Postgresql Index Usage Analysis

sql

database-performance

index-optimization

postgresql

byNikita Barsukov·Nov 28, 2024

Quickly scrutinize the index usage in PostgreSQL by querying the pg_stat_user_indexes view and the pg_index. This quick check can help identify potential redundant indexes by looking for indexes with low usage metrics.

SELECT 
    t.relname AS table_name,
    i.relname AS index_name,
    s.idx_scan, 
    s.idx_tup_read, 
    s.idx_tup_fetch 
FROM 
    pg_stat_user_indexes s
JOIN 
    pg_index x ON s.indexrelid = x.indexrelid  -- 🧲 Attracting indexes
JOIN 
    pg_class t ON x.indrelid = t.oid -- Acquiring the table-y infinity stone
JOIN 
    pg_class i ON s.indexrelid = i.oid -- Fetching indexes (not the dog 🐶 job)
WHERE 
    s.idx_scan < 50;

Set appropriate conditions, like idx_scan < 50, to pinpoint indexes that could be underperforming or unused. Just remember, never drop an index based on just a single hasty observation - perform thorough analysis beforehand.

Dive deeper: Unravel the hidden stories

Fine-tune your database performance by going an extra mile in the index analysis. Here's how:

Identifying Scan Types:
- Leverage pg_stat_all_tables to measure index scans vs. sequence scans.
- High sequence scan numbers could predict a missing effective index.
Catch the Slowpokes:
- Use pg_stat_statements to catch those tardy queries unawares.
- You might stumble upon a need for combinatorial indexes for performance pep-up.
Assessing Table Sizes:
- Team pg_size_pretty with pg_stat_user_tables to comprehend table size metrics.
- Large tables tend to be sequence scan favourites, better indexing to the rescue!
Unused Indexes Alert:
- Put pg_stat_all_indexes in action to find underused indexes.
- These lurkers just eat up your storage and maintenance time, bust 'em.
Deconstruct Query Plans:
- Apply EXPLAIN ANALYZE to decode query execution plans.
- It's like CSI for your queries, pinpoint why a query is lagging and identify potential index helpers.
Third-party Assistants:
- Tools like PgHero pitch in with automated analysis and indexing advice.
- Log analyzers such as pgFouine spot the pesky queries making a dent in your performance.

Converse with indexes: The upkeep chronicles

Maintaining healthy, performant indexes in PostgreSQL is an ongoing chore. Regular monitoring and optimization ensure they're always on their A-game. PostgreSQL's wealth of statistical functions are your toolkit for this task.

Stay tuned for PostgreSQL upgrades promising new analysis tools (like pseudo-indexes) on the horizon. Meanwhile, get intimately familiar with the existing statistical views and wield them for all their worth.

Visualization: Translate DB lingo to human-speak

Imagine your database as a library, and the tables are each a book. The indexes are like bookmarks, optimizing your searches.

PostgreSQL Index Usage Analysis: Indexes to the rescue!

| Book (Table)   | Bookmark (Index) | Page Search Speed |
| -------------- | ---------------- | ----------------- |
| Customers      | 📑✅              | Fast 🚀           |
| Orders         | 🚫                | Slow 🐌           |
| Inventory      | 📑✅              | Fast 🚀           |

The right indexes ensure quick data retrieval. Like finding the exact page in a book with the help of a bookmark!

📑✅ = Index used effectively 🚫 = No index used, results in full table scan

Ensure your tables (books) have the ideal indexes (bookmarks) for quick and efficient data searches!

explain-codes / Sql / Postgresql Index Usage Analysis

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