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Example of explain output for a relationship lookup with a limit - Amazon Neptune

Example of explain output for a relationship lookup with a limit

This query looks for relationships between two anonymous nodes with type route, and returns at most 10. Again, the explain mode is details and the output format is the default ASCII format.

Here, DFEPipelineScan scans for edges that start from anonymous node ?anon_node7 and end at another anonymous node ?anon_node21, with a relationship type saved as ?p_type1. There is a filter for ?p_type1 being el://route (where el stands for edge label), which corresponds to [p:route] in the query string.

DFEDrain collects the output solution with a limit of 10, as shown in its Arguments column. DFEDrain terminates once the limit is reached or the all solutions are produced, whichever happens first.

To invoke explain for this query:

AWS CLI
aws neptunedata execute-open-cypher-explain-query \
  --endpoint-url https://your-neptune-endpoint:port \
  --open-cypher-query "MATCH ()-[p:route]->() RETURN p LIMIT 10" \
  --explain-mode details

For more information, see execute-open-cypher-explain-query in the AWS CLI Command Reference.

SDK
import boto3
from botocore.config import Config

client = boto3.client(
    'neptunedata',
    endpoint_url='https://your-neptune-endpoint:port',
    config=Config(read_timeout=None, retries={'total_max_attempts': 1})
)

response = client.execute_open_cypher_explain_query(
    openCypherQuery='MATCH ()-[p:route]->() RETURN p LIMIT 10',
    explainMode='details'
)

print(response['results'].read().decode('utf-8'))

For AWS SDK examples in other languages, see AWS SDK.

awscurl
awscurl https://your-neptune-endpoint:port/openCypher \
  --region us-east-1 \
  --service neptune-db \
  -X POST \
  -d "query=MATCH ()-[p:route]->() RETURN p LIMIT 10" \
  -d "explain=details"
Note

This example assumes that your AWS credentials are configured in your environment. Replace us-east-1 with the Region of your Neptune cluster.

curl
curl https://your-neptune-endpoint:port/openCypher \
  -d "query=MATCH ()-[p:route]->() RETURN p LIMIT 10" \
  -d "explain=details"

The explain output:

Query:
MATCH ()-[p:route]->() RETURN p LIMIT 10

╔════╤════════╤════════╤═══════════════════╤════════════════════╤═════════════════════╤══════════╤═══════════╤═══════╤═══════════╗
║ ID │ Out #1 │ Out #2 │ Name              │ Arguments          │ Mode                │ Units In │ Units Out │ Ratio │ Time (ms) ║
╠════╪════════╪════════╪═══════════════════╪════════════════════╪═════════════════════╪══════════╪═══════════╪═══════╪═══════════╣
║ 0  │ 1      │ -      │ SolutionInjection │ solutions=[{}]     │ -                   │ 0        │ 1         │ 0.00  │ 0         ║
╟────┼────────┼────────┼───────────────────┼────────────────────┼─────────────────────┼──────────┼───────────┼───────┼───────────╢
║ 1  │ 2      │ -      │ DFESubquery       │ subQuery=subQuery1 │ -                   │ 0        │ 10        │ 0.00  │ 5.00      ║
╟────┼────────┼────────┼───────────────────┼────────────────────┼─────────────────────┼──────────┼───────────┼───────┼───────────╢
║ 2  │ -      │ -      │ TermResolution    │ vars=[?p]          │ id2value_opencypher │ 10       │ 10        │ 1.00  │ 1.00      ║
╚════╧════════╧════════╧═══════════════════╧════════════════════╧═════════════════════╧══════════╧═══════════╧═══════╧═══════════╝


subQuery1
╔════╤════════╤════════╤═════════════════╤═══════════════════════════════════════════════════════════╤══════╤══════════╤═══════════╤═══════╤═══════════╗
║ ID │ Out #1 │ Out #2 │ Name            │ Arguments                                                 │ Mode │ Units In │ Units Out │ Ratio │ Time (ms) ║
╠════╪════════╪════════╪═════════════════╪═══════════════════════════════════════════════════════════╪══════╪══════════╪═══════════╪═══════╪═══════════╣
║ 0  │ 1      │ -      │ DFEPipelineScan │ pattern=Edge((?anon_node7)-[?p:?p_type1]->(?anon_node21)) │ -    │ 0        │ 1000      │ 0.00  │ 0.66      ║
║    │        │        │                 │ inlineFilters=[(?p_type1 IN [<el://route>])]              │      │          │           │       │           ║
║    │        │        │                 │ patternEstimate=26219                                     │      │          │           │       │           ║
╟────┼────────┼────────┼─────────────────┼───────────────────────────────────────────────────────────┼──────┼──────────┼───────────┼───────┼───────────╢
║ 1  │ 2      │ -      │ DFEProject      │ columns=[?p]                                              │ -    │ 1000     │ 1000      │ 1.00  │ 0.14      ║
╟────┼────────┼────────┼─────────────────┼───────────────────────────────────────────────────────────┼──────┼──────────┼───────────┼───────┼───────────╢
║ 2  │ -      │ -      │ DFEDrain        │ limit=10                                                  │ -    │ 1000     │ 0         │ 0.00  │ 0.11      ║
╚════╧════════╧════════╧═════════════════╧═══════════════════════════════════════════════════════════╧══════╧══════════╧═══════════╧═══════╧═══════════╝