[
https://issues.apache.org/jira/browse/COUCHDB-1120?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13027175#comment-13027175
]
Filipe Manana commented on COUCHDB-1120:
----------------------------------------
I've created another branch on top of the previous one which makes compression
optional and also adds the possibility to use deflate (zlib) compression:
https://github.com/fdmanana/couchdb/compare/file_compression
By default, snappy compression is enabled. The compression is configured in the
section [couchdb]:
https://github.com/fdmanana/couchdb/compare/file_compression#diff-4
For those interested, after checking out snappy from google code (
http://code.google.com/p/snappy/ ), one can run some benchmark tests to compare
snappy against zlib, lzo and other algorithms. This is done by running:
$ ./snappy_unittest -run_microbenchmarks=false --zlib --lzo testdata/*
Output example at http://friendpaste.com/7YVC8jImnY2GbnOLJvce6x
The tests I presented before, as well as the following ones, show that snappy
has a positive impact on the database read/write performance and view indexer
performance.
Here are a few more tests against 2 different databases/views.
***** Database with 551 200 documents, each with a size of about 1 Kb *****
Database created with:
$ ./seatoncouch.rb --host localhost --port 5984 --docs 551200 --threads 20
--db-name complex_keys \
--bulk-batch 100 --doc-tpl complex_keys.tpl
The document template can be found here:
http://friendpaste.com/1cRdpfPyzWzoQKo8zb3fky
The database has following design document:
{
"_id": "_design/test",
"language": "javascript",
"views": {
"view1": {
"map": "function(doc) { emit([doc.type, doc.category, doc.level,
doc.ratio], doc.nested.coords); }"
},
"view2": {
"map": "function(doc) { emit(doc._id, {type: doc.type, cat:
doc.category, level: doc.level, ratio: doc.ratio}); }"
}
}
}
* trunk *
database file size after compaction: 1592 Mb
view file size after compaction: 520 Mb
view index build time:
$ time curl
http://localhost:5984/trunk_complex_keys/_design/test/_view/view1?limit=1
{"total_rows":551200,"offset":0,"rows":[
{"id":"00d49881-7bcf-4c3d-a65d-e44435eeb513","key":["dwarf","assassin",2,1.1],"value":[{"x":174347.18,"y":127272.8},{"x":35179.93,"y":41550.55},{"x":157014.38,"y":172052.63},{"x":116185.83,"y":69871.73},{"x":153746.28,"y":190006.59}]}
]}
real 25m47.395s
user 0m0.008s
sys 0m0.040s
*** branch file_compression with snappy compression enabled ***
database file size after compaction: 1215 Mb
view file size after compaction: 155 Mb
view index build time:
$ time curl
http://localhost:5985/snappy_complex_keys/_design/test/_view/view1?limit=1
{"total_rows":551200,"offset":0,"rows":[
{"id":"00d49881-7bcf-4c3d-a65d-e44435eeb513","key":["dwarf","assassin",2,1.1],"value":[{"x":174347.18,"y":127272.8},{"x":35179.93,"y":41550.55},{"x":157014.38,"y":172052.63},{"x":116185.83,"y":69871.73},{"x":153746.28,"y":190006.59}]}
]}
real 12m11.829s
user 0m0.004s
sys 0m0.020s
*** branch file_compression with deflate compression level 1 enabled ***
database file size after compaction: 1097 Mb
view file size after compaction: 123 Mb
view index build time:
$ time curl
http://localhost:5985/deflate1_complex_keys/_design/test/_view/view1?limit=1
{"total_rows":551200,"offset":0,"rows":[
{"id":"00d49881-7bcf-4c3d-a65d-e44435eeb513","key":["dwarf","assassin",2,1.1],"value":[{"x":174347.18,"y":127272.8},{"x":35179.93,"y":41550.55},{"x":157014.38,"y":172052.63},{"x":116185.83,"y":69871.73},{"x":153746.28,"y":190006.59}]}
]}
real 19m32.945s
user 0m0.000s
sys 0m0.036s
*** branch file_compression with deflate compression level 9 enabled ***
database file size after compaction: 1092 Mb
view file size after compaction: 118 Mb
view index build time:
$ time curl
http://localhost:5985/deflate9_complex_keys/_design/test/_view/view1?limit=1
{"total_rows":551200,"offset":0,"rows":[
{"id":"00d49881-7bcf-4c3d-a65d-e44435eeb513","key":["dwarf","assassin",2,1.1],"value":[{"x":174347.18,"y":127272.8},{"x":35179.93,"y":41550.55},{"x":157014.38,"y":172052.63},{"x":116185.83,"y":69871.73},{"x":153746.28,"y":190006.59}]}
]}
real 21m50.390s
user 0m0.012s
sys 0m0.036s
***** Benoit's warlogs database (https://warlogs.upondata.com/warlogs), 391 835
documents *****
*** trunk ***
database file size after compaction: 1090 Mb
view file size after compaction: 1.3 Gb
view index build time:
$ time curl
http://localhost:5984/warlogs_trunk/_design/warlogs/_view/by_date?limit=1
{"total_rows":391832,"offset":0,"rows":[
{"id":"0104D7FC-0219-4C16-8531-97C60A59C70C","key":["2004-01","0104D7FC-0219-4C16-8531-97C60A59C70C"],"value":null}
]}
real 44m10.341s
user 0m0.021s
sys 0m0.050s
*** branch file_compression with snappy compression enabled ***
database file size after compaction: 843 Mb
view file size after compaction: 616 Mb
view index build time:
$ time curl
http://localhost:5985/warlogs_snappy/_design/warlogs/_view/by_date?limit=1
{"total_rows":391832,"offset":0,"rows":[
{"id":"0104D7FC-0219-4C16-8531-97C60A59C70C","key":["2004-01","0104D7FC-0219-4C16-8531-97C60A59C70C"],"value":null}
]}
real 32m53.988s
user 0m0.036s
sys 0m0.024s
*** branch file_compression with deflate compression level 1 enabled ***
database file size after compaction: 803 Mb
view file size after compaction: 459 Mb
view index build time:
time curl
http://localhost:5985/warlogs_deflate1/_design/warlogs/_view/by_date?limit=1
{"total_rows":391832,"offset":0,"rows":[
{"id":"0104D7FC-0219-4C16-8531-97C60A59C70C","key":["2004-01","0104D7FC-0219-4C16-8531-97C60A59C70C"],"value":null}
]}
real 43m1.360s
user 0m0.008s
sys 0m0.068s
*** branch file_compression with deflate compression level 9 enabled ***
database file size after compaction: 798 Mb
view file size after compaction: 435 Mb
view index build time:
$ time curl
http://localhost:5985/warlogs_deflate9/_design/warlogs/_view/by_date?limit=1
{"total_rows":391832,"offset":0,"rows":[
{"id":"0104D7FC-0219-4C16-8531-97C60A59C70C","key":["2004-01","0104D7FC-0219-4C16-8531-97C60A59C70C"],"value":null}
]}
real 47m10.841s
user 0m0.032s
sys 0m0.060s
I made several relaximation read and writes tests, as well as writes only tests
(as shown in the very first comment) and found out that both the reads and
writes get a positive impact:
1) relaximation reads and writes test, 1 Kb documents (snappy compression vs
trunk):
http://graphs.mikeal.couchone.com/#/graph/698bf36b6c64dbd19aa2bef6340655b7
(The 1 Kb document can be found here:
http://friendpaste.com/28yMMCXn5Dd0EPFpryrvMt
2) relaximation reads and writes test, 2.5 Kb documents (snappy compression vs
trunk):
http://graphs.mikeal.couchone.com/#/graph/698bf36b6c64dbd19aa2bef634064d2d
(The 2.5 Kb document can be found here:
http://friendpaste.com/24dnXQT8FZ2gqGLI8571oV)
3) relaximation reads and writes test, 8 Kb documents (snappy compression vs
trunk):
http://graphs.mikeal.couchone.com/#/graph/698bf36b6c64dbd19aa2bef634064f56
(The 8 Kb document can be found here:
http://friendpaste.com/2QN9TrpJA8476VzLzX0imy)
4) relaximation reads and writes test, 8 Kb documents (deflate level 1
compression vs trunk):
http://graphs.mikeal.couchone.com/#/graph/698bf36b6c64dbd19aa2bef634065e8f
With deflate level 1 compression, reads seem to stay about the same, while
writes are still slightly better compared to trunk.
I've also observed that in my machine, decompressing 100Kb with snappy is very
fast, taking between 100us and 150us, while zlib takes about ten times more for
the same amount of data (which confirms the snappy benchmarks tests).
> Snappy compression (databases, view indexes) + keeping doc bodies as ejson
> binaries
> ------------------------------------------------------------------------------------
>
> Key: COUCHDB-1120
> URL: https://issues.apache.org/jira/browse/COUCHDB-1120
> Project: CouchDB
> Issue Type: Improvement
> Components: Database Core
> Environment: trunk
> Reporter: Filipe Manana
> Assignee: Filipe Manana
>
> The branch at:
> https://github.com/fdmanana/couchdb/compare/snappy
> Is an experiment which adds snappy compression to database files and view
> index files. Snappy is a very fast compressor/decompressor developed by and
> used by Google [1] - even for small data chunks like 100Kb it can be 2 orders
> of magnitude faster then zlib or Erlang's term_to_binary compression level 1.
> Somewhere at [1] there are benchmark results published by Google that compare
> against zlib's deflate, Erlang's term_to_binary compression, lzo, etc.
> Even small objects like database headers or btree nodes, still get smaller
> after compressing them with snappy, see the shell session at [2].
> Besides the compression, this branch also keeps the document bodies
> (#doc.body fields) as binaries (snappy compressed ejson binaries) and only
> converts them back to ejson when absolutely needed (done by
> couch_doc:to_json_obj/2 for e.g.) - this is similar to COUCHDB-1092 - but the
> bodies are EJSON compressed binaries and doesn't suffer from the same issue
> Paul identified before (which could be fixed without many changes) - on reads
> we decompress and still do the binary_to_term/1 + ?JSON_ENCODE calls as
> before.
> It also prepares the document summaries before sending the documents to the
> updater, so that we avoid copying EJSON terms and move this task outside of
> the updater to add more parallelism to concurrent updates.
> I made some tests, comparing trunk before and after the JSON parser NIF was
> added, against this snappy branch.
> I created databases with 1 000 000 documents of 4Kb each. The document
> template is this one: http://friendpaste.com/qdfyId8w1C5vkxROc5Thf
> The databases have this design document:
> {
> "_id": "_design/test",
> "language": "javascript",
> "views": {
> "simple": {
> "map": "function(doc) { emit(doc.data5.float1, [doc.strings[2],
> doc.strings[10]]); }"
> }
> }
> }
> == Results with trunk ==
> database file size after compaction: 7.5 Gb
> view index file size after compaction: 257 Mb
> ** Before JSON nif:
> $ time curl
> 'http://localhost:5985/trunk_db_1m/_design/test/_view/simple?limit=1'
> {"total_rows":1000000,"offset":0,"rows":[
> {"id":"00000632-d25d-49c6-9b4e-e038b78ff97d","key":76.572,"value":["jURcBZ0vrJcmf2roZUMzZJQoTsKZDIdj7KhO7itskKvM80jBU9","fKYYthv8iFvaYoFoYZyB"]}
> ]}
> real 58m28.599s
> user 0m0.036s
> sys 0m0.056s
> ** After JSON nif:
> fdmanana 12:45:55 /opt/couchdb > time curl
> 'http://localhost:5985/trunk_db_1m/_design/test/_view/simple?limit=1'
> {"total_rows":1000000,"offset":0,"rows":[
> {"id":"00000632-d25d-49c6-9b4e-e038b78ff97d","key":76.572,"value":["jURcBZ0vrJcmf2roZUMzZJQoTsKZDIdj7KhO7itskKvM80jBU9","fKYYthv8iFvaYoFoYZyB"]}
> ]}
> real 51m14.738s
> user 0m0.040s
> sys 0m0.044s
> == Results with the snappy branch ==
> database file size after compaction: 3.2 Gb (vs 7.5 Gb on trunk)
> view index file size after compaction: 100 Mb (vs 257 Mb on trunk)
> ** Before JSON nif:
> $ time curl
> 'http://localhost:5984/snappy_db_1m/_design/test/_view/simple?limit=1'
> {"total_rows":1000000,"offset":0,"rows":[
> {"id":"00000632-d25d-49c6-9b4e-e038b78ff97d","key":76.572,"value":["jURcBZ0vrJcmf2roZUMzZJQoTsKZDIdj7KhO7itskKvM80jBU9","fKYYthv8iFvaYoFoYZyB"]}
> ]}
> real 32m29.854s
> user 0m0.008s
> sys 0m0.052s
> ** After JSON nif:
> fdmanana 15:40:39 /opt/couchdb > time curl
> 'http://localhost:5984/snappy_db_1m/_design/test/_view/simple?limit=1'
> {"total_rows":1000000,"offset":0,"rows":[
> {"id":"00000632-d25d-49c6-9b4e-e038b78ff97d","key":76.572,"value":["jURcBZ0vrJcmf2roZUMzZJQoTsKZDIdj7KhO7itskKvM80jBU9","fKYYthv8iFvaYoFoYZyB"]}
> ]}
> real 18m39.240s
> user 0m0.012s
> sys 0m0.020s
> A writes-only relaximation test also shows a significant improvement in the
> writes response times / throughput:
> http://graphs.mikeal.couchone.com/#/graph/698bf36b6c64dbd19aa2bef63405480d
> These results are also in a file of this branch [3].
> Seems clear this, together with Paul's JSON NIF parser, has a very good
> impact in the view indexer, besides the big disk space savings and better
> write throughput.
> Some potential issues:
> * Snappy is C++, and so is the NIF [4] - however a C++ compiler is common and
> part of most development environments (gcc, xcode, etc)
> * Not sure if snappy builds on Windows - it might build, it doesn't seem to
> depend on fancy libraries, just stdc++ and the STL
> * Requires OTP R13B04 or higher. If built/running on R13B03 or below, it
> simple doesn't do any compression at all, just like current releases.
> However, 2 servers running this branch, one with R14 and other R13B01 for
> e.g., means that the second server will not be able to read database files
> created by the server with R14 - it will get an exception with the atom
> 'snappy_nif_not_loaded' - this is easy to catch and use for printing a nice
> and explicit error message to the user telling it needs to use a more recent
> otp release.
> The upgrade of databases and view indexes from previous releases is done on
> compaction - I made just a few tests with database files by hand, this surely
> needs to be better tested.
> Finally the branch is still in development phase, but maybe not far from
> completion, consider this ticket just as a way to share some results and get
> some feedback.
> [1] - http://code.google.com/p/snappy/
> [2] - http://friendpaste.com/45AOdi9MkFrS4BPsov7Lg8
> [3] -
> https://github.com/fdmanana/couchdb/blob/b8f806e41727ba18ed6143cee31a3242e024ab2c/snappy-couch-tests.txt
> [4] - https://github.com/fdmanana/snappy-erlang-nif/
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