Add compression setup to cryptocurrency tutorial

Author: antekresic

tutorials/blockchain-query/blockchain-compress.md

@@ -0,0 +1,107 @@
+---
+title: Query the Bitcoin blockchain - set up compression
+excerpt: Compress the dataset so you can store the Bitcoin blockchain more efficiently
+products: [cloud]
+keywords: [beginner, crypto, blockchain, Bitcoin, finance, analytics]
+layout_components: [next_prev_large]
+content_group: Query the Bitcoin blockchain
+---
+
+# Set up compression and compress the dataset
+
+This tutorial uses a dataset that contains Bitcoin blockchain data for
+the past five days, in a hypertable named `transactions`.
+
+<Collapsible heading="Setting up compression" defaultExpanded={false}>
+
+Storing a lot of blockchain data can be expensive. Using compression, you can store
+the same dataset much more efficiently and potentially query it even faster.
+
+## Compression setup
+
+1.  Connect to the Timescale database that contains the Bitcoin dataset.
+1.  At the psql prompt, run the ALTER command to enable compression on the hypertable:
+
+    ```sql
+    ALTER TABLE transactions 
+    SET (
+        timescaledb.compress, 
+        timescaledb.compress_segmentby='block_id', 
+        timescaledb.compress_orderby='time DESC'
+    );
+    ``` 
+1.  Compress all the chunks of the hypertable:
+    ```sql
+    SELECT compress_chunk(c) from show_chunks('transactions');
+    ```
+1.  See the dataset size before and after compression:
+    ```sql
+    SELECT 
+        pg_size_pretty(before_compression_total_bytes) as before,
+        pg_size_pretty(after_compression_total_bytes) as after,
+     FROM hypertable_compression_stats('transactions');
+    ```
+1.  The output should show considerable storage savings, something like this:
+    ```sql
+     before  | after  
+    ---------+--------
+    1307 MB | 237 MB   
+    (1 row)
+    ```
+</Collapsible>
+
+<Collapsible heading="Automatic compression" defaultExpanded={false}>
+## Automating compression
+
+If this was a production usecase, you could automate compression by adding a policy which would compress data after a certain age:
+
+```sql
+SELECT add_compression_policy('transactions', INTERVAL '8 days');
+```
+
+Previous command would compress the chunks after they reach 8 days of age.
+</Collapsible>
+
+<Collapsible heading="Taking advantage of query speedups" defaultExpanded={false}>
+## Faster analytical queries
+
+Previously, we have setup compression to be segmented by block_id column value.
+This means fetching data by filtering or grouping on that column will be fetched
+more efficiently. Ordering is also set to time descending so if we run queries
+which try to order data with that ordering, we should see performance benefits. 
+
+For instance, if we run the query example from previous section:
+```sql
+WITH recent_blocks AS (
+ SELECT block_id FROM transactions
+ WHERE is_coinbase IS TRUE
+ ORDER BY time DESC
+ LIMIT 5
+)
+SELECT
+ t.block_id, count(*) AS transaction_count,
+ SUM(weight) AS block_weight,
+ SUM(output_total_usd) AS block_value_usd
+FROM transactions t
+INNER JOIN recent_blocks b ON b.block_id = t.block_id
+WHERE is_coinbase IS NOT TRUE
+GROUP BY t.block_id;
+```
+
+We should see a decent performance difference when the dataset is compressed and
+when is decompressed. Try it yourself by running the previous query, decompressing
+the dataset and running it again while timing the execution time.
+
+You can decompress the whole dataset by running:
+```sql
+    SELECT decompress_chunk(c) from show_chunks('transactions');
+```
+
+On an example machine, we have observed a speedup of around two order of magnitude
+(15ms when compressed vs 1 second when decompressed).
+
+Try it yourself and see what you get!
+</Collapsible>
+
+[satoshi-def]: https://www.pcmag.com/encyclopedia/term/satoshi
+[coinbase-def]: https://www.pcmag.com/encyclopedia/term/coinbase-transaction

tutorials/blockchain-query/index.md

@@ -30,6 +30,7 @@ This tutorial covers:
 
 1.  [Setting up your dataset][blockchain-dataset]
 1.  [Querying your dataset][blockchain-query]
+1.  [Bonus: Store data efficiently][blockchain-compress]
 
 ## About querying the Bitcoin blockchain with Timescale
 
@@ -53,6 +54,7 @@ analyze the blockchain data using Timescale hyperfunctions.
 [cloud-install]: /getting-started/:currentVersion:/#create-your-timescale-account
 [blockchain-dataset]: /tutorials/:currentVersion:/blockchain-query/blockchain-dataset/
 [blockchain-query]: /tutorials/:currentVersion:/blockchain-query/beginner-blockchain-query/
+[blockchain-compress]: /tutorials/:currentVersion:/blockchain-query/blockchain-compress/
 [blockchain-def]: https://www.pcmag.com/encyclopedia/term/blockchain
 [transactions-def]: https://www.pcmag.com/encyclopedia/term/bitcoin-transaction
 [analyze-blockchain]: /tutorials/:currentVersion:/blockchain-analyze/