| --- |
| title: hawq start |
| --- |
| |
| Starts a HAWQ system. |
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| ## Synopsis<a id="topic1__section2"></a> |
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| ``` pre |
| hawq start object [-l| --logdir] [-q| --quiet] |
| [-v|--verbose] [-m|--masteronly] [-t|--timeout timeout_seconds] |
| [-R | --restrict] [-U | --special-mode maintenance] |
| [--ignore_bad-hosts] cluster | allsegments |
| |
| ``` |
| |
| ``` pre |
| hawq start -? | -h | --help |
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| hawq start --version |
| ``` |
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| ## Description<a id="topic1__section3"></a> |
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| The `hawq start` utility is used to start the HAWQ server processes. When you start a HAWQ system, you are actually starting several `postgres` database server listener processes at once (the master and all of the segment instances). The `hawq start` utility handles the startup of the individual instances. Each instance is started in parallel. |
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| The *object* in the command specifies what entity should be started: e.g. a cluster, a segment, the master node, standby node, or all segments in the cluster. |
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| The first time an administrator runs `hawq start cluster`, the utility creates a static hosts cache file named `$GPHOME/etc/slaves` to store the segment host names. Subsequently, the utility uses this list of hosts to start the system more efficiently. The utility will create a new hosts cache file at each startup. |
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| The `hawq start master` command starts only the HAWQ master, without segment or standby nodes. These can be started later, using `hawq start segment` and/or `hawq start standby`. |
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| **Note:** Typically you should always use `hawq start cluster` or `hawq restart cluster` to start the cluster. If you do end up using `hawq start standby|master|segment` to start nodes individually, make sure you always start the standby before the active master. Otherwise, the standby can become unsynchronized with the active master. |
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| Before you can start a HAWQ system, you must have initialized the system or node by using `hawq init <object>` first. |
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| ## Objects |
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| cluster |
| Start a HAWQ cluster. |
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| master |
| Start HAWQ master. |
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| segment |
| Start a local segment node. |
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| standby |
| Start a HAWQ standby. |
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| allsegments |
| Start all segments. |
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| ## Options<a id="topic1__section4"></a> |
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| -l --logdir *logfile\_directory* |
| Specifies the log directory for logs of the management tools. The default is `~/hawq/Adminlogs/`. |
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| -q --quiet |
| Run in quiet mode. Command output is not displayed on the screen, but is still written to the log file. |
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| -v --verbose |
| Displays detailed status, progress and error messages output by the utility. |
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| -m --masteronly |
| Optional. Starts the HAWQ master instance only, in utility mode, which may be useful for maintenance tasks. This mode only allows connections to the master in utility mode. For example: |
| |
| ``` pre |
| PGOPTIONS='-c gp_role=utility' psql |
| ``` |
| |
| -R --restrict (restricted mode) |
| Starts HAWQ in restricted mode (only database superusers are allowed to connect). |
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| -t --timeout *timeout\_seconds* |
| Specifies a timeout in seconds to wait for a segment instance to start up. If a segment instance was shutdown abnormally (due to power failure or killing its `postgres` database listener process, for example), it may take longer to start up due to the database recovery and validation process. If not specified, the default timeout is 60 seconds. |
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| -U --special-mode maintenance |
| (Superuser only) Start HAWQ in \[maintenance | upgrade\] mode. In maintenance mode, the `gp_maintenance_conn` parameter is set. |
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| --ignore\_bad\_hosts cluster | allsegments |
| Overrides copying configuration files to a host on which SSH validation fails. If ssh to a skipped host is reestablished, make sure the configuration files are re-synched once it is reachable. |
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| -? | -h | --help (help) |
| Displays the online help. |
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| --version (show utility version) |
| Displays the version of this utility. |
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| ## Examples<a id="topic1__section5"></a> |
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| Start a HAWQ system: |
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| ``` pre |
| hawq start cluster |
| ``` |
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| Start a HAWQ master in maintenance mode: |
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| ``` pre |
| hawq start master -m |
| ``` |
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| Start a HAWQ system in restricted mode (only allow superuser connections): |
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| ``` pre |
| hawq start cluster -R |
| ``` |
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| Start the HAWQ master instance only and connect in utility mode: |
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| ``` pre |
| hawq start master -m PGOPTIONS='-c gp_session_role=utility' psql |
| ``` |
| |
| ## See Also<a id="topic1__section6"></a> |
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| /3/4, /3/4 |
