C PL/SQL Program Limits. Oracle 10g Release 2

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PL/SQL Program Limits

This appendix discusses the program limits that are imposed by the PL/SQL language. PL/SQL is based on the programming language Ada. As a result, PL/SQL uses a variant of Descriptive Intermediate Attributed Notation for Ada (DIANA), a tree-structured intermediate language. It is defined using a meta-notation called

Interface Definition Language (IDL). DIANA is used internally by compilers and other tools.

At compile time, PL/SQL source code is translated into machine-readable m-code.

Both the DIANA and m-code for a procedure or package are stored in the database. At run time, they are loaded into the shared memory pool. The DIANA is used to compile dependent procedures; the m-code is simply executed.

In the shared memory pool, a package spec, object type spec, standalone subprogram, or anonymous block is limited to 67108864 (2**26) DIANA nodes which correspond to tokens such as identifiers, keywords, operators, and so on. This allows for ~6,000,000 lines of code unless you exceed limits imposed by the PL/SQL compiler, some of

which are given in Table C–1 .

Table C–1 PL/SQL Compiler Limits

Item

bind variables passed to a program unit exception handlers in a program unit fields in a record levels of block nesting levels of record nesting levels of subquery nesting levels of label nesting levels of nested collections magnitude of a

BINARY_INTEGER

value magnitude of a

PLS_INTEGER

value number of formal parameters in an explicit cursor, function, or procedure objects referenced by a program unit precision of a

FLOAT

value (binary digits) precision of a

NUMBER

value (decimal digits) precision of a

REAL

value (binary digits)

Limit

32768

65536

255

254

98 no predefined limit

-2147483648..2147483647

65536

126

PL/SQL Program Limits

C-1

Table C–1 (Cont.) PL/SQL Compiler Limits

Item

size of an identifier (characters) size of a string literal (bytes) size of a

CHAR

value (bytes) size of a

LONG

value (bytes) size of a

LONG RAW

value (bytes) size of a

RAW

value (bytes) size of a

VARCHAR2

value (bytes) size of an

NCHAR

value (bytes) size of an

NVARCHAR2

value (bytes) size of a

BFILE

value (bytes) size of a

BLOB

value (bytes) size of a

CLOB

value (bytes) size of an

NCLOB

value (bytes)

Limit

32767

32760

32767

4G * value of DB_BLOCK_SIZE parameter

To estimate how much memory a program unit requires, you can query the data dictionary view user_object_size

. The column parsed_size

returns the size (in bytes) of the "flattened" DIANA. For example:

SQL> SELECT * FROM user_object_size WHERE name = 'PKG1';

NAME TYPE SOURCE_SIZE PARSED_SIZE CODE_SIZE ERROR_SIZE

----------------------------------------------------------------

PKG1 PACKAGE 46 165 119 0

PKG1 PACKAGE BODY 82 0 139 0

Unfortunately, you cannot estimate the number of DIANA nodes from the parsed size.

Two program units with the same parsed size might require 1500 and 2000 DIANA nodes, respectively because, for example, the second unit contains more complex SQL statements.

When a PL/SQL block, subprogram, package, or object type exceeds a size limit, you get an error such as

PLS-00123: program too large

. Typically, this problem occurs with packages or anonymous blocks. With a package, the best solution is to divide it into smaller packages. With an anonymous block, the best solution is to redefine it as a group of subprograms, which can be stored in the database.

For additional information about the limits on datatypes, see

Chapter 3, "PL/SQL

Datatypes" . For limits on collection subscripts, see

"Referencing Collection Elements" on page 5-11.

C-2

Oracle Database PL/SQL User’s Guide and Reference