Couchbase Query Workbench Enhancements By Eben Haber

Confidential and Proprietary. Do not distribute without Couchbase consent. © Couchbase 2017. All rights reserved.

QUERY WORKBENCH IMPROVEMENTSWhat’s New in Couchbase 5.0

Confidential and Proprietary. Do not distribute without Couchbase consent. © Couchbase 2017. All rights reserved. 2

Eben Haber

Senior Software Engineer & User Advocate

LinkedIn – https://www.linkedin.com/in/ebenhaber

Your Presenter

https://www.linkedin.com/in/ebenhaber


OBJECTIVES1

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Query Workbench

Query Monitoring

Demo

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1QUERY WORKBENCH ENHANCEMENTS

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Query Plans in the Query Workbench

• Plans help explain query performance

• New “Explain” button – get the query plan without

adding “explain” keyword

• Workbench also automatically runs “Explain” with

every query. Plans stored in the Query History, so

you can re-examine plans from prior queries

• Workbench queries also set ‘collect timings’

parameter, plan result shows time spent in each

operator

• Even better, now supports visual query plans


Visual Query Plan

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Visual Query Plan (Explain)

Textual query plans are lengthy and hard to read. Version 5.0 now supports Visual query plans.

Shows the query execution plan in easy to understand visual flow diagrams and additionally provide other useful information.

Each visual query plan displays

• summary of buckets, fields, indexes used in query

• visual tree of query operators,

After query execution, can show:

• time spent per operator

• cost of each operator as a percentage of the total cost of the plan

• number of items processed (input & output)

• highlighted expensive operators


Schema Inferencing/INFER

• No fixed schemas in Couchbase

• Document structure can evolve as the developer sees fit

• Yet documents usually share common structure(s)

• INFER command (added in 4.5) randomly samples documents from a bucket,

produces schema(s) (compatable with http://json-schema.org)

• Based on a random sample, schemas are a “guess”, may miss rare elements

• In 5.0:

• Workbench automatically infers schemas for each bucket in background

• Schemas come up more quickly in Bucket Insights Panel

• Field/Index names available for auto-completion when writing queries

• Workbench also shows document counts for each bucket

http://json-schema.org


Schema Inferencing and Query Checking

• Couchbase has no fixed schema, can’t normally detect typos/non-existent fields

• Instead of a syntax error, you get unexpected result

• Release 5.0 has partial solution:

• Workbench automatically does schema inferencing (INFER) on each bucket.

• Inferred schema, combined with query plan, can identify some misspelled/incorrect field names

• False positives for very rare fields, not found by INFER

• False negatives for nested queries and expressions (e.g., ARRAY) not processed in query plan


Query History maintains a history of all

the queries executed on the Query

Workbench

• scroll through the history window or

use arrow keys at the top of the

editor to navigate

• search the query history by entering

a text in the search box located on

the top

• delete the currently selected query

from the history

• delete all the entire query history

Enhanced Query History


Query Preferences

Query Preferences provides you with ability to

change the run-time settings for Query Service

through Run-Time Preferences window

- Collect query timings

- Max Parallelism

- Scan Consistency

- Positional Parameters

- Named Parameters

- (or regular query HTTP params, if “$” omitted)

- Query Timeout (default 5 min)


Query Import/Export

Query Import/Export provides you with tools to

• Load the saved query from a file into the Query

Editor

• Export the query statement in the .txt format

• Export the query results in the JSON format


2QUERY MONITORING

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Query Monitoring

Since 4.5, Couchbase provided node-specific query information: e.g., system:active_requests

In 5.0, global query information, i.e. details of queries that are “active” (currently running), “completed” (recently run), or “prepared” (aggregate statistics for prepared queries) and ability to cancel/kill long-running queries.

Query Monitoring UI displays

• Active Queries – all running queries are displayed, with details such as the query text, the node IP address, duration, request identification number, and the current state of the query. Additionally, provide ability to cancel a long running query.

• Completed Queries – all completed queries that took longer than 1 second, with details as above plus result count and timestamp.

• Prepared Queries - aggregate statistics for prepared queries, e.g., query syntax, average elapsed time, and number of invokations.


Query Monitoring

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3 DEMO !!!

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THANK YOU!