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Merge pull request fluent#395 from daipom/fix-wrong-calculation-of-retry
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1.0: Fix wrong description of total retry time
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ashie authored Mar 31, 2022
2 parents 230158a + 06de24a commit 7df3e8b
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2 changes: 1 addition & 1 deletion buffer/README.md
Original file line number Diff line number Diff line change
Expand Up @@ -41,7 +41,7 @@ A chunk can fail to be written out to the destination for a number of reasons. T
By default, Fluentd increases the wait interval exponentially for each retry attempt. For example, assuming that the initial wait interval is set to 1 second and the exponential factor is 2, each attempt occurs at the following time points:

```text
1 2 4 8 16
0 1 3 7 15
x-x---x-------x---------------x-------------------------
│ │ │ │ └─ 4th retry (wait = 8s)
│ │ │ └───────────────── 3th retry (wait = 4s)
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9 changes: 7 additions & 2 deletions configuration/buffer-section.md
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Expand Up @@ -494,7 +494,11 @@ Following are the flushing parameters for chunks to optimize performance \(laten
* Default: 72h
* The maximum time \(seconds\) to retry to flush again the failed chunks,

until the plugin discards the buffer chunks
until the plugin discards the buffer chunks.

If the next retry is going to exceed this time limit, the last retry

will be made at exactly this time limit.
* `retry_forever` \[bool\]
* Default: `false`
* If true, plugin will ignore `retry_timeout` and `retry_max_times`
Expand Down Expand Up @@ -546,7 +550,8 @@ With `exponential_backoff`, `retry_wait` interval will be calculated as below:
* c: constant factor, `@retry_wait`
* b: base factor, `@retry_exponential_backoff_base`
* k: number of retry times
* total retry time: `c + c * b^1 + (...) + c*b^k = c*b^(k+1) - 1`
* total retry time: `c + c*b^1 + (...) + c*b^(k-1) = c*(b^k - 1) / (b - 1)`
* = `2^k - 1` by default

If this article is incorrect or outdated, or omits critical information, please [let us know](https://github.com/fluent/fluentd-docs-gitbook/issues?state=open). [Fluentd](http://www.fluentd.org/) is an open-source project under [Cloud Native Computing Foundation \(CNCF\)](https://cncf.io/). All components are available under the Apache 2 License.

50 changes: 47 additions & 3 deletions output/README.md
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Expand Up @@ -181,6 +181,18 @@ If the bottom chunk write out fails, it will remain in the queue and Fluentd wil

Writing out the bottom chunk is considered to be a failure if `Output#write` or `Output#try_write` method throws an exception.

The retry timings of `retry_timeout: 100s`.

| N-th retry | Elapsed |
| :--- | :--- |
| 1th | 1s |
| 2th | 3s |
| 3th | 7s |
| 4th | 15s |
| 5th | 31s |
| 6th | 63s |
| 7th | 100s |

#### `retry_type`

Specifies how to wait for the next retry to flush buffer.
Expand All @@ -198,13 +210,13 @@ Default: `false`

#### `retry_timeout`

The maximum seconds to retry to flush while failing, until the plugin discards the buffer chunks.
The maximum seconds to retry to flush while failing, until the plugin discards the buffer chunks. If the next retry is going to exceed this time limit, the last retry will be made at exactly this time limit.

Default: `72` \(hours\)
Default: `72h` \(72 hours\)

#### `retry_max_times`

The maximum number of times to retry to flush while failing. If `retry_timeout` is the default, the number is 17 with exponential backoff.
The maximum number of times to retry to flush while failing. If `retry_timeout` is the default, the number is 18 with exponential backoff.

Default: `nil`

Expand Down Expand Up @@ -268,5 +280,37 @@ This example sends logs to Elasticsearch using a file buffer `/var/log/td-agent/

NOTE: `<secondary>` plugin receives the primary's buffer chunk directly. So, you need to check if your secondary plugin works with the primary setting.

The retry timings of `retry_timeout: 100s` with the secondary.

| N-th retry | Elapsed | Output plugin |
| :--- | :--- | :--- |
| 1th | 1s | primary |
| 2th | 3s | primary |
| 3th | 7s | primary |
| 4th | 15s | primary |
| 5th | 31s | primary |
| 6th | 63s | primary |
| 7th | 80s | secondary |
| 8th | 81s | secondary |
| 9th | 83s | secondary |
| 10th | 87s | secondary |
| 11th | 95s | secondary |
| 12th | 100s | secondary |

The retry timings of `retry_max_times: 10` with the secondary.

| N-th retry | Elapsed | Output plugin |
| :--- | :--- | :--- |
| 1th | 1s | primary |
| 2th | 3s | primary |
| 3th | 7s | primary |
| 4th | 15s | primary |
| 5th | 31s | primary |
| 6th | 63s | primary |
| 7th | 127s | primary |
| 8th | 255s | primary |
| 9th | 511s | primary |
| 10th | 818s | secondary |

If this article is incorrect or outdated, or omits critical information, please [let us know](https://github.com/fluent/fluentd-docs-gitbook/issues?state=open). [Fluentd](http://www.fluentd.org/) is an open-source project under [Cloud Native Computing Foundation \(CNCF\)](https://cncf.io/). All components are available under the Apache 2 License.

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