FarragoSystemParameters

From Eigenpedia

The table below defines the parameters that can be set with the ALTER SYSTEM command, e.g.

alter system set "cachePagesInit" = 1000;
alter system set "calcVirtualMachine" = 'CALCVM_AUTO';
alter system set "codeCacheMaxBytes" = max;

 
select * from sys_fem."Config"."FarragoConfig";
select * from sys_fem."Config"."FennelConfig";

(TODO: generate this automatically from the catalog UML, which is the primary definition of these parameters. Some obsolete parameters are left out below.)

Default values are provided for a standard Farrago developer build, but may vary according to personality-based packaging. Note that the fundamental units used (such as seconds and pages) are convenient for Farrago and Fennel but not necessarily for the user, so personalities may want to translate these into human-oriented units via system views and management procedures (e.g. multiplying number of pages by page size and converting to gigabytes).

Name	Domain	Default Value	Update Policy	Description
fennelDisabled	boolean	false	Takes effect on startup	Determines whether Fennel native code components are loaded when the system starts up.
codeCacheMaxBytes	64-bit integer (number of bytes, 0 for disabled, -1 for unlimited)	2000000	Immediate	Sets the size of the Farrago code cache, which is used for optimizer plan caching and SQL/MED data wrapper pooling. Setting to MAX causes the cache to grow without bound except for the JVM heap size. Setting to MIN disables the code cache, discarding any currently cached entries. Setting to a finite value causes LRU victimization according to rough estimates on per-object memory usage.
checkpointInterval	32-bit integer (seconds, 0 to disable timer-based checkpoints)	300	Takes effect on startup	Sets the interval between automatic timed checkpoints. Regardless of this setting, checkpoints may occur at other times as well (e.g. when the system detects that free log space is low, or when an administrator issues the explicit CHECKPOINT command).
serverRmiRegistryPort	32-bit integer, -1 for personality-based defaults	-1 (implies 5433 for default Farrago personality)	Takes effect on startup	Sets the port number on which to listen for RMI connections (this is the port number specified in client JDBC URL's).
serverSingleListenerPort	32-bit integer, -1 to disable	-1	Takes effect on startup	Sets a "single listener" port number for RMI. Normally, RMI opens additional ports for each remoted object, which can cause problems in firewalled configurations. Setting a port number here forces RMI to multiplex all non-connection requests through this port. If set, this must be a different value from serverRmiRegistryPort, and both ports must be accessible to clients (although the client never specifies this port number in the URL).
calcVirtualMachine	String, one of CALCVM_FENNEL, CALCVM_JAVA, or CALCVM_AUTO.	CALCVM_AUTO	Immediate	Controls which calculator virtual machine is used for evaluating SQL row expressions. CALCVM_FENNEL uses a virtual machine implemented inside of Fennel. CALCVM_JAVA generates and compiles Java code on the fly. CALCVM_AUTO allows the optimizer to choose a blend of the two calculators based on cost or other factors. Changing this parameter causes all entries to be discarded from the code cache.
cachePageSize	32-bit integer (number of bytes; must be a power of 2)	4096	Immutable after database creation.	Determines contiguous size of memory buffers allocated by cache. Also determines contiguous size of pages stored on disk; these are the elemental allocation units for all disk-based data structures such as indexes.
cachePagesMax	32-bit integer (number of pages)	1000	Takes effect on startup.	Determines upper bound for number of pages cache can allocate. On startup, actual upper bound is set to the larger of this parameter and cachePagesInit. Subsequently, changes to cachePagesInit are limited by upper bound calculated at startup.
cachePagesInit	32-bit integer (number of pages)	1000	Immediate.	Sets number of memory buffers to allocate from the OS for Fennel's data cache (also used as a pool for volatile scratch memory allocated by ExecStreams). Increasing it after startup causes new free buffers to be allocated; decreasing it causes buffers to be released (flushing them first if they contain dirty data). Note that this memory is NOT part of the JVM heap, although it shares the same virtual memory address space.
databaseInitSize	32-bit integer (number of pages)	1000	Only used at time of database creation; immutable after that.	Determines the number of pages desired when calculating the initial size of Fennel's db.dat file.
databaseIncrementSize	32-bit integer (number of pages, 0 to disable auto-increment)	1000	Takes effect on startup.	Determines number of pages by which to automatically extend the db.dat file when all existing pages have been allocated.
databaseMaxSize	32-bit integer (number of pages, 0 for unlimited)		Takes effect on startup.	Determines maximum size to which db.dat file can grow. Further allocations will fail even if space remains in the file system.
tempInitSize	32-bit integer (number of pages)	1000	Takes effect on startup.	Determines the number of pages desired when calculating the initial size of the temp.dat file. This file is recreated every time Fennel is loaded.
tempIncrementSize	32-bit integer (number of pages, 0 to disable auto-increment)	1000	Takes effect on startup.	Determines number of pages by which to automatically extend the temp.dat file when all existing pages have been allocated.
databaseShadowLogInitSize	32-bit integer (number of pages)	2000	Takes effect on startup.	Determines the number of pages desired when calculating the initial size of the shadowlog.dat file. This file is recreated every time Fennel is loaded, and is used as part of physical recovery.
databaseShadowLogIncrementSize	32-bit integer (number of pages, 0 to disable auto-increment)	1000	Takes effect on startup.	Determines number of pages by which to automatically extend the shadowlog.dat file when all existing pages have been allocated.
databaseTxnLogInitSize	32-bit integer (number of pages)	2000	Takes effect on startup.	Determines the number of pages desired when calculating the initial size of the txnlog.dat file. This file is recreated every time Fennel is loaded, and is used as part of logical recovery.
databaseTxnLogIncrementSize	32-bit integer (number of pages, 0 to disable auto-increment)	1000	Takes effect on startup.	Determines number of pages by which to automatically extend the txnlog.dat file when all existing pages have been allocated.
groupCommitInterval	32-bit integer (milliseconds)	30	Takes effect on startup.	Determines the amount of time to wait during commit in the hope that the commit's disk write can be combined with that of other concurrent transactions.
resourceDir	String (file-system path)	catalog/fennel under ${FARRAGO_HOME}	Takes effect on startup.	Sets the location of FennelResource.properties (or localized variant).
jniHandleTraceFile	String (file-system path)	{empty string}	Takes effect on startup.	See FennelJniHandleTracing.
expectedConcurrentStatements	32-bit integer (number of statements)	4	Immediate.	Indicates to the resource governor what is expected to be the maximum number of concurrent statements executing at any given time. It is used by the resource govenor to determine the maximum resource allocation for each statement.
cacheReservePercentage	32-bit integer (percentage between 1 and 99, inclusive)	5	Immediate.	The percentage of the Fennel data cache that should be set aside for global resource usage. The remainder will be available to allocate to individual statements.
connectionTimeoutMillis	long	86400000 (24hrs)	Takes effect on startup	Sets the timeout value for JDBC connections. -1 means never time out. Only affects VJDBC flavor of Farrago.
deviceSchedulerType	String (name of scheduler implementation)	null (let system decide)	Takes effect on startup	Controls the scheduler used for disk I/O. threadPool means to fake asynchronous I/O via a thread pool, and use buffered file access. On Linux, aioLinux means to use libaio for asynchronous I/O, with O_DIRECT for unbuffered file access. The default is to to use libaio if available, otherwise to fallback to threadPool. On Windows, ioCompletionPort (the default) means to use asynchronous I/O via completion ports and unbuffered file access. In all cases, if an unrecognized or unsupported value is set, the system silently reverts to default behavior to avoid causing startup failures.