3.3.1 Estimating Memory Usage

The expression for calculating the amount of memory to be used by the CEP Server is shown below.

Estimated amount of memory required 
     = A + ((B + C + D + E + F) x numberOfCepEngines + G + H) x 1.2 + I

Table 3.1 Explanation of items in memory estimation expression
Item	Explanation	Memory usage
A	Base memory amount	2.7 GB
B	Amount of memory when using high-speed filter rules	Refer to "3.3.1.1 Amount of Memory when Using High-speed Filter Rules".
C	Amount of memory when master data is used by the high-speed filter	Refer to "3.3.1.2 Amount of Memory when Master Data is used by the High-speed Filter".
D	Amount of memory when rules are used in complex event processing	The estimation expression is shown below. (MB) numberOfRuleDefinitions x 31 MB
E	Amount of memory when an event type definition is used in complex event processing	The estimation expression is shown below. (MB) (numberOfInputEventTypes + numberOfTypesOfEventsAlreadyProcessedByHighSpeedFilter) x 37 MB
F	Amount of memory when a SOAP listener definition is used in complex event processing	The estimation expression is shown below. (MB) numberOfUserDevelopedWebServices x 2.5 MB
G	Amount of memory required for Terracotta collaboration	The estimation expression is shown below. (MB) sizeOfDataPoolInCache x numberOfCepEnginesToPerformTerracottaCollaboration Refer to "9.3.1 Terracotta Cache Configuration File" for the value of sizeOfDataPoolInCache.
H	Amount of memory required for RDB collaboration (using a cache)	The estimation expression is shown below. (MB) Memory requirement of CEP engines that perform RDB collaboration = (cacheRetentionPeriod + cachePurgeInterval) x numberOfRdbSearchesWithDifferentSearchConditionsPerSecond x averageNumberOfRecordsThatMatchSearchConditions x (totalSizeOfExtractColumn(bytes) + 15) x 13 / 1048576 Memory requirement of RDB collaboration = totalMemoryRequirementOfCepEnginesThatPerformRdbCollaboration
I	Amount of memory called from the custom listener and used by a user-developed Java class	Depends on the implementation of the user-developed Java class.

3.3.1.1 Amount of Memory when Using High-speed Filter Rules

The expression for calculating the amount of memory (bytes) when high-speed filter rules are used is shown below.

Amount of memory when using high-speed filter rules
    = Total amount of each ifThenStatementMemoryRequirement
 
ifThenStatementMemoryRequirement = 272 x 1024 x 1024 + 960 x 1024 x R + 16 x L + 8 x a

Variable	Meaning	Unit
R	Number of output items to be described in the output expressions of high-speed filter rules	Items
L	Maximum data size of input events	Bytes
a	Area to be used in partial character, character range, and numeric range search (*1)	Bytes

*1: Use the following expression to calculate this if search is to be executed with a partial character, character range, or numeric range specification:

numberOfPartialChars, charRange, or numericRange x numberOfKeywordChars x 2,048 Bytes

Use the following expression to calculate this if search is to be executed with a combination of partial character, character range, and numeric range specifications:

numberOfPartialChars x charRange x numericRange x numberOfKeywordChars x 2,048 Bytes

For "number of partial characters", specify the number of parts delimited by a vertical bar (|).
For example, if the search keyword "Sm(ith|ythe|ithy)John" is specified, the number of partial characters will be 3.
For "character range", specify how many are in the range of the ASCII character code values separated by a hyphen (-).
For example, if the search keyword "class[A-C]" is specified, that range will be 0x41 (A), 0x42 (B), and 0x43 (C), so the character range will be 3.
For "numeric range", specify how many are in the range of numeric 1 and numeric 2, separated by a comma (,).
For example, if the search keyword "alcohol[9,11]%" is specified, that range will be 9, 10, and 11, so the numeric range will be 3.

3.3.1.2 Amount of Memory when Master Data is used by the High-speed Filter

If master data is to be used, the amount of memory capacity shown below will be required in addition to what would be normally required.

Memory usage when using master data = Total amount of each ifThenStatementMemoryRequirement
 
ifThenStatementMemoryRequirement 
                    = outputItemMemoryRequirement + joinRelationalExpressionMemoryRequirement
 
outputItemMemoryRequirement = N x (B + 60)
 
(If a numeric-type or string-type perfect match is specified)
joinRelationalExpressionMemoryRequirement = N x (216 + A)
 
(If partial match of a string is specified)
joinRelationalExpressionMemoryRequirement = a x N x (2 x A - (log10N or 1, whichever is greater)) x 144

The meaning of each variable is shown below.

Variable	Meaning	Unit
N	Number of master data records	Records
A	Average data size of master items specified in search expressions or in join-relational expressions in join expressions (*1)	Bytes
B	Average data size of master items specified in the output items of output expressions (*1)	Bytes
a	Join key coefficient (*2)	0 < a < 1

*1: If the "val" function is specified in a join-relational expression and an output item, the data size will be 16.

*2: This depends on the content of the master data specified in the join conditions in the high-speed filter rules (see the table below).

Table 3.2 Join key coefficient
Content of master data	Join key coefficient
If values vary widely in the second half of the key Example: (000001, 000002, 000012, 000125, etc.)	0.4
If values vary widely in the first half of the key Example: (100-001, 210-001, 321-001, etc.)	0.6
If values vary widely throughout the key Example: (123456, 234512, 912384, etc.)	0.8