no retry
logic yet). We know that if we try to execute a fetch task, all of its
map tasks already succeeded, so we can just use the first one to fetch
from.

* fix clean directories logic

* do not change the search path while creating a udf

* Enable repartition joins with adaptive executor with only enable_reparitition_joins guc

* Add comments to adaptive_executor_repartition

* dont run adaptive executor repartition test in paralle with other tests

* execute cleanup only in the top level execution

* do cleanup only in the top level ezecution

* not begin a transaction if repartition query is used

* use new connections for repartititon specific queries

New connections are opened to send repartition specific queries. The
opened connections will be closed at the FinishDistributedExecution.

While sending repartition queries no transaction is begun so that
we can see all changes.

* error if a modification was done prior to repartition execution

* not start a transaction if a repartition query and sql task, and clean temporary files and schemas at each subplan level

* fix cleanup logic

* update tests

* add missing function comments

* add test for transaction with DDL before repartition query

* do not close repartition connections in adaptive executor

* rollback instead of commit in repartition join test

* use close connection instead of shutdown connection

* remove unnecesary connection list, ensure schema owner before removing directory

* rename ExecuteTaskListRepartition

* put fetch query string in planner not executor as we currently support only replication factor = 1 with adaptive executor and repartition query and we know the query string in the planner phase in that case

* split adaptive executor repartition to DAG execution logic and repartition logic

* apply review items

* apply review items

* use an enum for remote transaction state and fix cleanup for repartition

* add outside transaction flag to find connections that are unclaimed instead of always opening a new transaction

* fix style

* wip

* rename removejobdir to partition cleanup

* do not close connections at the end of repartition queries

* do repartition cleanup in pg catch

* apply review items

* decide whether to use transaction or not at execution creation

* rename isOutsideTransaction and add missing comment

* not error in pg catch while doing cleanup

* use replication factor of the creation time, not current time to decide if task tracker should be chosen

* apply review items

* apply review items

* apply review item
2019-12-17 19:09:45 +03:00
SaitTalhaNisanci a2f2107e6a
refactor MapTaskList in multi physical planner (#3297) 2019-12-13 22:41:49 +03:00
Marco Slot e7a8db5493 Fix issue with some zero-shard modifications 2019-12-12 07:19:10 +01:00
Philip Dubé fcf2fd819b Add distributioncolumncollation to to pg_dist_colocation
Use partition column's collation for range distributed tables
Don't allow non deterministic collations for hash distributed tables
CoPartitionedTables: don't compare unequal types
2019-12-09 19:51:40 +00:00
Philip Dubé 5fcc169a3a Stray depended to dependent tidy up 2019-12-03 15:28:32 +00:00
Marco Slot 16d1ad3666 Remove distinction between SQL_TASK and ROUTER_TASK 2019-11-29 05:58:29 +01:00
SaitTalhaNisanci aeec3d1544
fix typo in dependent jobs and dependent task (#3244) 2019-11-28 23:47:28 +03:00
Jelte Fennema 1d8dde232f
Automatically convert useless declarations using regex replace (#3181)
* Add declaration removal to CI

* Convert declarations
2019-11-21 13:47:29 +01:00
Nils Dijk 217890af5f
Feature: Expression in reference join (#3180)
DESCRIPTION: Expression in reference join

Fixed: #2582

This patch allows arbitrary expressions in the join clause when joining to a reference table. An example of such joins could be found in CHbenCHmark queries 7, 8, 9 and 11; `mod((s_w_id * s_i_id),10000) = su_suppkey` and `ascii(substr(c_state,1,1)) = n2.n_nationkey`. Since the join is on a reference table these queries are able to be pushed down to the workers.

To implement these queries we will widen the `IsJoinClause` predicate to not check if the expressions are a type `Var` after stripping the implicit coerciens. Instead we define a join clause when the `Var`'s in a clause come from more than 1 table.

This allows more clauses to pass into the logical planner's `MultiNodeTree(...)` planning function. To compensate for this we tighten down the `LocalJoin`, `SinglePartitionJoin` and `DualPartitionJoin` to check for direct column references when planning. This allows the planner to work with arbitrary join expressions on reference tables.
2019-11-18 16:25:46 +01:00
Hadi Moshayedi 15af1637aa Replicate reference tables to coordinator. 2019-11-15 05:50:19 -08:00
SaitTalhaNisanci b9b7fd7660
add IsLoggableLevel utility function (#3149)
* add IsLoggableLevel utility function

* add function comment for IsLoggableLevel

* put ApplyLogRedaction to logutils
2019-11-15 14:59:13 +03:00
Jelte Fennema 9fb897a074
Fix queries with repartition joins and group by unique column (#3157)
Postgres doesn't require you to add all columns that are in the target list to
the GROUP BY when you group by a unique column (or columns). It even actively
removes these group by clauses when you do.

This is normally fine, but for repartition joins it is not. The reason for this
is that the temporary tables don't have these primary key columns. So when the
worker executes the query it will complain that it is missing columns in the
group by.

This PR fixes that by adding an ANY_VALUE aggregate around each variable in
the target list that does is not contained in the group by or in an aggregate.
This is done only for repartition joins.

The ANY_VALUE aggregate chooses the value from an undefined row in the
group.
2019-11-08 15:36:18 +01:00
Önder Kalacı ffd89e4e01
Include all relevant relations in the ExtractRangeTableRelationWalker (#3135)
We've changed the logic for pulling RTE_RELATIONs in #3109 and
non-colocated subquery joins and partitioned tables.
@onurctirtir found this steps where I traced back and found the issues.

While looking into it in more detail, we decided to expand the list in a
way that the callers get all the relevant RTE_RELATIONs RELKIND_RELATION,
RELKIND_PARTITIONED_TABLE, RELKIND_FOREIGN_TABLE and RELKIND_MATVIEW.
These are all relation kinds that Citus planner is aware of.
2019-11-01 16:06:58 +01:00
SaitTalhaNisanci 94a7e6475c
Remove copyright years (#2918)
* Update year as 2012-2019

* Remove copyright years
2019-10-15 17:44:30 +03:00
Philip Dubé 74cb168205 Remove Postgres 10 support 2019-10-11 21:56:56 +00:00
Philip Dubé 68c4b71f93 Fix up includes with pg12 changes 2019-08-22 18:56:21 +00:00
Philip Dubé b77c52f95b PlanRouterQuery: don't store list of list of shard intervals in relationShardList 2019-08-02 14:08:57 +00:00
Philip Dubé 0915027389 DistributedPlan: replace operation with modLevel
This causes no behaviorial changes, only organizes better to implement modifying CTEs

Also rename ExtactInsertRangeTableEntry to ExtractResultRelationRTE,
as the source of this function didn't match the documentation

Remove Task's upsertQuery in favor of ROW_MODIFY_NONCOMMUTATIVE

Split up AcquireExecutorShardLock into more internal functions

Tests: Normalize multi_reference_table multi_create_table_constraints
2019-07-16 13:58:18 -07:00
exialin 59e54de54d Minor code clean-up 2019-05-24 14:26:26 +02:00
Hanefi Onaldi 4d737177e6
Remove redundant active placement filters and unneded sort operations
If a query is router executable, it hits a single shard and therefore has a
single task associated with it. Therefore there is no need to sort the task list
that has a single element.

Also we already have a list of active shard placements, sending it in param
and reuse it.
2019-05-24 14:16:50 +03:00
Jason Petersen 71d5d1c865 Enable variable shadowing warnings; fix all
Rather than wait for another place like the previous commit to bite us,
I think we should turn on this warning.
2019-04-30 13:24:25 -06:00
Hadi Moshayedi c9b1d9c2d1 Check all placements aren't inactive 2019-04-26 10:04:55 -07:00
Hadi Moshayedi 7b1d03772d Don't schedule tasks on inactive nodes. 2019-04-26 10:04:54 -07:00
Marco Slot 0ea4e52df5 Add nodeId to shardPlacements and use it for shard placement comparisons
Before this commit, shardPlacements were identified with shardId, nodeName
and nodeport. Instead of using nodeName and nodePort, we now use nodeId
since it apparently has performance benefits in several places in the
code.
2019-03-20 12:14:46 +03:00
Onder Kalaci f706772b2f Round-robin task assignment policy relies on local transaction id
Before this commit, round-robin task assignment policy was relying
on the taskId. Thus, even inside a transaction, the tasks were
assigned to different nodes. This was especially problematic
while reading from reference tables within transaction blocks.
Because, we had to expand the distributed transaction to many
nodes that are not necessarily already in the distributed transaction.
2019-02-22 19:26:38 +03:00
Onder Kalaci f144bb4911 Introduce fast path router planning
In this context, we define "Fast Path Planning for SELECT" as trivial
queries where Citus can skip relying on the standard_planner() and
handle all the planning.

For router planner, standard_planner() is mostly important to generate
the necessary restriction information. Later, the restriction information
generated by the standard_planner is used to decide whether all the shards
that a distributed query touches reside on a single worker node. However,
standard_planner() does a lot of extra things such as cost estimation and
execution path generations which are completely unnecessary in the context
of distributed planning.

There are certain types of queries where Citus could skip relying on
standard_planner() to generate the restriction information. For queries
in the following format, Citus does not need any information that the
standard_planner() generates:

  SELECT ... FROM single_table WHERE distribution_key = X;  or
  DELETE FROM single_table WHERE distribution_key = X; or
  UPDATE single_table SET value_1 = value_2 + 1 WHERE distribution_key = X;

Note that the queries might not be as simple as the above such that
GROUP BY, WINDOW FUNCIONS, ORDER BY or HAVING etc. are all acceptable. The
only rule is that the query is on a single distributed (or reference) table
and there is a "distribution_key = X;" in the WHERE clause. With that, we
could use to decide the shard that a distributed query touches reside on
a worker node.
2019-02-21 13:27:01 +03:00
Marco Slot 1656b519c4 Plan outer joins through pushdown planning 2019-01-05 20:55:27 +01:00
Murat Tuncer b389bebda1 Move repeated code to a function 2019-01-03 17:19:01 +03:00
Murat Tuncer 2ed7d24591 Fix having clause bug for complex joins
We update column attributes of various clauses for a query
inluding target columns, select clauses when we introduce
new range table entries in the query.

It seems having clause column attributes were not updated.

This fix resolves the issue
2019-01-03 17:07:26 +03:00
Onder Kalaci b6ebd791a6 Sort task list for multi-task explain outputs
This is purely for ensuring that regression tests do not randomly fail.
2018-11-30 11:19:37 -07:00
Nils Dijk f9520be011
Round robin queries to reference tables with task_assignment_policy set to `round-robin` (#2472)
Description: Support round-robin `task_assignment_policy` for queries to reference tables.

This PR allows users to query multiple placements of shards in a round robin fashion. When `citus.task_assignment_policy` is set to `'round-robin'` the planner will use a round robin scheduling feature when multiple shard placements are available.

The primary use-case is spreading the load of reference table queries to all the nodes in the cluster instead of hammering only the first placement of the reference table. Since reference tables share the same path for selecting the shards with single shard queries that have multiple placements (`citus.shard_replication_factor > 1`) this setting also allows users to spread the query load on these shards.

For modifying queries we do not apply a round-robin strategy. This would be negated by an extra reordering step in the executor for such queries where a `first-replica` strategy is enforced.
2018-11-15 15:11:15 +01:00
mehmet furkan şahin ef9f38b68d ApplyLogRedaction noop func is added 2018-08-17 14:48:54 -07:00
Marco Slot fd4ff29f2f Add a debug message with distribution column value 2018-06-05 15:09:17 +03:00
Onder Kalaci 317dd02a2f Implement single repartitioning on hash distributed tables
* Change worker_hash_partition_table() such that the
     divergence between Citus planner's hashing and
     worker_hash_partition_table() becomes the same.

   * Rename single partitioning to single range partitioning.

   * Add single hash repartitioning. Basically, logical planner
     treats single hash and range partitioning almost equally.
     Physical planner, on the other hand, treats single hash and
     dual hash repartitioning almost equally (except for JoinPruning).

   * Add a new GUC to enable this feature
2018-05-02 18:50:55 +03:00
velioglu 32bcd610c1 Support modify queries with multiple tables
With this commit we begin to support modify queries with multiple
tables if these queries are pushdownable.
2018-05-02 16:22:26 +03:00
velioglu d9fa69c031 Refactor query pushdown related logic 2018-05-02 15:03:09 +03:00
Murat Tuncer a6fe5ca183 PG11 compatibility update
- changes in ruleutils_11.c is reflected
- vacuum statement api change is handled. We now allow
  multi-table vacuum commands.
- some other function header changes are reflected
- api conflicts between PG11 and earlier versions
  are handled by adding shims in version_compat.h
- various regression tests are fixed due output and
  functionality in PG1
- no change is made to support new features in PG11
  they need to be handled by new commit
2018-04-26 11:29:43 +03:00
velioglu 1b92812be2 Add co-placement check to CoPartition function 2018-04-13 12:13:08 +03:00
Marco Slot ee132c5ead Prune shards once per relation in subquery pushdown 2018-04-10 20:33:07 +02:00
velioglu 72dfe4a289 Adds colocation check to local join 2018-04-04 22:49:27 +03:00
velioglu 698d585fb5 Remove broadcast join logic
After this change all the logic related to shard data fetch logic
will be removed. Planner won't plan any ShardFetchTask anymore.
Shard fetch related steps in real time executor and task-tracker
executor have been removed.
2018-03-30 11:45:19 +03:00
Murat Tuncer 76f6883d5d
Add support for window functions that can be pushed down to worker (#2008)
This is the first of series of window function work.

We can now support window functions that can be pushed down to workers.
Window function must have distribution column in the partition clause
 to be pushed down.
2018-03-01 19:07:07 +03:00
Onder Kalaci 0d5a4b9c72 Recursively plan subqueries that are not safe to pushdown
With this commit, Citus recursively plans subqueries that
are not safe to pushdown, in other words, requires a merge
step.

The algorithm is simple: Recursively traverse the query from bottom
up (i.e., bottom meaning the leaf queries). On each level, check
whether the query is safe to pushdown (or a single repartition
subquery). If the answer is yes, do not touch that subquery. If the
answer is no, plan the subquery seperately (i.e., create a subPlan
for it) and replace the subquery with a call to
`read_intermediate_results(planId, subPlanId)`. During the the
execution, run the subPlans first, and make them avaliable to the
next query executions.

Some of the queries hat this change allows us:

   * Subqueries with LIMIT
   * Subqueries with GROUP BY/DISTINCT on non-partition keys
   * Subqueries involving re-partition joins, router queries
   * Mixed usage of subqueries and CTEs (i.e., use CTEs in
     subqueries as well). Nested subqueries as long as we
     support the subquery inside the nested subquery.
   * Subqueries with local tables (i.e., those subqueries
     has the limitation that they have to be leaf subqueries)

   * VIEWs on the distributed tables just works (i.e., the
     limitations mentioned below still applies to views)

Some of the queries that is still NOT supported:

  * Corrolated subqueries that are not safe to pushdown
  * Window function on non-partition keys
  * Recursively planned subqueries or CTEs on the outer
    side of an outer join
  * Only recursively planned subqueries and CTEs in the FROM
    (i.e., not any distributed tables in the FROM) and subqueries
    in WHERE clause
  * Subquery joins that are not on the partition columns (i.e., each
    subquery is individually joined on partition keys but not the upper
    level subquery.)
  * Any limitation that logical planner applies such as aggregate
    distincts (except for count) when GROUP BY is on non-partition key,
    or array_agg with ORDER BY
2017-12-21 08:37:40 +02:00
Murat Tuncer 2d66bf5f16
Fix hard coded formatting strings for 64 bit numbers (#1831)
Postgres provides OS agnosting formatting macros for
formatting 64 bit numbers. Replaced %ld %lu with
INT64_FORMAT and UINT64_FORMAT respectively.

Also found some incorrect usages of formatting
flags and fixed them.
2017-12-04 14:11:06 +03:00
Marco Slot a9933deac6 Make real time executor work in transactions 2017-11-30 09:59:32 +03:00
Marco Slot 6ba3f42d23 Rename MultiPlan to DistributedPlan 2017-11-22 09:36:24 +01:00
velioglu 0b5db5d826 Support multi shard update/delete queries 2017-10-25 15:52:38 +03:00
Murat Tuncer f7ab901766 Add select distinct, and distinct on support
Distinct, and distinct on() clauses are supported
in simple selects, joins, subqueries, and insert into select
queries.
2017-10-13 14:59:48 +03:00
velioglu b0efffae1c Correct planner and add more tests 2017-08-11 10:16:13 +03:00
velioglu 7550b8ad52 Fix anchor shard id selection when reference table exists 2017-08-11 10:09:47 +03:00
velioglu ceba81ce35 Move physical planner checks to logical planner 2017-08-11 10:09:47 +03:00
velioglu 0359d03530 Add set operation check for reference tables 2017-08-11 10:09:47 +03:00
velioglu c4e3b8b5e1 Add planner changes and tests for subquery on reference tables 2017-08-11 10:09:47 +03:00
Brian Cloutier 9d93fb5551 Create citus.use_secondary_nodes GUC
This GUC has two settings, 'always' and 'never'. When it's set to
'never' all behavior stays exactly as it was prior to this commit. When
it's set to 'always' only SELECT queries are allowed to run, and only
secondary nodes are used when processing those queries.

Add some helper functions:
- WorkerNodeIsSecondary(), checks the noderole of the worker node
- WorkerNodeIsReadable(), returns whether we're currently allowed to
  read from this node
- ActiveReadableNodeList(), some functions (namely, the ones on the
  SELECT path) don't require working with Primary Nodes. They should call
  this function instead of ActivePrimaryNodeList(), because the latter
  will error out in contexts where we're not allowed to write to nodes.
- ActiveReadableNodeCount(), like the above, replaces
  ActivePrimaryNodeCount().
- EnsureModificationsCanRun(), error out if we're not currently allowed
  to run queries which modify data. (Either we're in read-only mode or
  use_secondary_nodes is set)

Some parts of the code were switched over to use readable nodes instead
of primary nodes:
- Deadlock detection
- DistributedTableSize,
- the router, real-time, and task tracker executors
- ShardPlacement resolution
2017-08-10 17:37:17 +03:00
Metin Doslu b8a9e7c1bf Add support for UPDATE/DELETE with subqueries 2017-08-08 21:35:08 +03:00
Brian Cloutier ec99f8f983 Add nodeRole column
- master_add_node enforces that there is only one primary per group
- there's also a trigger on pg_dist_node to prevent multiple primaries
  per group
- functions in metadata cache only return primary nodes
- Rename ActiveWorkerNodeList -> ActivePrimaryNodeList
- Rename WorkerGetLive{Node->Group}Count()
- Refactor WorkerGetRandomCandidateNode
- master_remove_node only complains about active shard placements if the
  node being removed is a primary.
- master_remove_node only deletes all reference table placements in the
  group if the node being removed is the primary.
- Rename {Node->NodeGroup}HasShardPlacements, this reflects the behavior it
  already had.
- Rename DeleteAllReferenceTablePlacementsFrom{Node->NodeGroup}. This also
  reflects the behavior it already had, but the new signature forces the
  caller to pass in a groupId
- Rename {WorkerGetLiveGroup->ActivePrimaryNode}Count
2017-07-24 11:57:46 +03:00
Brian Cloutier 7ad95b53d2 Rename pg_dist_shard_placement -> pg_dist_placement
Comes with a few changes:

- Change the signature of some functions to accept groupid
  - InsertShardPlacementRow
  - DeleteShardPlacementRow
  - UpdateShardPlacementState

- NodeHasActiveShardPlacements returns true if the group the node is a
  part of has any active shard placements

- TupleToShardPlacement now returns ShardPlacements which have NULL
  nodeName and nodePort.

- Populate (nodeName, nodePort) when creating ShardPlacements
- Disallow removing a node if it contains any shard placements

- DeleteAllReferenceTablePlacementsFromNode matches based on group. This
  doesn't change behavior for now (while there is only one node per
  group), but means in the future callers should be careful about
  calling it on a secondary node, it'll delete placements on the primary.

- Create concept of a GroupShardPlacement, which represents an actual
  tuple in pg_dist_placement and is distinct from a ShardPlacement,
  which has been resolved to a specific node. In the future
  ShardPlacement should be renamed to NodeShardPlacement.

- Create some triggers which allow existing code to continue to insert
  into and update pg_dist_shard_placement as if it still existed.
2017-07-12 14:17:31 +02:00
Önder Kalacı ef6d3587b6 Skip exhaustive test in CoPartitionedTables() if declared colocated (#1376)
That's considerably cheaper.
2017-05-02 03:33:21 +03:00
Önder Kalacı ad5cd326a4 Subquery pushdown - main branch (#1323)
* Enabling physical planner for subquery pushdown changes

This commit applies the logic that exists in INSERT .. SELECT
planning to the subquery pushdown changes.

The main algorithm is followed as :
   - pick an anchor relation (i.e., target relation)
   - per each target shard interval
       - add the target shard interval's shard range
         as a restriction to the relations (if all relations
         joined on the partition keys)
        - Check whether the query is router plannable per
          target shard interval.
        - If router plannable, create a task

* Add union support within the JOINS

This commit adds support for UNION/UNION ALL subqueries that are
in the following form:

     .... (Q1 UNION Q2 UNION ...) as union_query JOIN (QN) ...

In other words, we currently do NOT support the queries that are
in the following form where union query is not JOINed with
other relations/subqueries :

     .... (Q1 UNION Q2 UNION ...) as union_query ....

* Subquery pushdown planner uses original query

With this commit, we change the input to the logical planner for
subquery pushdown. Before this commit, the planner was relying
on the query tree that is transformed by the postgresql planner.
After this commit, the planner uses the original query. The main
motivation behind this change is the simplify deparsing of
subqueries.

* Enable top level subquery join queries

This work enables
- Top level subquery joins
- Joins between subqueries and relations
- Joins involving more than 2 range table entries

A new regression test file is added to reflect enabled test cases

* Add top level union support

This commit adds support for UNION/UNION ALL subqueries that are
in the following form:

     .... (Q1 UNION Q2 UNION ...) as union_query ....

In other words, Citus supports allow top level
unions being wrapped into aggregations queries
and/or simple projection queries that only selects
some fields from the lower level queries.

* Disallow subqueries without a relation in the range table list for subquery pushdown

This commit disallows subqueries without relation in the range table
list. This commit is only applied for subquery pushdown. In other words,
we do not add this limitation for single table re-partition subqueries.

The reasoning behind this limitation is that if we allow pushing down
such queries, the result would include (shardCount * expectedResults)
where in a non distributed world the result would be (expectedResult)
only.

* Disallow subqueries without a relation in the range table list for INSERT .. SELECT

This commit disallows subqueries without relation in the range table
list. This commit is only applied for INSERT.. SELECT queries.

The reasoning behind this limitation is that if we allow pushing down
such queries, the result would include (shardCount * expectedResults)
where in a non distributed world the result would be (expectedResult)
only.

* Change behaviour of subquery pushdown flag (#1315)

This commit changes the behaviour of the citus.subquery_pushdown flag.
Before this commit, the flag is used to enable subquery pushdown logic. But,
with this commit, that behaviour is enabled by default. In other words, the
flag is now useless. We prefer to keep the flag since we don't want to break
the backward compatibility. Also, we may consider using that flag for other
purposes in the next commits.

* Require subquery_pushdown when limit is used in subquery

Using limit in subqueries may cause returning incorrect
results. Therefore we allow limits in subqueries only
if user explicitly set subquery_pushdown flag.

* Evaluate expressions on the LIMIT clause (#1333)

Subquery pushdown uses orignal query, the LIMIT and OFFSET clauses
are not evaluated. However, logical optimizer expects these expressions
are already evaluated by the standard planner. This commit manually
evaluates the functions on the logical planner for subquery pushdown.

* Better format subquery regression tests (#1340)

* Style fix for subquery pushdown regression tests

With this commit we intented a more consistent style for the
regression tests we've added in the
  - multi_subquery_union.sql
  - multi_subquery_complex_queries.sql
  - multi_subquery_behavioral_analytics.sql

* Enable the tests that are temporarily commented

This commit enables some of the regression tests that were commented
out until all the development is done.

* Fix merge conflicts (#1347)

 - Update regression tests to meet the changes in the regression
   test output.
 - Replace Ifs with Asserts given that the check is already done
 - Update shard pruning outputs

* Add view regression tests for increased subquery coverage (#1348)

- joins between views and tables
- joins between views
- union/union all queries involving views
- views with limit
- explain queries with view

* Improve btree operators for the subquery tests

This commit adds the missing comprasion for subquery composite key
btree comparator.
2017-04-29 04:09:48 +03:00
Andres Freund d399f395f7 Faster shard pruning.
So far citus used postgres' predicate proofing logic for shard
pruning, except for INSERT and COPY which were already optimized for
speed.  That turns out to be too slow:
* Shard pruning for SELECTs is currently O(#shards), because
  PruneShardList calls predicate_refuted_by() for every
  shard. Obviously using an O(N) type algorithm for general pruning
  isn't good.
* predicate_refuted_by() is quite expensive on its own right. That's
  primarily because it's optimized for doing a single refutation
  proof, rather than performing the same proof over and over.
* predicate_refuted_by() does not keep persistent state (see 2.) for
  function calls, which means that a lot of syscache lookups will be
  performed. That's particularly bad if the partitioning key is a
  composite key, because without a persistent FunctionCallInfo
  record_cmp() has to repeatedly look-up the type definition of the
  composite key. That's quite expensive.

Thus replace this with custom-code that works in two phases:
1) Search restrictions for constraints that can be pruned upon
2) Use those restrictions to search for matching shards in the most
   efficient manner available:
   a) Binary search / Hash Lookup in case of hash partitioned tables
   b) Binary search for equal clauses in case of range or append
      tables without overlapping shards.
   c) Binary search for inequality clauses, searching for both lower
      and upper boundaries, again in case of range or append
      tables without overlapping shards.
   d) exhaustive search testing each ShardInterval

My measurements suggest that we are considerably, often orders of
magnitude, faster than the previous solution, even if we have to fall
back to exhaustive pruning.
2017-04-28 14:40:41 -07:00
Andres Freund b7dfeb0bec Boring regression test output adjustments.
Soon shard pruning will be optimized not to generally work linearly
anymore.  Thus we can't print the pruned shard intervals as currently
done anymore.

The current printing of shard ids also prevents us from running tests
in parallel, as otherwise shard ids aren't linearly numbered.
2017-04-26 11:33:56 -07:00
Marco Slot dfd7d86948 Stop using a sequence to generate unique job IDs 2017-04-18 11:31:51 +02:00
Burak Yucesoy e9095e62ec Decouple reference table replication
With this change we add an option to add a node without replicating all reference
tables to that node. If a node is added with this option, we mark the node as
inactive and no queries will sent to that node.

We also added two new UDFs;
 - master_activate_node(host, port):
    - marks node as active and replicates all reference tables to that node
 - master_add_inactive_node(host, port):
    - only adds node to pg_dist_node
2017-04-17 13:33:31 +03:00
Metin Doslu 1f838199f8 Use CustomScan API for query execution
Custom Scan is a node in the planned statement which helps external providers
to abstract data scan not just for foreign data wrappers but also for regular
relations so you can benefit your version of caching or hardware optimizations.
This sounds like only an abstraction on the data scan layer, but we can use it
as an abstraction for our distributed queries. The only thing we need to do is
to find distributable parts of the query, plan for them and replace them with
a Citus Custom Scan. Then, whenever PostgreSQL hits this custom scan node in
its Vulcano style execution, it will call our callback functions which run
distributed plan and provides tuples to the upper node as it scans a regular
relation. This means fewer code changes, fewer bugs and more supported features
for us!

First, in the distributed query planner phase, we create a Custom Scan which
wraps the distributed plan. For real-time and task-tracker executors, we add
this custom plan under the master query plan. For router executor, we directly
pass the custom plan because there is not any master query. Then, we simply let
the PostgreSQL executor run this plan. When it hits the custom scan node, we
call the related executor parts for distributed plan, fill the tuple store in
the custom scan and return results to PostgreSQL executor in Vulcano style,
a tuple per XXX_ExecScan() call.

* Modify planner to utilize Custom Scan node.
* Create different scan methods for different executors.
* Use native PostgreSQL Explain for master part of queries.
2017-03-14 12:17:51 +02:00
Andres Freund 52358fe891 Initial temp table removal implementation 2017-03-14 12:09:49 +02:00
Marco Slot 87ae26aef3 Ensure job IDs are unique across workers 2017-01-22 16:55:14 +01:00
Murat Tuncer e7935a3be4 Report error when original range table id is not found in NewTableId() 2017-01-13 09:39:43 +03:00
Onder Kalaci 6d050fd677 Use 2PC for reference table modification
With this commit, we ensure that router executor always uses
2PC for reference table modifications and never mark the placements
of it as INVALID.
2017-01-04 12:46:35 +02:00
Onder Kalaci 9f0bd4cb36 Reference Table Support - Phase 1
With this commit, we implemented some basic features of reference tables.

To start with, a reference table is
  * a distributed table whithout a distribution column defined on it
  * the distributed table is single sharded
  * and the shard is replicated to all nodes

Reference tables follows the same code-path with a single sharded
tables. Thus, broadcast JOINs are applicable to reference tables.
But, since the table is replicated to all nodes, table fetching is
not required any more.

Reference tables support the uniqueness constraints for any column.

Reference tables can be used in INSERT INTO .. SELECT queries with
the following rules:
  * If a reference table is in the SELECT part of the query, it is
    safe join with another reference table and/or hash partitioned
    tables.
  * If a reference table is in the INSERT part of the query, all
    other participating tables should be reference tables.

Reference tables follow the regular co-location structure. Since
all reference tables are single sharded and replicated to all nodes,
they are always co-located with each other.

Queries involving only reference tables always follows router planner
and executor.

Reference tables can have composite typed columns and there is no need
to create/define the necessary support functions.

All modification queries, master_* UDFs, EXPLAIN, DDLs, TRUNCATE,
sequences, transactions, COPY, schema support works on reference
tables as expected. Plus, all the pre-requisites associated with
distribution columns are dismissed.
2016-12-20 14:09:35 +02:00
Murat Tuncer c3a60bff70 Make router planner active at all times
We used to disable router planner and executor
when task executor is set to task-tracker.

This change enables router planning and execution
at all times regardless of task execution mode.

We are introducing a hidden flag enable_router_execution
to enable/disable router execution. Its default value is
true. User may disable router planning by setting it to false.
2016-12-20 11:24:01 +03:00
Onder Kalaci 1673ea937c Feature: INSERT INTO ... SELECT
This commit adds INSERT INTO ... SELECT feature for distributed tables.

We implement INSERT INTO ... SELECT by pushing down the SELECT to
each shard. To compute that we use the router planner, by adding
an "uninstantiated" constraint that the partition column be equal to a
certain value. standard_planner() distributes that constraint to all
the tables where it knows how to push the restriction safely. An example
is that the tables that are connected via equi joins.

The router planner then iterates over the target table's shards,
for each we replace the "uninstantiated" restriction, with one that
PruneShardList() handles. Do so by replacing the partitioning qual
parameter added in multi_planner() with the current shard's
actual boundary values. Also, add the current shard's boundary values to the
top level subquery to ensure that even if the partitioning qual is
not distributed to all the tables, we never run the queries on the shards
that don't match with the current shard boundaries. Finally, perform the
normal shard pruning to decide on whether to push the query to the
current shard or not.

We do not support certain SQLs on the subquery, which are described/commented
on ErrorIfInsertSelectQueryNotSupported().

We also added some locking on the router executor. When an INSERT/SELECT command
runs on a distributed table with replication factor >1, we need to ensure that
it sees the same result on each placement of a shard. So we added the ability
such that router executor takes exclusive locks on shards from which the SELECT
in an INSERT/SELECT reads in order to prevent concurrent changes. This is not a
very optimal solution, but it's simple and correct. The
citus.all_modifications_commutative can be used to avoid aggressive locking.
An INSERT/SELECT whose filters are known to exclude any ongoing writes can be
marked as commutative. See RequiresConsistentSnapshot() for the details.

We also moved the decison of whether the multiPlan should be executed on
the router executor or not to the planning phase. This allowed us to
integrate multi task router executor tasks to the router executor smoothly.
2016-10-26 10:01:00 +03:00
Marco Slot 9d98acfb6d Move requiresMasterEvaluation from Task to Job 2016-10-19 08:23:06 +02:00
Metin Doslu d03a2af778 Add HAVING support
This commit completes having support in Citus by adding having support for
real-time and task-tracker executors. Multiple tests are added to regression
tests to cover new supported queries with having support.
2016-10-13 15:47:53 +03:00
Andres Freund 982ad66753 Introduce placement IDs.
So far placements were assigned an Oid, but that was just used to track
insertion order. It also did so incompletely, as it was not preserved
across changes of the shard state. The behaviour around oid wraparound
was also not entirely as intended.

The newly introduced, explicitly assigned, IDs are preserved across
shard-state changes.

The prime goal of this change is not to improve ordering of task
assignment policies, but to make it easier to reference shards.  The
newly introduced UpdateShardPlacementState() makes use of that, and so
will the in-progress connection and transaction management changes.
2016-10-07 11:59:20 -07:00
Brian Cloutier 9d6699b07c Switch from pg_worker_list.conf file to pg_dist_node metadata table.
Related to #786

This change adds the `pg_dist_node` table that contains the information
about the workers in the cluster, replacing the previously used
`pg_worker_list.conf` file (or the one specified with `citus.worker_list_file`).

Upon update, `pg_worker_list.conf` file is read and `pg_dist_node` table is
populated with the file's content. After that, `pg_worker_list.conf` file
is renamed to `pg_worker_list.conf.obsolete`

For adding and removing nodes, the change also includes two new UDFs:
`master_add_node` and `master_remove_node`, which require superuser
permissions.

'citus.worker_list_file' guc is kept for update purposes but not used after the
update is finished.
2016-10-05 13:01:35 +03:00
Robin Thomas c507a0df1c During repartitions, the partitionColumnType argument sent to workers
is now a `::regtype` using the qualified name of the column type,
not the column type OID which may differ between master/worker nodes.
Test coverage of a hash reparitition using a UDT as the join column.

Note that the UDFs `worker_hash_partition_table` and `worker_range_partition_table`
are unchanged, and rightly expect an OID for the column type; but the
planner code building the commands now allows for `::regtype` casting
to do its magic.

Fixes citusdata/citus#111.
2016-10-03 13:41:20 -04:00
Marco Slot 3318288d75 Fix segmentation fault in case of joins with WHERE 1=0 2016-09-26 15:12:29 +02:00
Robin Thomas 010cbf16fc Remove all usage of pg_dist_shard.shardalias in extension code. (#739)
Remove regression test of non-null shardalias.
2016-08-19 17:06:22 +03:00
Burak Yucesoy 6f20af9e38 Remove schema name parameter from API functions
We remove schema name parameter from worker_fetch_foreign_file and
worker_fetch_regular_table functions. We now send schema name
concatanated with table name.
2016-07-28 20:41:05 +03:00
Burak Yucesoy a649b47bac Add old version(without schema name parameter) of api functions back
Fixes #676

We added old versions (i.e. without schema name) of worker_apply_shard_ddl_command,
worker_fetch_foreign_file and worker_fetch_regular_table back. During function call
of one of these functions, we set schema name as  public schema and call the newer
version of the functions.
2016-07-28 20:40:38 +03:00
Burak Yucesoy b58872b441
Fix worker_fetch_regular_table with schema
Fixes #504
Fixes #646

We changed signature of worker_fetch_regular_table to accept schema name as parameter to
make it work with schemas.
2016-07-22 00:44:02 -06:00
Jason Petersen 41ed433b0e
Remove hash-pruning logic for NULL values
It turns out some tests exercised this behavior, but removing it should
have no ill effects. Besides, both copy and INSERT disallow NULLs in a
table's partition column.

Fixes a bug where anti-joins on hash-partitioned distributed tables
would incorrectly prune shards early, result in incorrect results (test
included).
2016-07-06 17:04:21 -06:00
Andres Freund 2e8e8d377e Store ShardInterval instead of shardId in RangeTableFragments.
For CITUS_RTE_RELATION type fragments, reloading shardIntervals from the
database is rather expensive. So store a pointer to the full shard
interval, instead of just the shard id.  There's no new memory lifetime
hazards here, because we already passed a pointer to the shardInterval's
->shardId field around.

The plan time for the query in issue #607 goes from 2889 ms to 106 ms.
with this change.
2016-06-16 17:31:35 -07:00
Andres Freund 211a9721a9 Use cached comparator in ShardIntervalsOverlap().
By far the most expensive part of ShardIntervalsOverlap() is computing
the function to use to determine overlap. Luckily we already have that
computed and cached.

The plan time for the query in issue #607 goes from 8764 ms to 2889 ms
with this change.
2016-06-16 17:21:19 -07:00
Marco Slot 52bc209c37 Do not copy outer join clauses into WHERE 2016-06-16 16:42:32 -07:00
Murat Tuncer 20ba0f72a6 Change equality operator check for operator expressions 2016-06-06 12:34:16 +03:00
Murat Tuncer 2b0d6473b9 Add complex distinct count support for repartitioned subqueries
Single table repartition subqueries now support count(distinct column)
and count(distinct (case when ...)) expressions. Repartition query
extracts column used in aggregate expression and adds them to target
list and group by list, master query stays the same (count (distinct ...))
but attribute numbers inside the aggregate expression is modified to
reflect changes in repartition query.
2016-05-27 15:43:05 +03:00
Onder Kalaci 38da3c826b Fix compile time warning
This change fixes a compile time warning related to definition/declaration order
of the code.
2016-05-04 09:42:10 +03:00
Brian Cloutier 58535eb337 Query Planning Performance Improvments (#474)
- Only look at pruned shards when determining AnchorTable
- Use cached shardIntervalCompareFunction during copartition check
2016-05-03 10:48:46 +03:00
eren 7e19ebe679 FIX "mixed declarations and code" Warning in multi_physical_planner.c
Fixes #477

This change fixes the compile time warning message in BuildMapMergeJob in
multi_physical_planner.c about mixed declarations and code. Basically, the
problematic declaration is moved up so that no expression is before it.
2016-04-29 11:18:04 +03:00