SQL Server 2000 (version 8.00.2039) is designed to aggressively acquire and retain memory for performance optimization. This behavior becomes problematic when memory isn't released after large query operations, leading to gradual memory consumption until Windows denies further allocations.

-- Check current memory usage in SQL Server 2000
DBCC MEMORYSTATUS
GO

For SQL Server 2000 SP4, these approaches can help reclaim memory without service interruption:

-- Clear procedure cache (releases compiled plans)
DBCC FREEPROCCACHE
GO

-- Clear all data from buffer cache
DBCC DROPCLEANBUFFERS
GO

-- Alternative method using undocumented command
DBCC FREESYSTEMCACHE('ALL')
GO

While not immediate solutions, these settings help manage memory growth:

-- Set max server memory (MB) - adjust value as needed
EXEC sp_configure 'show advanced options', 1
RECONFIGURE
EXEC sp_configure 'max server memory', 2048  -- Example: 2GB limit
RECONFIGURE
GO

-- Enable AWE if needed (for 32-bit systems with >4GB RAM)
EXEC sp_configure 'awe enabled', 1
RECONFIGURE
GO

Create a scheduled job that runs during off-peak hours:

-- Sample maintenance script
USE msdb
GO
EXEC sp_add_job @job_name = 'Memory_Cleanup'
EXEC sp_add_jobstep @job_name = 'Memory_Cleanup', 
                   @step_name = 'Clear_Caches',
                   @subsystem = 'TSQL',
                   @command = 'DBCC FREEPROCCACHE; DBCC DROPCLEANBUFFERS',
                   @database_name = 'master'
GO

Track memory usage patterns with these queries:

-- Buffer cache usage by database
SELECT COUNT(*)AS cached_pages_count,
       CAST(COUNT(*)*8/1024.0 AS DECIMAL(10,2)) AS cached_MB,
       CASE database_id 
         WHEN 32767 THEN 'ResourceDb' 
         ELSE DB_NAME(database_id) 
       END AS database_name
FROM sys.dm_os_buffer_descriptors
GROUP BY DB_NAME(database_id), database_id
ORDER BY cached_pages_count DESC
GO

-- Procedure cache memory usage
SELECT TOP 20
       CAST(SUM(size_in_bytes)/1024.0/1024.0 AS DECIMAL(10,2)) AS size_mb,
       cacheobjtype, objtype
FROM sys.dm_exec_cached_plans
GROUP BY cacheobjtype, objtype
ORDER BY size_mb DESC
GO

SQL Server 2000 (version 8.00.2039 SP4) has an aggressive memory allocation strategy where it tends to hold onto memory even after completing memory-intensive operations. This behavior is by design to optimize performance for subsequent queries.

The buffer pool in SQL Server 2000 maintains cached execution plans and data pages in memory. While this improves performance for repeated queries, it can lead to situations where Windows starves for memory. Unlike newer versions, SQL Server 2000 lacks sophisticated memory pressure detection.

For SQL Server 2000, you have several options to free up memory:

1. DBCC FREEPROCCACHE

-- Clears the procedure cache
DBCC FREEPROCCACHE
GO

2. DBCC DROPCLEANBUFFERS

-- Removes all clean buffers from the buffer pool
DBCC DROPCLEANBUFFERS
GO

3. Setting Max Server Memory

-- Set maximum memory SQL Server can use (in MB)
EXEC sp_configure 'max server memory', 2048
RECONFIGURE
GO

Create a scheduled job that runs during low-activity periods:

USE msdb
GO
EXEC sp_add_job @job_name = 'Memory_Cleanup'
EXEC sp_add_jobstep @job_name = 'Memory_Cleanup',
    @step_name = 'Free_Memory',
    @subsystem = 'TSQL',
    @command = 'DBCC FREEPROCCACHE; DBCC DROPCLEANBUFFERS',
    @database_name = 'master'
GO

• Executing these commands will cause temporary performance degradation
• DBCC FREEPROCCACHE forces recompilation of all execution plans
• Memory will naturally grow again as queries execute
• Consider upgrading to a newer SQL Server version with better memory management

Enable the "Lock pages in memory" privilege for SQL Server service account, which allows Windows to signal SQL Server when memory pressure occurs.