Index patterns for time-series in Elasticsearch - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is an index pattern in Elasticsearch?

An index pattern is a way to tell Elasticsearch which indexes you want to search or analyze. It uses wildcards to match multiple indexes, especially useful for time-series data that creates new indexes over time.

beginner

Why use index patterns for time-series data?

Time-series data grows by adding new indexes for each time period (like daily or monthly). Index patterns let you search across all these indexes easily without specifying each one.

beginner

Example of an index pattern for daily logs from January 2024

If your daily indexes are named like 'logs-2024.01.01', 'logs-2024.01.02', etc., the index pattern would be 'logs-2024.01.*' to match all January 2024 logs.

intermediate

How does using index patterns improve performance?

By targeting only relevant indexes with patterns, Elasticsearch avoids searching unnecessary data. This makes queries faster and reduces resource use.

beginner

What wildcard character is used in Elasticsearch index patterns?

The asterisk (*) is used as a wildcard to match any characters in index names, helping to select multiple indexes with one pattern.

What does the index pattern 'metrics-2023.*' match?

A All indexes containing 'metrics' anywhere

B Only the index named 'metrics-2023.*'

C All indexes starting with 'metrics-2023.'

D Indexes from any year

The asterisk (*) matches any characters after 'metrics-2023.', so it matches all indexes starting with that prefix.

Why are index patterns useful for time-series data?

A They create new indexes

B They compress data automatically

C They delete old indexes

D They allow searching multiple time-based indexes at once

Index patterns let you search many time-based indexes together without naming each one.

If your indexes are named 'logs-2024.06.01', 'logs-2024.06.02', which index pattern matches all June 2024 logs?

A logs-2024.07.*

B logs-2024.06.*

C logs-*

D logs-2024.*

The pattern 'logs-2024.06.*' matches all indexes for June 2024.

What symbol is used as a wildcard in Elasticsearch index patterns?

A *

B ?

C #

D %

The asterisk (*) is the wildcard symbol in Elasticsearch index patterns.

How do index patterns help with query performance?

A By limiting queries to relevant indexes only

B By increasing the number of indexes searched

C By encrypting data

D By backing up indexes

Index patterns help Elasticsearch search only the needed indexes, making queries faster.

Explain what an index pattern is and why it is important for managing time-series data in Elasticsearch.

Think about how daily or monthly data is stored and how you can search it easily.

Describe how using index patterns can improve query performance when working with large time-series datasets.

Consider what happens if you search all data vs. only relevant parts.

Practice

1. What is the main purpose of using index patterns in Elasticsearch for time-series data?

easy

A. To group multiple time-based indexes for easier searching

B. To store data permanently without deletion

C. To create visual dashboards automatically

D. To encrypt data in the indexes

Solution

1. Step 1: Understand index patterns role

   Index patterns help combine many time-based indexes so you can search them all at once.

2. Step 2: Compare options

   Only grouping multiple time-based indexes matches the main purpose; others are unrelated.

3. Final Answer:

   To group multiple time-based indexes for easier searching -> Option A

4. Quick Check:

   Index patterns = group time-based indexes [OK]

Hint: Index patterns group many indexes by time for easy search [OK]

Common Mistakes:

• Thinking index patterns store data permanently
• Confusing index patterns with dashboards
• Assuming index patterns encrypt data

2. Which of the following is the correct syntax for an index pattern matching daily logs from January 2024 in Elasticsearch?

easy

A. logs-2024.01.*

B. logs-2024-01-*

C. logs_2024-01-*

D. logs-01-2024-*

Solution

1. Step 1: Identify date format in index pattern

   Elasticsearch uses dash-separated date parts like YYYY-MM-DD, so logs-2024-01-* matches daily logs in January 2024.

2. Step 2: Check other options

   logs-2024.01.* uses dots instead of dashes, which is incorrect. logs_2024-01-* uses underscore instead of dash. logs-01-2024-* has wrong order of date parts.

3. Final Answer:

   <code>logs-2024-01-*</code> -> Option B

4. Quick Check:

   Date format YYYY-MM-DD with dashes = logs-2024-01-* [OK]

Hint: Use dashes YYYY-MM-DD in index patterns for dates [OK]

Common Mistakes:

• Using dots instead of dashes in date format
• Mixing underscores and dashes incorrectly
• Reordering date parts wrongly

3. Given the index pattern metrics-2023.12.* and indexes metrics-2023.12.01, metrics-2023.11.30, metrics-2023.12.15, which indexes will match the pattern?

medium

A. metrics-2023.11.30 only

B. All three indexes

C. metrics-2023.12.01 and metrics-2023.12.15

D. None of the indexes

Solution

1. Step 1: Understand the pattern metrics-2023.12.*

   This pattern matches indexes starting with 'metrics-2023.12.' followed by anything, so it matches December 2023 indexes.

2. Step 2: Check each index

   metrics-2023.12.01 and metrics-2023.12.15 match December 2023; metrics-2023.11.30 is November, so it does not match.

3. Final Answer:

   <code>metrics-2023.12.01</code> and <code>metrics-2023.12.15</code> -> Option C

4. Quick Check:

   Pattern matches December indexes only = metrics-2023.12.01 and metrics-2023.12.15 [OK]

Hint: Wildcards match only after specified prefix [OK]

Common Mistakes:

• Assuming wildcard matches all months
• Ignoring exact prefix before wildcard
• Confusing dot and dash separators

4. You created an index pattern logs-2023-1* to match logs from January 2023, but it also matches October and November indexes. What is the likely mistake?

medium

A. The dash (-) should be a dot (.) in the pattern

B. Index patterns cannot match months, only years

C. The pattern should be logs-2023-1? instead of *

D. Using wildcard * after 1 matches months starting with 1 and 10

Solution

1. Step 1: Analyze wildcard usage in logs-2023-1*

   The wildcard * matches any characters after '1', so it matches '1...' (January) but also '10', '11' because '10' and '11' start with '1' in pattern matching.

2. Step 2: Understand why October and November match

   Because the pattern matches any string starting with '1', it also matches '10' and '11' incorrectly.

3. Final Answer:

   Using wildcard * after 1 matches months starting with 1 and 10 -> Option D

4. Quick Check:

   Wildcard * after 1 matches more than intended = Using wildcard * after 1 matches months starting with 1 and 10 [OK]

Hint: Wildcard * matches any characters, not just one digit [OK]

Common Mistakes:

• Thinking * matches only one character
• Confusing dash and dot separators
• Believing index patterns can't match months

5. You want to create an index pattern that matches all daily indexes for the year 2024 named like events-2024-03-15. Which pattern correctly matches all days in March 2024 but excludes other months?

hard

A. events-2024-03-??

B. events-2024-03-* and events-2024-04-*

C. events-2024-03-??*

D. events-2024-03-*

Solution

1. Step 1: Understand pattern to match daily dates

   Daily indexes have two-digit day numbers, so ?? matches exactly two characters (days 01 to 31).

2. Step 2: Compare options

   events-2024-03-* uses *, which matches any length, possibly including invalid days. events-2024-03-?? uses ?? to match exactly two digits. events-2024-03-??* allows extra characters after two digits, which is incorrect. events-2024-03-* and events-2024-04-* includes April, which should be excluded.

3. Final Answer:

   <code>events-2024-03-??</code> -> Option A

4. Quick Check:

   Two-question marks match exact two-digit days = events-2024-03-?? [OK]

Hint: Use ?? to match exactly two characters (days) in index pattern [OK]

Common Mistakes:

• Using * which matches any length, not exact days
• Including extra months by mistake
• Using patterns that allow invalid day formats