Re: bytea vs. pg_dump
От | Bernd Helmle |
---|---|
Тема | Re: bytea vs. pg_dump |
Дата | |
Msg-id | 8FE72D48B69574341712FD55@teje обсуждение исходный текст |
Ответ на | Re: bytea vs. pg_dump (Peter Eisentraut <peter_e@gmx.net>) |
Ответы |
Re: bytea vs. pg_dump
Re: bytea vs. pg_dump Re: bytea vs. pg_dump Re: bytea vs. pg_dump Re: bytea vs. pg_dump |
Список | pgsql-hackers |
--On Samstag, Juli 11, 2009 13:40:44 +0300 Peter Eisentraut <peter_e@gmx.net> wrote: > OK, here is an updated patch. It has the setting as enum, completed > documentation, and libpq support. I'll add it to the commit fest in the > hope that someone else can look it over in detail. I've started looking at this and did some profiling with large bytea data again. For those interested, here are the numbers: Dumping with bytea_output=hex (COPY to file): real 20m38.699s user 0m11.265s sys 1m0.560s Dumping with bytea_output=escape (COPY to file): real 39m52.399s user 0m22.085s sys 1m50.131s So the time needed dropped about 50%. The dump file dropped from around 48 GB to 28 GB with the new format. I have some profiler data for this, but the restore seems much more interesting: the time to restore for both formats is quite the same: Restore bytea_output=hex real 32m11.028s user 0m0.000s sys 0m0.008s Restore bytea_output=escape real 31m35.378s user 0m0.000s sys 0m0.000s The profile for restoring the hex format looks like this: % cumulative self self total time seconds seconds calls s/call s/call name 34.54 156.79 156.79 97836 0.00 0.00 pglz_compress 18.64 241.38 84.59 141374 0.00 0.00 CopyReadLine 12.83 299.62 58.24 3604740854 0.00 0.00 get_hex 8.44 337.95 38.33 14257432 0.00 0.00 XLogInsert 7.39 371.48 33.53 141373 0.00 0.00 hex_decode 7.23 404.31 32.83 1 32.83 436.67 DoCopy 3.48 420.12 15.81 esc_enc_len 0.61 422.89 2.77 134943749 0.00 0.00 _bt_compare 0.54 425.36 2.47 33682172 0.00 0.00 ReadBuffer_common 0.54 427.83 2.47 52166324 0.00 0.00 hash_search_with_hash_value 0.45 429.89 2.06 104798203 0.00 0.00 LWLockAcquire 0.36 431.53 1.64 105234314 0.00 0.00 LWLockRelease I've attached a slightly edited patch which fixes a compiler warning in encode.c, too. -- Thanks Bernd
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