Database Options
Database options and database process options control the activity of database processes. Options specified on the database will be applied to all processes started for that database while database process options apply to Transaction Engine (TE) and Storage Manager (SM) database processes only. All options take effect at process start time for a TE or SM.
The following table provides information for database options. For each option, the table below lists the following:
- Option Name
-
These are case sensitive.
- Option Argument
-
Either a list of possible values in curly brackets or an indication of the type of argument expected (such as
file
,directory
ormilliseconds
). - Default Argument
-
Where a default exists, may be empty.
- Description
-
Details the behavior controlled by the option.
- Restrictions
-
Some options can only be applied at the database level when the database is created. These will be used when any processes are started for the database. Some options apply to only certain database processes, for example, the
journal-max-directory-entries
option applies to SMs but not TEs. These are called database process options. Some options can be specified at the database level or specified as a database process option when the process is started.This distinction is listed in the restrictions column in the table below as one of the following:
-
Database for a database option
-
TE for a database process option that applies to TEs
-
SM for a database process option that applies to SMs
If no restrictions are specified for an option, then it can be used as both database option and database process option.
-
Available Options
Option Name | Option Argument | Default Argument | Description | Restrictions | ||
---|---|---|---|---|---|---|
|
|
1 |
Number of parallel archive write threads. Increasing the value is recommended when using high latency storage, which is typical with Cloud storage or a Storage Area Network (SAN). |
SM |
||
|
|
600 (10 minutes) |
Amount of time that an Asynchronous SM may delay record version garbage collection to prevent discarding the last consistent state. If this time is exceeded, the Asynchronous SM will log a message and shutdown. |
ASM |
||
|
|
|
Specifies accepted encryption protocols available for all connections to Transaction Engines (TEs), Administration Processes (APs), and SQL clients. Protocol preference, is defined by the order in which they are listed as comma-separated values. For more information on encryption protocols, see Network Encryption. |
|||
|
|
None |
Specifies a configuration file to be passed to the TE, SM process. The configuration file can contain any of the options in this table, represented as key/value pairs, where each key is separated from its value with whitespace, and each key/value pair resides on its own line in the file. This configuration file will be passed to all processes (TEs, SMs) in the database. If the configuration file contains any options that might refer to a local directory path, this path must exist on all database hosts. |
|||
|
|
|
Specifies a directory in which to place crash reports for NuoDB processes (TEs, SMs).
This option is for Linux only. |
|||
{ |
|
Disables For more information, see ANALYZE. |
TE |
|||
|
|
|
Allows the use of Embedded Java. For more information, see Using the Embedded Java API.
|
TE |
||
|
|
|
Allows TEs to terminate user queries in order to relieve memory pressure. For more information, see SQL Query Termination. |
|||
|
Comma-separated list of cipher names |
|
A list of acceptable ciphers for clients to connect to the database with.
The first cipher is the most preferred. Cipher names are case-sensitive and must be entered exactly as shown. The client will supply a list if ciphers it accepts: if no overlap is found the connection will be refused. The full list of available ciphers are: |
|||
|
|
|
Number of threads used when copying atoms during a hot copy operation. For more information on performing hot copy operations, see Backing Up and Restoring Databases. |
SM |
||
|
|
|
A message is logged when a disk I/O operation takes longer than the value specified for this option. These log message are prepended with "Slow I/O:…". |
|||
|
|
|
A message is logged, and the process is killed, when a disk I/O operation takes longer than the value specified for this option. This avoids a scenario where the entire database hangs because one disk is not responding. |
|||
|
|
|
The maximum number of bytes considered to be a single I/O operation by the underlying storage facility. |
|||
|
|
|
Enable journal hot copy on the current SM. |
SM |
||
|
|
|
Sets the maximum number of journal files in a journal sub-directory. A new journal sub-directory is created when the specified limit has been reached. |
SM |
||
|
|
|
Specifies the maximum size in bytes of a journal file. However, the journal may write a file larger than the maximum file size if a single compressed journal message is larger than the specified maximum. The journal messages will be appended to the same journal file until the maximum file size is reached. |
SM |
||
|
|
|
Specifies the file system synchronization mechanism when the journal needs to ensure the durability of a commit. The synchronization mechanism has been specifically tuned for each supported OS.
|
SM |
||
|
|
If a value is set for On Linux: standard paths are searched. On Windows: the Windows registry is checked and then common paths are checked. |
TE |
|||
|
|
Required for LDAP authentication. Starting point for the LDAP search instead of the default Example:
|
TE |
|||
|
|
Optional. LDAP certificate authority certificate to validate server certificate for |
TE |
|||
|
|
Optional. LDAP path to ldap.conf file too use (see |
TE |
|||
|
|
Required for LDAP authentication. This, in conjunction with ldap-pass, allows proxy level authentication and the specified account must have search privileges on the ldap-base. It is used to search for the full Distinguished Name (DN) of the user that connects. Example:
|
TE |
|||
|
|
Optional. LDAP openldap library name (Linux only) |
TE |
|||
|
|
Required for LDAP authentication.
This, in conjunction with |
TE |
|||
|
|
Required for LDAP authentication. LDAP server type. Only |
TE |
|||
|
|
Required for LDAP authentication. Specify URI referring to Example:
the LDAP server(s). |
TE |
|||
|
|
1 |
The number of threads the loader will use to load atoms from disk. |
|||
|
n |
10 |
Maximum allowed wasted space in one LSA-file before it becomes a candidate for compaction, as a percentage. |
SM |
||
|
n |
2097152 (2 MB) |
Target size of an LSA-file, in bytes. |
SM |
||
|
n |
75 |
Maximum allowed wasted space in a catalog’s LSA-map-files before they become candidates for compaction, as a percentage. |
SM |
||
|
n |
30 |
Percentage of wasted disk space in Log-Structured Archive (LSA) to trigger the compaction process. |
SM |
||
|
n |
20 |
Percentage of wasted disk space in LSA to stop the compaction process. |
SM |
||
|
|
|
The number of concurrent client connections a TE will accept. When starting a TE, use this property to set a specific number of client connections. For more information, see Setting Client Connection Limits for Transaction Engines. The default (0) allows the TE to accept as many connections as are allowed by the operating system (that is, the same number of sockets that the process can open), minus some reserved for database operations. If the TE cannot accept the number of connections requested (because the operating system does not allow that many open sockets), the TE does not start.
Setting a non-zero value for this startup parameter results in the TE refusing new client connections if the number of current open connections is equal to the value. |
TE |
||
|
|
Specifies the number of normal garbage collection cycles to every full garbage collection cycle (which is every 1000 seconds). By default, there are 100 normal garbage collection cycles to every full garbage collection cycle. For information on generating index statistics, see ANALYZE. |
||||
|
|
|
The number of leader candidates that may be permanently lost (crash and become non-restartable) at a time before durability is compromised. For a database to be available to commit update transactions, max-lost-archives + 1 leader candidates must be running in the system. The default is 0, meaning that the system is resilient to any number of ordinary failures and available for updates as long as at least one leader candidate is running; but, if 1 or more leader candidates is permanently lost then durability may be compromised. When max-lost-archives > 0, the transaction can fail to commit, and then roll back. But if the whole database fails before the transaction completes roll back, the partially rolled back transaction can be dredged as pre-committed and promoted to committed, thus creating a torn transaction. |
|||
|
|
16 Mi |
Maximum amount of memory (in bytes), that can be used before spill-to-disk, during Stats v3 histogram generation. |
SM |
||
|
|
|
The maximum number of unique normalized statement entries stored in the |
TE |
||
|
|
Sets the maximum amount of memory to be utilized by a database process (in bytes). To specify the amount in kilo-, mega-, giga-, kibi-, mebi-, or gibibytes, suffix the amount with K, M, G, Ki, Mi, or Gi (respectively). |
||||
|
|
Maximum messages received per second (for testing only) |
||||
|
|
NuoDB decides |
Port to use for this host, or optionally, a range of port values. By default NuoDB determines the port to be used. |
|||
|
|
4 |
Maximum number of threads to consider for execution on each node, the optimizer may choose to use less threads than this. If set to 1, parallel query execution will be disabled. |
TE |
||
|
|
100000 |
Determines the minimum number of rows estimated to be scanned, in both partitioned and non-partitioned tables, before considering parallel execution. |
TE |
||
|
Comma-separated list of cipher names |
|
A list of acceptable ciphers for peers to connect to the database with.
This includes other SMs or TEs as well as connections to the admin services.
The first cipher is the most preferred. Cipher names are case-sensitive and must be entered exactly as shown.
The client will supply a list if ciphers it accepts: if no overlap is found the connection is refused. The full list of available ciphers are: |
|||
|
Not set |
Normally, processes in the database (TEs, SMs) ping other processes at regular intervals and wait for a response. When network communication with a process times out, the process is evicted from the database by its peers. |
Database |
|||
|
None |
Equivalent to the |
||||
|
Not set |
Send all logging information to the server at the specified remote host and port number. If not specified, the port number defaults to 514. |
||||
|
|
N/A |
Specifies a directory that NuoDB can use for temporary files to facilitate the processing of memory intensive operations. For SMs, the default value for |
Database |
||
|
|
|
Sets the maximum size of the
|
|||
|
|
If any table reaches this cardinality (number of rows), index statistics will cease to be collected automatically for it.
Statistics may still be collected manually by issuing the |
||||
|
|
Enable or disable automatic v2 statistics updates. |
||||
|
|
The query optimizer statistics version. |
||||
|
|
Not set |
Enable and configure TCP keepalive on incoming SQL client connections.
Format |
|||
|
|
|
The number of longest-running statements for which performance metrics are logged during each logging cycle. |
TE |
||
|
duration (d, h, m, s) |
|
The frequency at which performance metrics for the longest-running statements are logged.
|
TE |
||
|
storage group names |
None |
A comma-separated list of storage group names that the Asynchronous SM observes, but does not lead.
This is controlled by the |
ASM |
||
|
|
Send logging information to the system log (only if TE or SM is running on a Unix host). |
||||
|
|
None |
Report logging and other information. This information is captured in the |
Logging Options
To use the remote-syslog
, syslog
or verbose
options, you must specify at least one logging level and/or logging category to log.
For details refer to Logging Options.