This is the legacy 4D documentation web site. Documentations are progressively being moved to developer.4d.com
- 4D Language Reference
-
- Introduction
- Language Definition
- Debugging
- 4D Environment
- Arrays
- Backup
- BLOB
- Boolean
- Cache Management
- Collections
- Communications
- Compiler
- Data Entry
- Data Security
- Database Methods
- Date and Time
- Design Object Access
- Drag and Drop
- Entry Control
- File and Folder
- Form Events
- Forms
- Formulas
- Graphs
- Hierarchical Lists
- HTTP
- Import and Export
- Interruptions
- JSON
- Language
- LDAP
- Licenses
- List Box
- Math
- Menus
- Messages
- Named Selections
- Objects (Forms)
- Objects (Language)
- On a Series
- Operators
- ORDA - DataClass
- ORDA - DataClassAttribute
- ORDA - DataStore
- ORDA - Entity
- ORDA - EntitySelection
- Pasteboard
- PHP
- Pictures
- Printing
- Process (Communications)
- Process (User Interface)
- Processes
- Queries
- Quick Report
- Record Locking
- Records
- Relations
- Resources
- Secured Protocol
- Selection
- Sets
- Spell Checker
- SQL
- String
- Structure Access
- Styled Text
- Subrecords
- SVG
- System Documents
- System Environment
- Table
- Tools
- Transactions
- Triggers
- User Interface
- Users and Groups
- Variables
- Web Area
- Web Server
- Web Services (Client)
- Web Services (Server)
- Windows
- XML
- XML DOM
- XML SAX
- List of constant themes
- Error Codes
- Character Codes
- Deprecated Commands
Cache Management
4D integrates a built-in data cache scheme for accelerating I/O operations. The fact that data modifications are, for some time, present in the data cache and not on the disk is transparent to your coding. For example, if you issue a QUERY call, the 4D database engine integrates the data cache in the query operation.
The database cache manager has been fully rewritten in 4D v16, allowing it to take advantage of 64-bit environments. Automatically enabled and optimized, it can however be dynamically configured or analyzed with the commands from this theme. In addition, a customizable priority system is implemented. For more information, please refer to the Managing priorities in database cache section.
Note also that a Cache flush periodicity selector can be used with the SET DATABASE PARAMETER and Get database parameter commands.
Product: 4D
Theme: Cache Management
Created: 4D v16
4D Language Reference ( 4D v20 R7)
