BYOPI - Design your own custom private AI Search indexer with no code ADF (SQLServer on private VM)
Executive Summary Building a fully private search indexing solution using Azure Data Factory (ADF) to sync SQL Server data from private VM to Azure AI Search is achievable but comes with notable complexities and limitations. This blog shares my journey, discoveries, and honest assessment of the BYOPI (Build Your Own Private Indexer) architecture. Architectural flow: Table of Contents Overall Setup How ADF works in this approach with Azure AI Search Challenges - discovered Pros and Cons: An Honest Assessment Conclusion and Recommendations 1. Overall Setup: Phase 1: Resource Group & Network Setup : create resource group and vNET (virtual network) in any region of your choice Phase 2: Deploy SQL Server VM: Phase 3: Create Azure Services - ADF (Azure Data Factory), Azure AI Search and AKV (Azure Key Vault) service from portal or from your choice of deployment. Phase 4: Create Private Endpoints for all the services in their dedicated subnets: Phase 5: Configure SQL Server on VM : connect to VM via bastion and setup database, tables & SP: Sample metadata used as below: CREATE DATABASE BYOPI_DB; GO USE BYOPI_DB; GO CREATE TABLE Products ( ProductId INT IDENTITY(1,1) PRIMARY KEY, ProductName NVARCHAR(200) NOT NULL, Description NVARCHAR(MAX), Category NVARCHAR(100), Price DECIMAL(10,2), InStock BIT DEFAULT 1, Tags NVARCHAR(500), IsDeleted BIT DEFAULT 0, CreatedDate DATETIME DEFAULT GETDATE(), ModifiedDate DATETIME DEFAULT GETDATE() ); CREATE TABLE WatermarkTable ( TableName NVARCHAR(100) PRIMARY KEY, WatermarkValue DATETIME ); INSERT INTO WatermarkTable VALUES ('Products', '2024-01-01'); CREATE PROCEDURE sp_update_watermark @TableName NVARCHAR(100), @NewWatermark DATETIME AS BEGIN UPDATE WatermarkTable SET WatermarkValue = @NewWatermark WHERE TableName = @TableName; END; INSERT INTO Products (ProductName, Description, Category, Price, Tags) VALUES ('Laptop Pro', 'High-end laptop', 'Electronics', 1299.99, 'laptop,computer'), ('Office Desk', 'Adjustable desk', 'Furniture', 599.99, 'desk,office'), ('Wireless Mouse', 'Bluetooth mouse', 'Electronics', 29.99, 'mouse,wireless'); Phase 6: Install Self-Hosted Integration Runtime Create SHIR in ADF: Go to ADF resource in Azure Portal Click "Open Azure Data Factory Studio" Note: You need to access from a VM in the same VNet or via VPN since ADF is private In ADF Studio, click Manage (toolbox icon) Select Integration runtimes → "+ New" Select "Azure, Self-Hosted" → "Self-Hosted" Name: SHIR-BYOPI or of your choice Click "Create" Copy Key1 (save it) Install SHIR on VM In the VM (via Bastion): Open browser, go to: https://www.microsoft.com/download/details.aspx?id=39717 Download and install Integration Runtime During setup: Launch Configuration Manager Paste the Key1 from Step 14 Click "Register" Wait for "Connected" status Phase 7: Create Search Index through below powershell script and saving it as search_index.ps1 $searchService = "search-byopi" $apiKey = "YOUR-ADMIN-KEY" $headers = @{ 'api-key' = $apiKey 'Content-Type' = 'application/json' } $index = @{ name = "products-index" fields = @( @{name="id"; type="Edm.String"; key=$true} @{name="productName"; type="Edm.String"; searchable=$true} @{name="description"; type="Edm.String"; searchable=$true} @{name="category"; type="Edm.String"; filterable=$true; facetable=$true} @{name="price"; type="Edm.Double"; filterable=$true} @{name="inStock"; type="Edm.Boolean"; filterable=$true} @{name="tags"; type="Collection(Edm.String)"; searchable=$true} ) } | ConvertTo-Json -Depth 10 Invoke-RestMethod ` -Uri "https://$searchService.search.windows.net/indexes/products-index?api-version=2020-06-30" ` -Method PUT ` -Headers $headers ` -Body $index Phase 8: Configure AKV & ADF Components - Link AKV and ADF for secrets Create Key Vault Secrets Navigate to kv-byopi (created AKV resource) in Portal Go to "Access policies" Click "+ Create" Select permissions: Get, List for secrets Select principal: adf-byopi-private Create Go to "Secrets" → "+ Generate/Import": Name: sql-password, Value: <> Name: search-api-key, Value: Your search key Create Linked Services in ADF Access ADF Studio from the VM (since it's private): Key Vault Linked Service: Manage → Linked services → "+ New" Search "Azure Key Vault" Configure: Name: LS_KeyVault Azure Key Vault: kv-byopi Integration runtime: AutoResolveIntegrationRuntime Test connection → Create SQL Server Linked Service: "+ New" → "SQL Server" Configure: Name: LS_SqlServer Connect via: SHIR-BYOPI Server name: localhost Database: BYOPI_DB Authentication: SQL Authentication User: sqladmin Password: Select from Key Vault → LS_KeyVault → sql-password Test → Create Azure Search Linked Service: "+ New" → "Azure Search" Configure: Name: LS_AzureSearch URL: https://search-byopi.search.windows.net Connect via: SHIR-BYOPI - Important - use SHIR API Key: From Key Vault → LS_KeyVault → search-api-key Test → Create Phase 9: Create ADF Datasets and PipelineCreate Datasets SQL Products Dataset: Author → Datasets → "+" → "New dataset" Select "SQL Server" → Continue Select "Table" → Continue Properties: Name: DS_SQL_Products Linked service: LS_SqlServer Table: Select Products click OK Watermark Dataset: Repeat with: Name: DS_SQL_Watermark Table: WatermarkTable Search Dataset: "+" → "Azure Search" Properties: Name: DS_Search_Index Linked service: LS_AzureSearch Index name: products-index Create Pipeline Author → Pipelines → "+" → "Pipeline" Name: PL_BYOPI_Private From Activities → General, drag "Lookup" activity Configure Lookup 1: Name: LookupOldWatermark Settings: Source dataset: DS_SQL_Watermark Query: below sql SELECT WatermarkValue FROM WatermarkTable WHERE TableName='Products' - **First row only**: ✓ Add another Lookup: Name: LookupNewWatermark Query: below sql SELECT MAX(ModifiedDate) as NewWatermark FROM Products Add Copy Data activity: Name: CopyToSearchIndex Source: Dataset: DS_SQL_Products Query: sql SELECT CAST(ProductId AS NVARCHAR(50)) as id, ProductName as productName, Description as description, Category as category, Price as price, InStock as inStock, Tags as tags, CASE WHEN IsDeleted = 1 THEN 'delete' ELSE 'upload' END as [@search.action] FROM Products WHERE ModifiedDate > '@{activity('LookupOldWatermark').output.firstRow.WatermarkValue}' AND ModifiedDate <= '@{activity('LookupNewWatermark').output.firstRow.NewWatermark}' Sink: Dataset: DS_Search_Index Write behavior: Merge Batch size: 1000 Add Stored Procedure activity: Name: UpdateWatermark SQL Account: LS_SqlServer Stored procedure: sp_update_watermark Parameters: TableName: Products NewWatermark: @{activity('LookupNewWatermark').output.firstRow.NewWatermark} Connect activities with success conditions Phase 10: Test and Schedule Test Pipeline Click "Debug" in pipeline Monitor in Output panel Check for green checkmarks Create Trigger In pipeline, click "Add trigger" → "New/Edit" Click "+ New" Configure: Name: TR_Hourly Type: Schedule Recurrence: Every 1 Hour OK → Publish All Monitor Go to Monitor tab View Pipeline runs Check Trigger runs Your pipeline should look like this: Phase 11: Validation & Testing Verify Private Connectivity From the VM, run PowerShell: # Test DNS resolution (should return private IPs) nslookup adf-byopi-private.datafactory.azure.net # Should show private IP like : 10.0.2.x nslookup search-byopi.search.windows.net # Should show private IP like : 10.0.2.x nslookup kv-byopi.vault.azure.net # Should show private IP like : 10.0.2.x # Test Search $headers = @{ 'api-key' = 'YOUR-KEY' } Invoke-RestMethod -Uri "https://search-byopi.search.windows.net/indexes/products-index/docs?`$count=true&api-version=2020-06-30" -Headers $headers Test Data Sync (adding few records) and verify in search index: -- Add test record INSERT INTO Products (ProductName, Description, Category, Price, Tags) VALUES ('Test Product Private', 'Testing private pipeline', 'Test', 199.99, 'test,private'); -- Trigger pipeline manually or wait for schedule -- Then verify in Search index 2. How ADF works in this approach with Azure AI search: Azure AI Search uses a REST API for indexing or called as uploading. When ADF sink uploads data to AI Search, it's actually making HTTP POST requests: for example - POST https://search-byopi.search.windows.net/indexes/products-index/docs/index?api-version=2020-06-30 Content-Type: application/json api-key: YOUR-ADMIN-KEY { "value": [ { "@search.action": "upload", "id": "1", "productName": "Laptop", "price": 999.99 }, { "@search.action": "delete", "id": "2" } ] } Delete action used here is soft delete and not hard delete. pipeline query: SELECT CAST(ProductId AS NVARCHAR(50)) as id, -- Renamed to match index field ProductName as productName, -- Renamed to match index field Description as description, Category as category, Price as price, InStock as inStock, Tags as tags, CASE WHEN IsDeleted = 1 THEN 'delete' ELSE 'upload' END as [@search.action] -- Special field with @ prefix FROM Products WHERE ModifiedDate > '2024-01-01' ``` Returns this resultset: ``` id | productName | description | category | price | inStock | tags | @search.action ----|----------------|------------------|-------------|--------|---------|----------------|--------------- 1 | Laptop Pro | High-end laptop | Electronics | 1299 | 1 | laptop,computer| upload 2 | Office Chair | Ergonomic chair | Furniture | 399 | 1 | chair,office | upload 3 | Deleted Item | Old product | Archive | 0 | 0 | old | delete The @search.action Field - The Magic Control This special field tells Azure AI Search what to do with each document: @search.action What It Does When to Use What Happens If Document... upload Insert OR Update Most common - upsert operation Exists: Updates it<br>Doesn't exist: Creates it merge Update only When you know it exists Exists: Updates specified fields<br>Doesn't exist: ERROR mergeOrUpload Update OR Insert Safe update Exists: Updates fields<br>Doesn't exist: Creates it delete Remove from index To remove documents Exists: Deletes it<br>Doesn't exist: Ignores (no error) ADF automatically converts SQL results to JSON format required by Azure Search: { "value": [ { "@search.action": "upload", "id": "1", "productName": "Laptop Pro", "description": "High-end laptop", "category": "Electronics", "price": 1299.00, "inStock": true, "tags": "laptop,computer" }, { "@search.action": "upload", "id": "2", "productName": "Office Chair", "description": "Ergonomic chair", "category": "Furniture", "price": 399.00, "inStock": true, "tags": "chair,office" }, { "@search.action": "delete", "id": "3" // For delete, only ID is needed } ] } ADF doesn't send all records at once. It batches them based on writeBatchSize and each batch is a separate HTTP POST to Azure Search How ADF will detect new changes and run batches: Watermark will be updated after each successful ADF run to detect new changes as below: Handling different scenarios: Scenario 1: No Changes Between Runs: Run at 10:00 AM: - Old Watermark: 09:45:00 - New Watermark: 10:00:00 - Query: WHERE ModifiedDate > '09:45' AND <= '10:00' - Result: 0 rows - Action: Still update watermark to 10:00 - Why: Prevents reprocessing if changes come later Scenario 2: Bulk Insert Happens: Someone inserts 5000 records at 10:05 AM Run at 10:15 AM: - Old Watermark: 10:00:00 - New Watermark: 10:15:00 - Query: WHERE ModifiedDate > '10:00' AND <= '10:15' - Result: 5000 rows - Action: Process all 5000, update watermark to 10:15 Scenario 3: Pipeline Fails Run at 10:30 AM: - Old Watermark: 10:15:00 (unchanged from last success) - Pipeline fails during Copy activity - Watermark NOT updated (still 10:15:00) Next Run at 10:45 AM: - Old Watermark: 10:15:00 (still the last successful) - New Watermark: 10:45:00 - Query: WHERE ModifiedDate > '10:15' AND <= '10:45' - Result: Gets ALL changes from 10:15 to 10:45 (30 minutes of data) - No data loss! Note: There is still room for improvement by refining this logic to handle more advanced scenarios. However, I have not examined the logic in depth, as the goal here is to review how the overall setup functions, identify its limitations, and compare it with the indexing solutions available in AI Search. 3. Challenges - disovered: When I tried to set out to build a private search indexer for SQL Server data residing on an Azure VM with no public IP, the solution seemed straightforward: use Azure Data Factory to orchestrate the data movement to Azure AI Search. The materials made it sound simple. The reality? It's possible, but the devil is in the details. What We Needed: ✅ SQL Server on private VM (no public IP) ✅ Azure AI Search with private endpoint ✅ No data over public internet ✅ Support for full CRUD operations ✅ Near real-time synchronization ✅ No-code/low-code solution Reality Check: ⚠️ DELETE operations not natively supported in ADF sink ⚠️ Complex networking requirements ⚠️ Higher costs than expected ⚠️ Significant setup complexity ✅ But it IS possible with workarounds Components Required Azure VM: ~$150/month (D4s_v3) Self-Hosted Integration Runtime: Free (runs on VM) Private Endpoints: ~$30/month (approx 3 endpoints) Azure Data Factory: ~$15-60/month (depends on frequency) Azure AI Search: ~$75/month (Basic tier) Total: ~$270-315/month** The DELETE Challenge: Despite Azure AI Search REST API fully supporting delete operations via @search.action, ADF's native Azure Search sink does NOT support delete operations. -- This SQL query with delete action SELECT ProductId as id, CASE WHEN IsDeleted = 1 THEN 'delete' ELSE 'upload' END as [@search.action] FROM Products -- Will NOT delete documents in Azure Search when using Copy activity -- The @search.action = 'delete' is ignored by ADF sink! Nevertheless, there is a workaround using the Web Activity approach or by calling the REST API from the ADF side to perform the delete operation. { "name": "DeleteViaREST", "type": "Web", "typeProperties": { "url": "https://search.windows.net/indexes/index/docs/index", "method": "POST", "body": { "value": [ {"@search.action": "delete", "id": "123"} ] } } } Development Challenges No Direct Portal Access: With ADF private, you need: Jump box in the same VNet VPN connection Bastion for access Testing Complexity: Can't use Postman from local machine Need to test from within VNet Debugging requires multiple tools 4. Pros and Cons: An Honest Assessment: Pros: Security: Complete network isolation Compliance: Meets strict requirements No-Code: Mostly configuration-based Scalability: Can handle large datasets Monitoring: Built-in ADF monitoring Managed Service: Microsoft handles updates Cons: DELETE Complexity: Not natively supported Cost: Higher than expected Setup Complexity: Many moving parts Debugging: Difficult with private endpoints Hidden Gotchas: - SHIR requires Windows VM (Linux in preview) - Private endpoint DNS propagation delays - ADF Studio timeout with private endpoints - SHIR auto-update can break pipelines 5. Conclusion and Recommendations: When to Use BYOPI: ✅ Good Fit: Strict security requirements Needs indexing from an un-supported scenarios for example SQL server residing on private VM Budget > $500/month Team familiar with Azure networking Read-heavy workloads ❌ Poor Fit: Simple search requirements Budget conscious Need real-time updates Heavy DELETE operations Small team without Azure expertise BYOPI works, but it's more complex and expensive than initially expected. The lack of native DELETE support in ADF sink is a significant limitation that requires workarounds. Key Takeaways It works but requires significant effort DELETE (hard) operations need workarounds Costs will be higher than expected Complexity is substantial for a "no-code" solution Alternative solutions might be better for many scenarios Disclaimer: The sample scripts provided in this article are provided AS IS without warranty of any kind. The author is not responsible for any issues, damages, or problems that may arise from using these scripts. Users should thoroughly test any implementation in their environment before deploying to production. Azure services and APIs may change over time, which could affect the functionality of the provided scripts. Always refer to the latest Azure documentation for the most up-to-date information. Thanks for reading this blog! I hope you've found this approach of creating own private indexing solution for Azure AI Search (BYOPI) useful 😀Using ADF Data Flow Derived Column transform against nested Delta structures
I'm trying to use a derived column transform within an ADF Data Flow where I've ingested a Delta table with nested structures. I'm struggling with the syntax needed to flatten out these structures and no column info is displayed despite me being able to preview the data. Such a structure would be: { "ContactId":"1002657", "Name":{ "FirstName":"Donna", "FullName":"Donna Brittain", "LastName":"Brittain" } } Data Preview working OK: The structure of my Delta table: The error I'm getting trying to reference a nested column: How can I reference a nested column such as Name.FirstName to flatten it out to FirstName and why is it not showing up in any of the mappings?
