SELECT sum(total_amount)
FROM orders
WHERE created_at > '2026-09-09';
user_id, so the plan scatters to
every shard in the group. Each shard computes a partial sum, and the router
sums the partial sums.
The following sections give the complete output of the query for EXPLAIN (NEKI_PLAN) and EXPLAIN (NEKI_PG_PLAN), in each of the four output formats.
Query planning explains the EXPLAIN
modes and their options.
EXPLAIN (NEKI_PLAN)
EXPLAIN (NEKI_PLAN, FORMAT TEXT)
SELECT sum(total_amount)
FROM orders
WHERE created_at > '2026-09-09';
TEXT with JSON, XML, or YAML for the other formats.
- TEXT
- JSON
- XML
- YAML
Aggregate [Ordered] (cost=0.00..2002.00 rows=1 width=32)
-> Collapse (cost=0.00..2002.00 rows=2 width=32)
-> Route [Scatter] (cost=0.00..2002.00 rows=2 width=32)
Query: SELECT sum(total_amount) FROM public.orders WHERE created_at > $1::timestamp without time zone
ShardGroup: user_data
[
{
"Plan": {
"Node Type": "Aggregate",
"Variant": "Ordered",
"Startup Cost": 0.00,
"Total Cost": 2002.00,
"Plan Rows": 1,
"Plan Width": 32,
"Aggregates": [
"pg_catalog.sum(sum(total_amount) /*0*/) :: out_0"
],
"Cost": {
"Self": {
"RowsProcessed": 2,
"Total": 0
},
"Subtree": {
"NetworkRows": 2,
"RemoteCalls": 2,
"RowsProcessed": 2,
"Total": 2002
}
},
"Plans": [
{
"Node Type": "Collapse",
"Startup Cost": 0.00,
"Total Cost": 2002.00,
"Plan Rows": 2,
"Plan Width": 32,
"Cost": {
"Subtree": {
"NetworkRows": 2,
"RemoteCalls": 2,
"Total": 2002
}
},
"Plans": [
{
"Node Type": "Route",
"Variant": "Scatter",
"Startup Cost": 0.00,
"Total Cost": 2002.00,
"Plan Rows": 2,
"Plan Width": 32,
"ColumnOutputMapping": "[-1]",
"OuterParams": "[0]",
"ParamTypes": "[text]",
"Query": "SELECT sum(total_amount) FROM public.orders WHERE created_at \u003e $1::timestamp without time zone",
"ShardGroupUid": "user_data",
"Cost": {
"Subtree": {
"NetworkRows": 2,
"RemoteCalls": 2,
"Total": 2002
}
}
}
]
}
]
}
}
]
<explain xmlns="http://www.postgresql.org/2009/explain">
<Query>
<Plan>
<Node-Type>Aggregate</Node-Type>
<Variant>Ordered</Variant>
<Startup-Cost>0.00</Startup-Cost>
<Total-Cost>2002.00</Total-Cost>
<Plan-Rows>1</Plan-Rows>
<Plan-Width>32</Plan-Width>
<Aggregates>pg_catalog.sum(sum(total_amount) /*0*/) :: out_0 </Aggregates>
<Cost>
<Self>
<RowsProcessed>2</RowsProcessed>
<Total>0</Total>
</Self>
<Subtree>
<NetworkRows>2</NetworkRows>
<RemoteCalls>2</RemoteCalls>
<RowsProcessed>2</RowsProcessed>
<Total>2002</Total>
</Subtree>
</Cost>
<Plans>
<Plan>
<Node-Type>Collapse</Node-Type>
<Startup-Cost>0.00</Startup-Cost>
<Total-Cost>2002.00</Total-Cost>
<Plan-Rows>2</Plan-Rows>
<Plan-Width>32</Plan-Width>
<Cost>
<Subtree>
<NetworkRows>2</NetworkRows>
<RemoteCalls>2</RemoteCalls>
<Total>2002</Total>
</Subtree>
</Cost>
<Plans>
<Plan>
<Node-Type>Route</Node-Type>
<Variant>Scatter</Variant>
<Startup-Cost>0.00</Startup-Cost>
<Total-Cost>2002.00</Total-Cost>
<Plan-Rows>2</Plan-Rows>
<Plan-Width>32</Plan-Width>
<ColumnOutputMapping>[-1]</ColumnOutputMapping>
<OuterParams>[0]</OuterParams>
<ParamTypes>[text]</ParamTypes>
<Query>SELECT sum(total_amount) FROM public.orders WHERE created_at > $1::timestamp without time zone</Query>
<ShardGroupUid>user_data</ShardGroupUid>
<Cost>
<Subtree>
<NetworkRows>2</NetworkRows>
<RemoteCalls>2</RemoteCalls>
<Total>2002</Total>
</Subtree>
</Cost>
</Plan>
</Plans>
</Plan>
</Plans>
</Plan>
</Query>
</explain>
- Plan:
Node Type: Aggregate
Variant: Ordered
Startup Cost: 0.00
Total Cost: 2002.00
Plan Rows: 1
Plan Width: 32
Aggregates:
- 'pg_catalog.sum(sum(total_amount) /*0*/) :: out_0'
Cost:
Self:
RowsProcessed: 2
Total: 0
Subtree:
NetworkRows: 2
RemoteCalls: 2
RowsProcessed: 2
Total: 2002
Plans:
- Node Type: Collapse
Startup Cost: 0.00
Total Cost: 2002.00
Plan Rows: 2
Plan Width: 32
Cost:
Subtree:
NetworkRows: 2
RemoteCalls: 2
Total: 2002
Plans:
- Node Type: Route
Variant: Scatter
Startup Cost: 0.00
Total Cost: 2002.00
Plan Rows: 2
Plan Width: 32
ColumnOutputMapping: '[-1]'
OuterParams: '[0]'
ParamTypes: '[text]'
Query: SELECT sum(total_amount) FROM public.orders WHERE created_at > $1::timestamp without time zone
ShardGroupUid: user_data
Cost:
Subtree:
NetworkRows: 2
RemoteCalls: 2
Total: 2002
Query shows the date literal as $1. Neki replaces literal
values with parameters before it looks up a plan, as Query plan cache and
protocols describes.
EXPLAIN (NEKI_PG_PLAN)
EXPLAIN (NEKI_PG_PLAN, FORMAT TEXT)
SELECT sum(total_amount)
FROM orders
WHERE created_at > '2026-09-09';
- TEXT
- JSON
- XML
- YAML
Aggregate [Ordered] (cost=0.00..2002.00 rows=1 width=32)
-> Collapse (cost=0.00..2002.00 rows=2 width=32)
-> Route [Scatter] (cost=0.00..2002.00 rows=2 width=32)
Query: SELECT sum(total_amount) FROM public.orders WHERE created_at > $1::timestamp without time zone
ShardGroup: user_data
All shard plans
-> Shard shard-a (cost=0.00..0.00 rows=0 width=0)
-> Aggregate (cost=2.45..2.46 rows=1 width=32)
-> Seq Scan on orders (cost=0.00..2.40 rows=18 width=5)
Filter: (created_at > ('2026-09-09'::cstring)::timestamp without time zone)
-> Shard shard-b (cost=0.00..0.00 rows=0 width=0)
-> Aggregate (cost=4.17..4.18 rows=1 width=32)
-> Seq Scan on orders (cost=0.00..4.10 rows=26 width=5)
Filter: (created_at > ('2026-09-09'::cstring)::timestamp without time zone)
[
{
"Plan": {
"Node Type": "Aggregate",
"Variant": "Ordered",
"Startup Cost": 0.00,
"Total Cost": 2002.00,
"Plan Rows": 1,
"Plan Width": 32,
"Aggregates": [
"pg_catalog.sum(sum(total_amount) /*0*/) :: out_0"
],
"Cost": {
"Self": {
"RowsProcessed": 2,
"Total": 0
},
"Subtree": {
"NetworkRows": 2,
"RemoteCalls": 2,
"RowsProcessed": 2,
"Total": 2002
}
},
"Plans": [
{
"Node Type": "Collapse",
"Startup Cost": 0.00,
"Total Cost": 2002.00,
"Plan Rows": 2,
"Plan Width": 32,
"Cost": {
"Subtree": {
"NetworkRows": 2,
"RemoteCalls": 2,
"Total": 2002
}
},
"Plans": [
{
"Node Type": "Route",
"Variant": "Scatter",
"Startup Cost": 0.00,
"Total Cost": 2002.00,
"Plan Rows": 2,
"Plan Width": 32,
"ColumnOutputMapping": "[-1]",
"OuterParams": "[0]",
"ParamTypes": "[text]",
"Query": "SELECT sum(total_amount) FROM public.orders WHERE created_at \u003e $1::timestamp without time zone",
"ShardGroupUid": "user_data",
"ShardPlans": {
"All": [
{
"ShardPlan": {
"Shard": "shard-a",
"Plan": {
"Node Type": "Aggregate",
"Strategy": "Plain",
"Partial Mode": "Simple",
"Parallel Aware": false,
"Async Capable": false,
"Startup Cost": 2.45,
"Total Cost": 2.46,
"Plan Rows": 1,
"Plan Width": 32,
"Disabled": false,
"Plans": [
{
"Node Type": "Seq Scan",
"Parent Relationship": "Outer",
"Parallel Aware": false,
"Async Capable": false,
"Relation Name": "orders",
"Alias": "orders",
"Startup Cost": 0.00,
"Total Cost": 2.40,
"Plan Rows": 18,
"Plan Width": 5,
"Disabled": false,
"Filter": "(created_at \u003e ('2026-09-09'::cstring)::timestamp without time zone)"
}
]
}
}
},
{
"ShardPlan": {
"Shard": "shard-b",
"Plan": {
"Node Type": "Aggregate",
"Strategy": "Plain",
"Partial Mode": "Simple",
"Parallel Aware": false,
"Async Capable": false,
"Startup Cost": 4.17,
"Total Cost": 4.18,
"Plan Rows": 1,
"Plan Width": 32,
"Disabled": false,
"Plans": [
{
"Node Type": "Seq Scan",
"Parent Relationship": "Outer",
"Parallel Aware": false,
"Async Capable": false,
"Relation Name": "orders",
"Alias": "orders",
"Startup Cost": 0.00,
"Total Cost": 4.10,
"Plan Rows": 26,
"Plan Width": 5,
"Disabled": false,
"Filter": "(created_at \u003e ('2026-09-09'::cstring)::timestamp without time zone)"
}
]
}
}
}
]
},
"Cost": {
"Subtree": {
"NetworkRows": 2,
"RemoteCalls": 2,
"Total": 2002
}
}
}
]
}
]
}
}
]
<explain xmlns="http://www.postgresql.org/2009/explain">
<Query>
<Plan>
<Node-Type>Aggregate</Node-Type>
<Variant>Ordered</Variant>
<Startup-Cost>0.00</Startup-Cost>
<Total-Cost>2002.00</Total-Cost>
<Plan-Rows>1</Plan-Rows>
<Plan-Width>32</Plan-Width>
<Aggregates>pg_catalog.sum(sum(total_amount) /*0*/) :: out_0 </Aggregates>
<Cost>
<Self>
<RowsProcessed>2</RowsProcessed>
<Total>0</Total>
</Self>
<Subtree>
<NetworkRows>2</NetworkRows>
<RemoteCalls>2</RemoteCalls>
<RowsProcessed>2</RowsProcessed>
<Total>2002</Total>
</Subtree>
</Cost>
<Plans>
<Plan>
<Node-Type>Collapse</Node-Type>
<Startup-Cost>0.00</Startup-Cost>
<Total-Cost>2002.00</Total-Cost>
<Plan-Rows>2</Plan-Rows>
<Plan-Width>32</Plan-Width>
<Cost>
<Subtree>
<NetworkRows>2</NetworkRows>
<RemoteCalls>2</RemoteCalls>
<Total>2002</Total>
</Subtree>
</Cost>
<Plans>
<Plan>
<Node-Type>Route</Node-Type>
<Variant>Scatter</Variant>
<Startup-Cost>0.00</Startup-Cost>
<Total-Cost>2002.00</Total-Cost>
<Plan-Rows>2</Plan-Rows>
<Plan-Width>32</Plan-Width>
<ColumnOutputMapping>[-1]</ColumnOutputMapping>
<OuterParams>[0]</OuterParams>
<ParamTypes>[text]</ParamTypes>
<Query>SELECT sum(total_amount) FROM public.orders WHERE created_at > $1::timestamp without time zone</Query>
<ShardGroupUid>user_data</ShardGroupUid>
<ShardPlans>
<All>
<ShardPlan>
<Shard>shard-a</Shard>
<Plan>
<Node-Type>Aggregate</Node-Type>
<Strategy>Plain</Strategy>
<Partial-Mode>Simple</Partial-Mode>
<Parallel-Aware>false</Parallel-Aware>
<Async-Capable>false</Async-Capable>
<Startup-Cost>2.45</Startup-Cost>
<Total-Cost>2.46</Total-Cost>
<Plan-Rows>1</Plan-Rows>
<Plan-Width>32</Plan-Width>
<Disabled>false</Disabled>
<Plans>
<Plan>
<Node-Type>Seq Scan</Node-Type>
<Parent-Relationship>Outer</Parent-Relationship>
<Parallel-Aware>false</Parallel-Aware>
<Async-Capable>false</Async-Capable>
<Relation-Name>orders</Relation-Name>
<Alias>orders</Alias>
<Startup-Cost>0.00</Startup-Cost>
<Total-Cost>2.40</Total-Cost>
<Plan-Rows>18</Plan-Rows>
<Plan-Width>5</Plan-Width>
<Disabled>false</Disabled>
<Filter>(created_at > ('2026-09-09'::cstring)::timestamp without time zone)</Filter>
</Plan>
</Plans>
</Plan>
</ShardPlan>
<ShardPlan>
<Shard>shard-b</Shard>
<Plan>
<Node-Type>Aggregate</Node-Type>
<Strategy>Plain</Strategy>
<Partial-Mode>Simple</Partial-Mode>
<Parallel-Aware>false</Parallel-Aware>
<Async-Capable>false</Async-Capable>
<Startup-Cost>4.17</Startup-Cost>
<Total-Cost>4.18</Total-Cost>
<Plan-Rows>1</Plan-Rows>
<Plan-Width>32</Plan-Width>
<Disabled>false</Disabled>
<Plans>
<Plan>
<Node-Type>Seq Scan</Node-Type>
<Parent-Relationship>Outer</Parent-Relationship>
<Parallel-Aware>false</Parallel-Aware>
<Async-Capable>false</Async-Capable>
<Relation-Name>orders</Relation-Name>
<Alias>orders</Alias>
<Startup-Cost>0.00</Startup-Cost>
<Total-Cost>4.10</Total-Cost>
<Plan-Rows>26</Plan-Rows>
<Plan-Width>5</Plan-Width>
<Disabled>false</Disabled>
<Filter>(created_at > ('2026-09-09'::cstring)::timestamp without time zone)</Filter>
</Plan>
</Plans>
</Plan>
</ShardPlan>
</All>
</ShardPlans>
<Cost>
<Subtree>
<NetworkRows>2</NetworkRows>
<RemoteCalls>2</RemoteCalls>
<Total>2002</Total>
</Subtree>
</Cost>
</Plan>
</Plans>
</Plan>
</Plans>
</Plan>
</Query>
</explain>
- Plan:
Node Type: Aggregate
Variant: Ordered
Startup Cost: 0.00
Total Cost: 2002.00
Plan Rows: 1
Plan Width: 32
Aggregates:
- 'pg_catalog.sum(sum(total_amount) /*0*/) :: out_0'
Cost:
Self:
RowsProcessed: 2
Total: 0
Subtree:
NetworkRows: 2
RemoteCalls: 2
RowsProcessed: 2
Total: 2002
Plans:
- Node Type: Collapse
Startup Cost: 0.00
Total Cost: 2002.00
Plan Rows: 2
Plan Width: 32
Cost:
Subtree:
NetworkRows: 2
RemoteCalls: 2
Total: 2002
Plans:
- Node Type: Route
Variant: Scatter
Startup Cost: 0.00
Total Cost: 2002.00
Plan Rows: 2
Plan Width: 32
ColumnOutputMapping: '[-1]'
OuterParams: '[0]'
ParamTypes: '[text]'
Query: SELECT sum(total_amount) FROM public.orders WHERE created_at > $1::timestamp without time zone
ShardGroupUid: user_data
ShardPlans:
All:
- ShardPlan:
Shard: shard-a
Plan:
Node Type: "Aggregate"
Strategy: "Plain"
Partial Mode: "Simple"
Parallel Aware: false
Async Capable: false
Startup Cost: 2.45
Total Cost: 2.46
Plan Rows: 1
Plan Width: 32
Disabled: false
Plans:
- Node Type: "Seq Scan"
Parent Relationship: "Outer"
Parallel Aware: false
Async Capable: false
Relation Name: "orders"
Alias: "orders"
Startup Cost: 0.00
Total Cost: 2.40
Plan Rows: 18
Plan Width: 5
Disabled: false
Filter: "(created_at > ('2026-09-09'::cstring)::timestamp without time zone)"
- ShardPlan:
Shard: shard-b
Plan:
Node Type: "Aggregate"
Strategy: "Plain"
Partial Mode: "Simple"
Parallel Aware: false
Async Capable: false
Startup Cost: 4.17
Total Cost: 4.18
Plan Rows: 1
Plan Width: 32
Disabled: false
Plans:
- Node Type: "Seq Scan"
Parent Relationship: "Outer"
Parallel Aware: false
Async Capable: false
Relation Name: "orders"
Alias: "orders"
Startup Cost: 0.00
Total Cost: 4.10
Plan Rows: 26
Plan Width: 5
Disabled: false
Filter: "(created_at > ('2026-09-09'::cstring)::timestamp without time zone)"
Cost:
Subtree:
NetworkRows: 2
RemoteCalls: 2
Total: 2002