Compressed logs for keeper

[alesapin]

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Changelog category (leave one):

• Improvement

Changelog entry (a user-readable short description of the changes that goes to CHANGELOG.md):
Add compress_logs settings for clickhouse-keeper which allow to compress clickhouse-keeper logs in ZSTD . Implements: #26977.

[alesapin]

For some reason zstd still argues, while keeper is able to read compressed logs:

*** zstd command line interface 64-bits v1.3.3, by Yann Collet ***                                                                                                                                                                                                               
log_1_100000.bin.zst : 14 MB...     log_1_100000.bin.zst : Read error (39) : premature end                                                                                                                                                                                       ```
Maybe I have stale version.

[alesapin]

*** zstd command line interface 64-bits v1.4.9, by Yann Collet ***
0001_200000.bin.zstd : 43 MB...     0001_200000.bin.zstd : Read error (39) : premature end 

[alesapin]

@Mergifyio update

[mergify]

Command update: success

Branch has been successfully updated

[alesapin]

Ok, logs became much smaller. Now need to make snapshots compressed also with ZSTD (next PR).

[nikitamikhaylov]

Discussed a bit in private chat. Need to fix some issue.

[filimonov]

BTW - why not LZ4? It's few times faster (quite important for logs)

[alesapin]

BTW - why not LZ4? It's few times faster (quite important for logs)

Simpler stream compression, good compression ratio (about x10), small amount of data.

[alexey-milovidov]

LZ4 is too fast for ZooKeeper logs.
If we have around a gigabyte of ZooKeeper logs per second - it's way more significant problem.