| From: | Heikki Linnakangas <hlinnakangas(at)vmware(dot)com> |
|---|---|
| To: | Amit Kapila <amit(dot)kapila(at)huawei(dot)com> |
| Cc: | 'Alvaro Herrera' <alvherre(at)2ndquadrant(dot)com>, 'PostgreSQL-development' <pgsql-hackers(at)postgreSQL(dot)org> |
| Subject: | Re: Optimizing pglz compressor |
| Date: | 2013-06-25 20:45:09 |
| Message-ID: | 51CA0155.9030903@vmware.com |
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| Thread: | |
| Lists: | pgsql-hackers |
On 19.06.2013 14:01, Amit Kapila wrote:
> Observations
> --------------
> 1. For small data perforamce is always good with patch.
> 2. For random small/large data performace is good.
> 3. For medium and large text and same byte data(3K,5K text, 10K,100K,500K
> same byte), performance is degraded.
Wow, that's strange. What platform and CPU did you test on? Are you sure
you used the same compiler flags with and without the patch?
Can you also try the attached patch, please? It's the same as before,
but in this version, I didn't replace the prev and next pointers in
PGLZ_HistEntry struct with int16s. That avoids some table lookups, at
the expense of using more memory. It's closer to what we have without
the patch, so maybe that helps on your system.
- Heikki
| Attachment | Content-Type | Size |
|---|---|---|
| pglz-variable-size-hash-table-2.patch | text/x-diff | 7.7 KB |
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