SharePoint Server stores configuration, content and service-application data in SQL Server databases. SharePoint Online also uses Microsoft-managed storage behind the service, but customers do not receive SQL access and should manage tenant content through SharePoint, Microsoft Graph, supported APIs and admin tools.
That distinction matters. Advice about rebuilding indexes or querying SharePoint tables may be relevant to an on-premises farm administrator, but it is not a SharePoint Online tuning technique.
SharePoint Server: what SQL holds
A SharePoint Server farm depends on several database types.
- The configuration database stores farm configuration.
- The Central Administration content database supports the administration site.
- Content databases store site collections and their content.
- Service applications such as Search, Managed Metadata and User Profile use their own databases.
The precise set depends on the SharePoint Server edition, topology and enabled services. Microsoft's database types and descriptions are the safer reference than memorising old internal table names.
Files uploaded to a normal document library are represented in a content database along with list data, metadata, security and version information. Remote BLOB Storage can change where binary content is held in supported SharePoint Server designs, but it does not turn the SharePoint object model into a direct SQL integration surface.
Do not query or modify SharePoint databases directly
The database schema is an implementation detail. Reading internal tables may produce misleading results because permissions, versions and product logic live above individual rows. Writing directly to those tables can leave the farm inconsistent and unsupported.
Use supported interfaces instead: SharePoint administration tools, SharePoint Management Shell, supported APIs, and migration or backup tools that explicitly support the SharePoint version.
If a reporting requirement appears to need SQL access, first define the business data required. A supported export, search query, API or reporting store is usually the maintainable design.
SharePoint Online: Microsoft owns the database tier
SharePoint Online is a service, not a hosted version of your own SharePoint farm. Tenant administrators manage sites, storage, permissions, retention and sharing, but not the underlying SQL Server configuration.
You cannot solve a slow SharePoint Online page by rebuilding a content-database index. Use service-appropriate evidence instead:
- run Page Diagnostics for SharePoint on a site page
- inspect web parts, requests, images and custom code
- check Microsoft 365 service health for incidents
- review list and library design
- reproduce the issue with an ordinary user and a clean browser session
Page Diagnostics is for pages, not system pages or library views. Its report identifies likely page-design problems; it does not expose Microsoft's database tier.
If you operate SharePoint Server
Treat database maintenance as a joint SharePoint and SQL Server responsibility.
- Confirm the exact supported SharePoint and SQL Server versions.
- Use Microsoft's capacity guidance for that product.
- Monitor storage, latency, database growth, backups and recovery.
- Test maintenance in a non-production environment.
- Take supported backups and prove restoration.
- Keep custom SQL jobs away from SharePoint databases unless Microsoft documents them.
Microsoft's current storage and SQL Server capacity guidance explicitly applies to SharePoint Server, not SharePoint in Microsoft 365.
Ask one question before following any “SharePoint SQL fix”: is this SharePoint Online or a SharePoint Server farm that we operate?
If it is Online, stay above the service boundary. If it is Server, confirm product support, take recoverable backups and use documented farm and SQL maintenance.
This article explains supported responsibility boundaries. It does not diagnose a particular farm, prove a performance cause or authorise a database change.
For help separating SharePoint Online administration from SharePoint Server operations, join the SharePoint & Teams Admins Space.