Init parameterMemory

USE_LARGE_PAGES

What it controls

Whether the SGA is placed in Linux HugePages.

Know this before you change it

ONLY refuses to start the instance unless the whole SGA fits in HugePages, so a misconfiguration is noticed at startup instead of as poor performance later.

Default: TRUE

Check and change it

1-- Current value on every instance2SELECT inst_id, name, value, isdefault, ismodified3FROM gv$parameter4WHERE name = 'use_large_pages';5 6-- Value stored in the spfile7SELECT sid, value FROM v$spparameter WHERE name = 'use_large_pages' AND isspecified = 'TRUE';8 9-- Static: saved in the spfile, takes effect after a restart10ALTER SYSTEM SET use_large_pages = ONLY SCOPE = SPFILE SID = '*';11 12-- Remove it from the spfile to go back to the default at the next restart13ALTER SYSTEM RESET use_large_pages SCOPE = SPFILE SID = '*';

Open in the parameter referenceOracle's reference

More in Memory

• MEMORY_TARGETTotal memory for SGA and PGA together under Automatic Memory Management.
• MEMORY_MAX_TARGETUpper limit for MEMORY_TARGET.
• SGA_TARGETSize of the SGA under Automatic Shared Memory Management. Oracle moves memory between the buffer cache, shared pool and other pools as load changes.
• SGA_MAX_SIZEThe most memory the SGA can grow to without a restart.
• PGA_AGGREGATE_TARGETTarget for the total private memory of all server processes, used for sorts, hash joins and bitmap operations.
• PGA_AGGREGATE_LIMITHard limit on total PGA (12c and later). Above it, Oracle ends the calls or sessions using the most PGA with ORA-04036.
• SHARED_POOL_SIZESize of the shared pool: parsed SQL, PL/SQL and the dictionary cache. Under SGA_TARGET it's a minimum.
• DB_CACHE_SIZESize of the default buffer cache. Under SGA_TARGET it's a minimum.
• INMEMORY_SIZESize of the In-Memory column store. On 12.2 and later it can be increased while the instance is running.