Marinos,
what if you construct "apachebench & Co" free script and see if
the issue still exists. There are could be many issues doesn't
connected to postgresql and tsearch2.
Oleg
On Thu, 3 Feb 2005, Marinos J. Yannikos wrote:
Oleg Bartunov wrote:
On Thu, 3 Feb 2005, Marinos J. Yannikos wrote:
concurrent access to GiST indexes isn't possible at the moment. I [...]
there are should no problem with READ access.
OK, thanks everyone (perhaps it would make sense to clarify this in the
manual).
I'm willing to see some details: version, query, explain analyze.
8.0.0
Query while the box is idle:
explain analyze select count(*) from fr_offer o, fr_merchant m where idxfti
@@ to_tsquery('ranz & mc') and eur >= 70 and m.m_id=o.m_id;
Aggregate (cost=2197.48..2197.48 rows=1 width=0) (actual time=88.052..88.054
rows=1 loops=1)
-> Merge Join (cost=2157.42..2196.32 rows=461 width=0) (actual
time=88.012..88.033 rows=3 loops=1)
Merge Cond: ("outer".m_id = "inner".m_id)
-> Index Scan using fr_merchant_pkey on fr_merchant m
(cost=0.00..29.97 rows=810 width=4) (actual time=0.041..1.233 rows=523
loops=1)
-> Sort (cost=2157.42..2158.57 rows=461 width=4) (actual
time=85.779..85.783 rows=3 loops=1)
Sort Key: o.m_id
-> Index Scan using idxfti_idx on fr_offer o
(cost=0.00..2137.02 rows=461 width=4) (actual time=77.957..85.754 rows=3
loops=1)
Index Cond: (idxfti @@ '\'ranz\' & \'mc\''::tsquery)
Filter: (eur >= 70::double precision)
Total runtime: 88.131 ms
now, while using apachebench (-c10), "top" says this:
Cpu0 : 15.3% us, 10.0% sy, 0.0% ni, 74.7% id, 0.0% wa, 0.0% hi, 0.0% si
Cpu1 : 13.3% us, 11.6% sy, 0.0% ni, 75.1% id, 0.0% wa, 0.0% hi, 0.0% si
Cpu2 : 16.9% us, 9.6% sy, 0.0% ni, 73.4% id, 0.0% wa, 0.0% hi, 0.0% si
Cpu3 : 18.7% us, 14.0% sy, 0.0% ni, 67.0% id, 0.0% wa, 0.0% hi, 0.3% si
(this is with shared_buffers = 2000; a larger setting makes almost no
difference for overall performance: although according to "top" system time
goes to ~0 and user time to ~25%, the system still stays 70-75% idle)
vmstat:
r b swpd free buff cache si so bi bo in cs us sy id
wa
2 0 0 8654316 64908 4177136 0 0 56 35 279 286 5 1 94
0
2 0 0 8646188 64908 4177136 0 0 0 0 1156 2982 15 10 75
0
2 0 0 8658412 64908 4177136 0 0 0 0 1358 3098 19 11 70
0
1 0 0 8646508 64908 4177136 0 0 0 104 1145 2070 13 12 75
0
so the script's execution speed is apparently not limited by the CPUs.
The query execution times go up like this while apachebench is running (and
the system is 75% idle):
Aggregate (cost=2197.48..2197.48 rows=1 width=0) (actual
time=952.661..952.663 rows=1 loops=1)
-> Merge Join (cost=2157.42..2196.32 rows=461 width=0) (actual
time=952.621..952.641 rows=3 loops=1)
Merge Cond: ("outer".m_id = "inner".m_id)
-> Index Scan using fr_merchant_pkey on fr_merchant m
(cost=0.00..29.97 rows=810 width=4) (actual time=2.078..3.338 rows=523
loops=1)
-> Sort (cost=2157.42..2158.57 rows=461 width=4) (actual
time=948.345..948.348 rows=3 loops=1)
Sort Key: o.m_id
-> Index Scan using idxfti_idx on fr_offer o
(cost=0.00..2137.02 rows=461 width=4) (actual time=875.643..948.301 rows=3
loops=1)
Index Cond: (idxfti @@ '\'ranz\' & \'mc\''::tsquery)
Filter: (eur >= 70::double precision)
Total runtime: 952.764 ms
I can't seem to find out where the bottleneck is, but it doesn't seem to be
CPU or disk. "top" shows that postgres processes are frequently in this
state:
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ WCHAN COMMAND
6701 postgres 16 0 204m 58m 56m S 9.3 0.2 0:06.96 semtimedo
^^^^^^^^^
postmaste
Any hints are appreciated...
Regards,
Marinos
Regards,
Oleg
_____________________________________________________________
Oleg Bartunov, sci.researcher, hostmaster of AstroNet,
Sternberg Astronomical Institute, Moscow University (Russia)
Internet: oleg@sai.msu.su, http://www.sai.msu.su/~megera/
phone: +007(095)939-16-83, +007(095)939-23-83
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