What causes ORA-04031?

Shared pool is too small for the number of concurrent sessions and SQL statements. Hard parsing of non-bind-variable SQL fragments the shared pool. Memory leak in a PL/SQL package. Large number of open cursors exhausting the shared pool. CLOB or LOB operations consuming excessive shared memory

How do I fix ORA-04031?

Step 1: Flush the shared pool (emergency): `ALTER SYSTEM FLUSH SHARED_POOL;`.. Step 2: Check current shared pool usage: `SELECT pool, bytes FROM v$sgastat WHERE pool = 'shared pool' ORDER BY bytes DESC;`.. Step 3: Increase shared pool size: `ALTER SYSTEM SET SHARED_POOL_SIZE = 500M;` or increase SGA_TARGET.. Step 4: Enable CURSOR_SHARING=FORCE or use bind variables in SQL to reduce hard parsing.. Step 5: Identify sessions with too many open cursors: `SELECT username, COUNT(*) FROM v$open_cursor GROUP BY username ORDER BY 2 DESC;`.

Critical severityperformance

Oracle Database Error:
ORA-04031

What does this error mean?

Oracle could not allocate the requested amount of shared memory in the SGA (System Global Area), typically because the shared pool is full.

Common causes

1Shared pool is too small for the number of concurrent sessions and SQL statements
2Hard parsing of non-bind-variable SQL fragments the shared pool
3Memory leak in a PL/SQL package
4Large number of open cursors exhausting the shared pool
5CLOB or LOB operations consuming excessive shared memory

How to fix it

1Step 1: Flush the shared pool (emergency): `ALTER SYSTEM FLUSH SHARED_POOL;`.
2Step 2: Check current shared pool usage: `SELECT pool, bytes FROM v$sgastat WHERE pool = 'shared pool' ORDER BY bytes DESC;`.
3Step 3: Increase shared pool size: `ALTER SYSTEM SET SHARED_POOL_SIZE = 500M;` or increase SGA_TARGET.
4Step 4: Enable CURSOR_SHARING=FORCE or use bind variables in SQL to reduce hard parsing.
5Step 5: Identify sessions with too many open cursors: `SELECT username, COUNT(*) FROM v$open_cursor GROUP BY username ORDER BY 2 DESC;`.

Example log output

ORA-04031: unable to allocate 65560 bytes of shared memory ("shared pool","unknown object","sga heap(1,0)","frame")

Frequently asked questions

Does flushing the shared pool cause performance issues?

Yes — flushing causes all SQL statements to be re-parsed and re-optimized (cold start). Use it only as an emergency measure and address the root cause (insufficient shared pool size or excessive hard parsing).

Source · docs.oracle.com/error-help/db/ora-04031