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Add docs for WORKLOAD_NAME directive #1412

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Merged
frouioui merged 2 commits into from
Mar 16, 2023
Merged

Add docs for WORKLOAD_NAME directive #1412

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caf772d
Add docs for WORKLOAD_NAME directive
ejortegau Mar 10, 2023
f57af38
Fix typo
ejortegau Mar 10, 2023
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2 changes: 2 additions & 0 deletions content/en/docs/17.0/reference/programs/vttablet.md
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Expand Up @@ -147,6 +147,7 @@ The following global options apply to `vttablet`:
| --enable-consolidator-replicas | boolean | Synonym to -enable_consolidator_replicas |
| --enable-lag-throttler | boolean | Synonym to -enable_lag_throttler |
| --enable-tx-throttler | boolean | Synonym to -enable_tx_throttler |
| --enable-per-workload-table-metrics | boolean | Synonym to --enable_per_workload_table_metrics |
| --enable_consolidator | boolean | This option enables the query consolidator. (default true) |
| --enable_consolidator_replicas | boolean | This option enables the query consolidator only on replicas. |
| --enable_hot_row_protection | boolean | If true, incoming transactions for the same row (range) will be queued and cannot consume all txpool slots. |
Expand All @@ -156,6 +157,7 @@ The following global options apply to `vttablet`:
| --enable_transaction_limit | boolean | If true, limit on number of transactions open at the same time will be enforced for all users. User trying to open a new transaction after exhausting their limit will receive an error immediately, regardless of whether there are available slots or not. |
| --enable_transaction_limit_dry_run | boolean | If true, limit on number of transactions open at the same time will be tracked for all users, but not enforced. |
| --enable_tx_throttler | boolean | If true replication-lag-based throttling on transactions will be enabled. |
| --enable_per_workload_table_metrics | boolean | If true, query counts and query error metrics include a label that identifies the workload. |
| --enforce-tableacl- | config | if this flag is true, vttablet will fail to start if a valid tableacl config does not exist |
| --enforce_strict_trans_tables | boolean | If true, vttablet requires MySQL to run with STRICT_TRANS_TABLES or STRICT_ALL_TABLES on. It is recommended to not turn this flag off. Otherwise MySQL may alter your supplied values before saving them to the database. (default true) |
| --external-compressor | string | command with arguments to use when compressing a backup. |
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29 changes: 29 additions & 0 deletions content/en/docs/17.0/user-guides/configuration-advanced/comment-directives.md
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Expand Up @@ -90,3 +90,32 @@ select /*vt+ PLANNER=gen4 */ * from user;
```

Valid values are the same as for the planner flag - `v3` and `gen4`.

### Workload name (`WORKLOAD_NAME`)

Specifies the client application workload name. This does not affect query execution, but can be used to instrument
some `vttablet` metrics to include a label specifying the workload name. It can be useful if you are interested in
getting insights about how much of the work being done at the `vttablet` level is being caused by each client
application workload. For this to work, you must use `--enable-per-workload-table-metrics` at the `vttablet`, and pass
the client workload name on each query as a directive. For example:

```sql
select /*vt+ WORKLOAD_NAME=webstore */ * from commerce.customer;
```

will result in metrics such as this one:

```bash
% curl -s localhost:15100/metrics | grep "table=\"customer\"" |grep webstore
vttablet_query_counts{plan="Select",table="customer",workload="webstore"} 1
vttablet_query_error_counts{plan="Select",table="customer",workload="webstore"} 0
vttablet_query_rows_returned{plan="Select",table="customer",workload="webstore"} 0
vttablet_query_times_ns{plan="Select",table="customer",workload="webstore"} 602557
```

As shown above, the metrics being instrumented this way are `vttablet_query_counts`, `vttablet_query_error_counts`,
`vttablet_query_rows_returned` and `vttablet_query_times_ns`.

If the query lacks the `WORKLOAD_NAME` directive, the corresponding label in the metric will have the value of an empty
string. If `vttablet` is not started with `--enable-per-workload-table-metrics`, metrics are emitted without the
workload label (e.g. `vttablet_query_counts{plan="Select",table="customer"}`.