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Analyzing random number generation to 1 trillion using SQL, Python, C#

SQL

by Mountain Computers Inc, Publication Date: Saturday, October 18, 2025

View Count: 233, Keywords: C#, Python, SQL - Random Number Generation, Hashtags: #C# #Python #SQL-RandomNumberGeneration



One of the challenges in random number generation to 1 trillion records is speed.
 
In C# to file I/O is no problem. 1 billion in say 14 minutes. Times 1000 would be 14000 minutes. No problem. Even the file storage requirements is not that hard.
 
Now think about SQL and its overhead. I had to work on this for a moment. Then I noticed Python and its ability. Wow, that was stunning.
 
I asked ChatGPT and this is what they came up with.
 
more to come...
 
in sql server on a 16 core 32 thread computer, how long does it take to insert 1 trillion rows that are 4 columns wide?
 
ChatGPT said:

Inserting 1 trillion rows into a SQL Server database, even on a powerful 16-core / 32-thread machine, is a massive operation and depends on a wide range of factors. There's no universal answer, but I’ll break down the key factors and provide an estimated range to help you understand the scale.


🔧 Key Factors Affecting Insert Time

  1. Disk I/O Speed

    • Are you using SSDs, NVMe, or spinning disks?

    • Throughput and latency will greatly impact performance.

  2. Row Size & Table Design

    • How wide are the columns? Are they fixed-size (e.g., INT, BIGINT) or variable (e.g., VARCHAR)?

    • Presence of constraints, indexes, triggers, etc.

  3. Batching Strategy

    • Single row inserts are slow.

    • Bulk inserts using batches of 10,000–100,000 rows are much faster.

  4. Transaction Management

    • Committing per row = slow.

    • Committing per batch or in a single large transaction = faster, but more memory-intensive.

  5. Parallelism

    • Are you parallelizing inserts across all 32 threads?

    • Using SSIS, BULK INSERT, or SqlBulkCopy?

  6. Logging & Recovery Model

    • Full recovery model = more logging = slower.

    • Minimal logging (with TABLOCK + simple/bulk-logged model) can improve speed drastically.

  7. Target Table Structure

    • Heap vs. clustered index.

    • Indexes on the table slow down inserts.


📐 Back-of-the-Napkin Estimate

Let’s assume:

  • 4 columns, all integers (4 bytes each), so row size ~16 bytes.

  • Bulk insert with SqlBulkCopy, minimal logging, SSD/NVMe.

  • Batching and multi-threaded parallel insert optimized.

  • Minimal indexing.

Data Size:

1 trillion rows × 16 bytes = ~16 TB of raw data (not including overhead, transaction logs, indexes).


⚙️ Realistic Insert Speeds

Good case (optimized):

  • You can reach around 100,000 rows/second per thread under ideal conditions.

  • With 32 threads fully utilized:
    100,000 × 32 = 3.2 million rows/sec

⏱️ 1,000,000,000,000 / 3,200,000 ≈ 312,500 seconds = ~87 hours (~3.6 days)

Average case (non-optimized):

  • Let's say only 1 million rows/sec aggregate.

  • That’s 1 trillion / 1 million = 1 million seconds ≈ 11.6 days


🧪 Rule of Thumb Summary

Scenario Rows/sec Time to Insert 1T Rows
Ideal (fully optimized) 3.2M+ ~3.5 days
Moderate optimization 1M ~11.6 days
Poor (row-by-row inserts, full logging) 10K–100K Weeks to months

✅ Tips to Speed Things Up

  • Use BULK INSERT or SqlBulkCopy

  • Switch to simple recovery model during load

  • Use minimal logging with TABLOCK

  • Drop all indexes and constraints before insert

  • Partition the data for parallel loading

  • Consider staging tables and post-processing


Would you like help building a script or testing benchmarks with your schema?

 
You said:
what if it were 4 colums?
 
ChatGPT said:

Great question! Let's refine the estimate, now explicitly assuming 4 columns. I’ll go over it again with specific attention to row width and performance implications.


🧩 Scenario Setup

Let’s define the row and data characteristics more concretely.

🧮 Assumptions:

  • 4 columns, each of type INT (4 bytes)
    → Total row size: 16 bytes

  • 1 trillion rows

  • Inserted using efficient bulk method (e.g., BULK INSERT, SqlBulkCopy, or bcp utility)

  • No indexes or constraints

  • Minimal logging (simple or bulk-logged recovery mode)

  • High-speed NVMe/SSD storage

  • 16-core / 32-thread machine

  • SQL Server Enterprise/Standard


📦 Data Volume

  • 1,000,000,000,000 rows × 16 bytes = 16,000,000,000,000 bytes = 16 TB of raw data

  • Add some log overhead + metadata: real insert size might be ~18–20 TB on disk


⚙️ Insertion Speed Estimates (With 4 Columns)

🚀 Optimized Scenario (Parallel Bulk Insert)

  • Use 32 threads, each inserting via SqlBulkCopy or BULK INSERT in parallel

  • Row rate per thread: ~100,000–150,000 rows/sec

  • Total row rate: 3.2M–4.8M rows/sec

📆 Time to Insert:

									
 
1T rows ÷ 4M rows/sec = 250,000 seconds ≈ 69 hours ≈ 2.9 days

⚖️ Realistic Scenario (Not Fully Optimized)

  • 1M–2M rows/sec total throughput

  • Could be bottlenecked by:

    • Disk write I/O

    • Transaction log throughput

    • Memory pressure / TempDB contention

⏱️ Time to Insert:

									
 
1T rows ÷ 1.5M rows/sec ≈ 666,667 seconds ≈ 7.7 days

🐢 Poorly Optimized Scenario (Row-by-Row Insert, Indexes Present)

  • Row-by-row inserts via T-SQL INSERT INTO

  • Logging, indexing, and checkpoint pressure

  • Estimated throughput: 10K–100K rows/sec

⏱️ Time to Insert:

									
 
At 100K rows/sec = 1T ÷ 100K = 10M seconds115 daysAt 10K rows/sec = 1T ÷ 10K = 100M seconds3.2 years

🧠 Summary Table

Scenario Insert Method Rows/sec Estimate Time to Insert 1T Rows
🚀 Fully optimized Parallel bulk 4M ~2.9 days
⚖️ Moderately optimized Bulk, some limits 1.5M ~7.7 days
🐢 Poorly optimized Row-by-row insert 10K–100K Months to years

✅ Best Practices for Fast Insertion (Even for 4-column Tables)

  1. Use SqlBulkCopy, BULK INSERT, or bcp

  2. Partition the target table, insert into each partition in parallel

  3. Minimal logging (Simple recovery mode + TABLOCK)

  4. Batch sizes of 10K–100K rows per insert

  5. Drop all indexes and constraints before loading

  6. Load into staging table, then index or merge as needed


Want me to help you build a script that does this efficiently? Or simulate timing on your hardware profile?

 
You said:
how do i make sql run faster to process this insert
 
ChatGPT said:

To make SQL Server run as fast as possible when inserting massive volumes of data (like 1 trillion rows), you need to minimize overhead, maximize parallelism, and optimize for throughput over transactional integrity (if acceptable for your use case).

Here’s a practical checklist you can follow to get maximum performance for inserts:


✅ 1. Use Bulk Insert Methods

These are 10–100x faster than INSERT INTO statements.

Use:

Tips:

  • Use large batch sizes (e.g. 50,000–100,000 rows per batch)

  • Use TABLOCK to enable minimal logging

  • Load from flat file or stream


✅ 2. Minimize Logging

SQL Server logs every insert unless you tell it not to.

Do this:

  • Set recovery model to SIMPLE or BULK_LOGGED:

    											
     
    ALTER DATABASE YourDB SET RECOVERY SIMPLE;
  • Use TABLOCK hint during bulk insert:

    											
     
    BULK INSERT your_tableFROM 'file_path'WITH (TABLOCK, BATCHSIZE = 100000, ROWS_PER_BATCH = 100000, DATAFILETYPE = 'native');

✅ 3. Remove Indexes and Constraints

Indexes slow down inserts by forcing SQL Server to maintain them as it writes.

Drop these before loading:

  • Indexes

  • Foreign keys

  • Default constraints

  • Triggers

After inserting, recreate indexes using CREATE INDEX WITH (ONLINE = ON, SORT_IN_TEMPDB = ON)


✅ 4. Use a Heap Table (No Clustered Index)

Clustered indexes are slower to insert into due to page splits and order maintenance.

									
 
CREATE TABLE your_table ( col1 INT, col2 INT, col3 INT, col4 INT) WITH (HEAP);

✅ 5. Maximize Parallelism

Use your 16-core / 32-thread CPU!

Strategies:

  • Break source data into N chunks and insert in parallel tasks

  • Use multiple BULK INSERT sessions concurrently

  • Partition your table (e.g., on a logical ID range)

Example (8 parallel processes):

									
 
start bulk_insert_part1.bat start bulk_insert_part2.bat ...

✅ 6. Use Fast Storage

Insert throughput is often I/O-bound.

  • Use NVMe SSDs or RAID 10 arrays

  • Place DATA, LOG, and TEMPDB on separate drives

  • Ensure TEMPDB has multiple data files (1 per 4 cores is a good rule)

									
 
-- Check tempdb usageSELECT * FROM sys.dm_io_virtual_file_stats(DB_ID(N'tempdb'), NULL);

✅ 7. Optimize TEMPDB

TEMPDB often becomes a bottleneck.

  • Pre-size TEMPDB to avoid autogrowth

  • Use multiple equally sized files (start with 8 for 16 cores)

									
 
-- Example: 8 tempdb filesALTER DATABASE tempdb ADD FILE ( NAME = tempdev2, FILENAME = 'D:\SQLData\tempdb2.ndf', SIZE = 512MB, FILEGROWTH = 512MB );-- Repeat for tempdev3...tempdev8

✅ 8. Disable Autogrowth

Autogrowth during a large load is a performance killer.

  • Pre-size your database and log files to hold at least 2x the expected data

  • Disable or control autogrowth using large increments (e.g., 1GB)


✅ 9. Staging Table + Switch

  • Insert into a staging table (heap, no indexes)

  • Once done, switch partition into your main table (very fast, metadata-only operation)


✅ 10. Monitor and Tune While Loading

Use DMVs to check for bottlenecks:

									
 
-- Wait statsSELECT * FROM sys.dm_os_wait_stats ORDER BY wait_time_ms DESC;-- Active queriesSELECT * FROM sys.dm_exec_requests;-- CPU and disk activitySELECT * FROM sys.dm_io_virtual_file_stats(NULL, NULL);

⚠️ Optional but Advanced:

  • Use table partitioning if you're loading data by time, ID ranges, etc.

  • Consider Columnstore indexes after loading for massive read performance gains.


Summary: Top Boosters

Optimization Estimated Speed Gain
Bulk insert (vs row-by-row) 10–100×
Minimal logging (TABLOCK) 2–10×
Dropping indexes 3–10×
Parallel inserts (multi-thread) 2–16× (depending on I/O)
SSD/NVMe vs HDD 3–20×

If you want, I can generate a parallel bulk insert script tailored to your system and data structure. Just let me know the data format (CSV, binary, etc.) and where it's coming from.

 
You said:
how do I do parallel inserts in the same query?
 
ChatGPT said:

Great question — in SQL Server, you cannot do truly parallel inserts in the same SQL query, because T-SQL is not inherently parallel for DML operations (like INSERT) across rows. However, there are workarounds that achieve parallelism by:

  • Splitting the data set

  • Running multiple inserts concurrently

  • Or leveraging T-SQL tricks with SELECT INTO + UNION ALL


🚫 Why You Can't Just INSERT in Parallel in One Query

SQL Server doesn’t parallelize inserts automatically unless certain conditions are met. Even then:

  • Inserts into tables with indexes or triggers force single-threaded execution

  • Parallel plans are read-parallel, not write-parallel


✅ Solutions for Achieving Parallel Inserts

🧠 1. Run Inserts in Parallel from Outside SQL Server (Recommended)

Use multiple clients, threads, or PowerShell jobs to insert data in parallel:

									
 
# PowerShell example - 4 parallel inserts 1..4 | ForEach-Object -Parallel { Invoke-Sqlcmd -Query "BULK INSERT your_table FROM 'file_part$_.csv' WITH (...)" -ServerInstance "your_server" }

Or from C#/Python:

									
 
Parallel.For(0, 4, i => { // Each thread runs SqlBulkCopy or INSERT ... SELECT});

⚙️ 2. Partition Your Source and Insert in Batches

Break your source into ID or row ranges.

									
 
-- Batch insert for IDs 1–250MINSERT INTO your_tableSELECT * FROM source_table WHERE id BETWEEN 1 AND 250000000;-- Do similar inserts in parallel (in app or SQL Agent jobs)

🔄 3. Use INSERT INTO ... SELECT + UNION ALL to Simulate Parallelism

SQL Server can sometimes parallelize the SELECT side, not the INSERT. You may get better performance with:

									
 
INSERT INTO your_table (col1, col2, col3, col4)SELECT * FROM( SELECT col1, col2, col3, col4 FROM source WHERE id BETWEEN 1 AND 250000000 UNION ALL SELECT col1, col2, col3, col4 FROM source WHERE id BETWEEN 250000001 AND 500000000 UNION ALL SELECT col1, col2, col3, col4 FROM source WHERE id BETWEEN 500000001 AND 750000000 UNION ALL SELECT col1, col2, col3, col4 FROM source WHERE id BETWEEN 750000001 AND 1000000000) AS all_data;

➡️ SQL Server may parallelize the SELECT side, allowing better use of cores.


🧱 4. Use Partitioned Table + Switch-in

If you're inserting massive data, you can:

  1. Create staging tables (1 per partition)

  2. Insert into them concurrently

  3. ALTER TABLE SWITCH them into the final table (very fast metadata operation)


🔧 5. Use Parallel BULK INSERT

If data is in files (CSV, native, etc.), split it into multiple files and run multiple BULK INSERT statements at the same time from your app or a script:

									
 
BULK INSERT your_table FROM 'data_part1.csv' WITH (TABLOCK, BATCHSIZE = 100000); BULK INSERT your_table FROM 'data_part2.csv' WITH (TABLOCK, BATCHSIZE = 100000);-- Run these in parallel processes

⚠️ Bonus Tip: Force Parallelism (Sometimes)

If SQL Server is refusing to parallelize your query, you can try:

									
 
OPTION (MAXDOP 8) -- Limit or encourage parallelism

But remember, INSERTs themselves aren't parallelized, only the read part might be.


🧠 Summary

Method Parallel? Where to Parallelize Speed Gain
App-level threading (e.g. C#/Python) Outside SQL Server ⭐⭐⭐⭐⭐
Multiple INSERT INTO ... SELECT ✅* Partially inside SQL ⭐⭐⭐
BULK INSERT from multiple files External script / app ⭐⭐⭐⭐
SELECT ... UNION ALL ⚠️ Maybe SELECT only (not insert) ⭐⭐
Table partitioning + SWITCH Parallel staging tables ⭐⭐⭐⭐

Would you like a ready-made parallel insert script or Python/C# app that loads data into SQL Server efficiently?

 
yes please
 
ChatGPT said:

Perfect 👍 — let’s build a parallel insert loader for SQL Server.

Below are two complete working options — one in PowerShell (very easy to run on Windows), and one in Python (great for scaling or automation).
Both will use all your CPU cores to insert into SQL Server in parallel, splitting the work into chunks.


⚙️ Option 1: PowerShell Parallel Bulk Insert (Recommended on Windows)

🧾 What it does

  • Spawns multiple background jobs (one per CPU core or file).

  • Each job runs a BULK INSERT for a specific data range or file.

  • Uses SQL Server authentication or Windows Integrated login.

🧠 Example Script

Save this as parallel_insert.ps1 and run it in PowerShell.

									
 
# CONFIGURATION $server = "localhost" $database = "MyDatabase" $table = "MyTargetTable" $filePathTemplate = "C:\data\data_part{0}.csv" # Files like data_part1.csv, data_part2.csv, etc. $fileCount = 8 # Number of files / threads $batchSize = 100000 # Function to bulk insert each file function Start-BulkInsertJob($i) { $query = @" BULK INSERT $table FROM '$(($filePathTemplate -f $i))' WITH ( FORMAT = 'CSV', FIRSTROW = 2, TABLOCK, FIELDTERMINATOR = ',', ROWTERMINATOR = '\n', BATCHSIZE = $batchSize ); "@ Write-Host "Starting bulk insert for file $i..." Invoke-Sqlcmd -ServerInstance $server -Database $database -Query $query Write-Host "Completed file $i" } # Run inserts in parallel $jobs = @() for ($i = 1; $i -le $fileCount; $i++) { $jobs += Start-Job -ScriptBlock ${function:Start-BulkInsertJob} -ArgumentList $i } # Wait for all jobs to complete Write-Host "Waiting for all inserts to complete..." $jobs | Wait-Job | Receive-Job Write-Host "✅ All parallel inserts completed."

🧱 Requirements

  • PowerShell 5+ or PowerShell Core

  • SQL Server PowerShell module:

    											
     
    Install-Module SqlServer
  • Your SQL Server must have BULK INSERT permission and TABLOCK enabled on target table.


🐍 Option 2: Python Parallel Loader (Using ThreadPoolExecutor)

🧾 What it does

  • Uses 8 parallel threads.

  • Each thread executes a bulk INSERT INTO ... SELECT or BULK INSERT.

  • Highly tunable for your system.

🧠 Example Script

Save this as parallel_insert.py:

									
 
import pyodbcfrom concurrent.futures import ThreadPoolExecutor, as_completed# CONFIGserver = 'localhost'database = 'MyDatabase'table = 'MyTargetTable'file_template = r'C:\data\data_part{}.csv'threads = 8batchsize = 100000conn_str = f"DRIVER={{ODBC Driver 17 for SQL Server}};SERVER={server};DATABASE={database};Trusted_Connection=yes;"def bulk_insert(file_index): conn = pyodbc.connect(conn_str, autocommit=True) cursor = conn.cursor() sql = f""" BULK INSERT {table} FROM '{file_template.format(file_index)}' WITH ( FORMAT = 'CSV', FIRSTROW = 2, TABLOCK, FIELDTERMINATOR = ',', ROWTERMINATOR = '\\n', BATCHSIZE = {batchsize} ); """ print(f"Starting file {file_index}...") cursor.execute(sql) print(f"✅ Completed file {file_index}") conn.close()# Run in parallelwith ThreadPoolExecutor(max_workers=threads) as executor: futures = [executor.submit(bulk_insert, i) for i in range(1, threads + 1)] for f in as_completed(futures): f.result()print("🎉 All parallel inserts completed successfully!")

🧱 Requirements

  • Python 3.8+

  • ODBC Driver 17 for SQL Server

  • Install packages:

    											
     
    pip install pyodbc

⚡ Performance Notes

  • Split your source data into N smaller files (one per thread or CPU core).

  • Each file should contain about the same number of rows.

  • Use TABLOCK and SIMPLE recovery mode to enable minimal logging.

  • Place files on separate disks if possible to improve I/O parallelism.

  • You can adjust $fileCount or threads to match your available cores (e.g., 16–32).


Would you like me to tailor this to your specific data format (e.g., CSV from a generator or an existing table in SQL Server)?
If you tell me:

  • Source type (table, file, or generated data)

  • Destination table name and schema

…I can generate the exact version of the script ready for your environment.


 
 

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