Re: Very poor read performance, query independent

Igor,

The 1st clause of the where statement won't select addresses the same way
as the one I wrote using the extension for IPv6 and IPv6 data types.

flowstimestamp is a view:
flows=# \d+ flowstimestamp
View "public.flowstimestamp"
Column | Type | Modifiers | Storage | Description
-------------+--------------------------+-----------+---------+-------------
flow_id | bigint | | plain |
unix_secs | bigint | | plain |
unix_nsecs | bigint | | plain |
sysuptime | bigint | | plain |
exaddr | ip4 | | plain |
dpkts | integer | | plain |
doctets | bigint | | plain |
first | bigint | | plain |
last | bigint | | plain |
engine_type | smallint | | plain |
engine_id | smallint | | plain |
srcaddr | ip4 | | plain |
dstaddr | ip4 | | plain |
nexthop | ip4 | | plain |
input | integer | | plain |
output | integer | | plain |
srcport | integer | | plain |
dstport | integer | | plain |
prot | smallint | | plain |
tos | smallint | | plain |
tcp_flags | smallint | | plain |
src_mask | smallint | | plain |
dst_mask | smallint | | plain |
src_as | integer | | plain |
dst_as | integer | | plain |
timestamp | timestamp with time zone | | plain |
View definition:
SELECT flows.flow_id,
flows.unix_secs,
flows.unix_nsecs,
flows.sysuptime,
flows.exaddr,
flows.dpkts,
flows.doctets,
flows.first,
flows.last,
flows.engine_type,
flows.engine_id,
flows.srcaddr,
flows.dstaddr,
flows.nexthop,
flows.input,
flows.output,
flows.srcport,
flows.dstport,
flows.prot,
flows.tos,
flows.tcp_flags,
flows.src_mask,
flows.dst_mask,
flows.src_as,
flows.dst_as,
to_timestamp((flows.unix_secs + flows.unix_nsecs / 1000000000)::double
precision) AS "timestamp"
FROM flows;

And it can use the indexes of flows:
Indexes:
"flows_pkey" PRIMARY KEY, btree (flow_id)
"flows_dstaddr_dstport" btree (dstaddr, dstport)
"flows_srcaddr_dstaddr_idx" btree (srcaddr, dstaddr)
"flows_srcaddr_srcport" btree (srcaddr, srcport)
"flows_srcport_dstport_idx" btree (srcport, dstport)

Thanks!

Charles

On Fri, Jul 14, 2017 at 10:18 PM, Igor Neyman <ineyman(at)perceptron(dot)com>
wrote:

>
>
>
>
> *From:* pgsql-performance-owner(at)postgresql(dot)org [mailto:pgsql-performance-
> owner(at)postgresql(dot)org] *On Behalf Of *Igor Neyman
> *Sent:* Friday, July 14, 2017 3:13 PM
> *To:* Charles Nadeau <charles(dot)nadeau(at)gmail(dot)com>
>
> *Cc:* Jeff Janes <jeff(dot)janes(at)gmail(dot)com>; pgsql-performance(at)postgresql(dot)org
> *Subject:* Re: [PERFORM] Very poor read performance, query independent
>
>
>
> *From:* Charles Nadeau [mailto:charles(dot)nadeau(at)gmail(dot)com
> <charles(dot)nadeau(at)gmail(dot)com>]
> *Sent:* Friday, July 14, 2017 11:35 AM
> *To:* Igor Neyman <ineyman(at)perceptron(dot)com>
> *Cc:* Jeff Janes <jeff(dot)janes(at)gmail(dot)com>; pgsql-performance(at)postgresql(dot)org
> *Subject:* Re: [PERFORM] Very poor read performance, query independent
>
>
>
> Igor,
>
>
>
> Initially temp_buffer was left to its default value (8MB). Watching the
> content of the directory that stores the temporary files, I found that I
> need at most 21GB of temporary files space. Should I set temp_buffer to
> 21GB?
>
> Here is the explain you requested with work_mem set to 6GB:
>
> flows=# set work_mem='6GB';
>
> SET
>
> flows=# explain (analyze, buffers) SELECT DISTINCT
>
> srcaddr,
>
> dstaddr,
>
> dstport,
>
> COUNT(*) AS conversation,
>
> SUM(doctets) / 1024 / 1024 AS mbytes
>
> FROM
>
> flowscompact,
>
> mynetworks
>
> WHERE
>
> mynetworks.ipaddr >>= flowscompact.srcaddr
>
> AND dstaddr IN
>
> (
>
> SELECT
>
> dstaddr
>
> FROM
>
> dstexterne
>
> )
>
> GROUP BY
>
> srcaddr,
>
> dstaddr,
>
> dstport
>
> ORDER BY
>
> mbytes DESC LIMIT 50;
>
>
> QUERY PLAN
>
>
> ------------------------------------------------------------
> ------------------------------------------------------------
> ------------------------------------------------------------------------
>
> Limit (cost=48135680.07..48135680.22 rows=50 width=52) (actual
> time=2227678.196..2227678.223 rows=50 loops=1)
>
> Buffers: shared hit=728798038 read=82974833, temp read=381154
> written=381154
>
> -> Unique (cost=48135680.07..48143613.62 rows=2644514 width=52)
> (actual time=2227678.194..2227678.217 rows=50 loops=1)
>
> Buffers: shared hit=728798038 read=82974833, temp read=381154
> written=381154
>
> -> Sort (cost=48135680.07..48137002.33 rows=2644514 width=52)
> (actual time=2227678.192..2227678.202 rows=50 loops=1)
>
> Sort Key: (((sum(flows.doctets) / '1024'::numeric) /
> '1024'::numeric)) DESC, flows.srcaddr, flows.dstaddr, flows.dstport,
> (count(*))
>
> Sort Method: quicksort Memory: 654395kB
>
> Buffers: shared hit=728798038 read=82974833, temp
> read=381154 written=381154
>
> -> GroupAggregate (cost=48059426.65..48079260.50
> rows=2644514 width=52) (actual time=2167909.030..2211446.192 rows=5859671
> loops=1)
>
> Group Key: flows.srcaddr, flows.dstaddr, flows.dstport
>
> Buffers: shared hit=728798038 read=82974833, temp
> read=381154 written=381154
>
> -> Sort (cost=48059426.65..48060748.90
> rows=2644514 width=20) (actual time=2167896.815..2189107.205 rows=91745640
> loops=1)
>
> Sort Key: flows.srcaddr, flows.dstaddr,
> flows.dstport
>
> Sort Method: external merge Disk: 3049216kB
>
> Buffers: shared hit=728798038 read=82974833,
> temp read=381154 written=381154
>
> -> Gather (cost=30060688.07..48003007.07
> rows=2644514 width=20) (actual time=1268989.000..1991357.232 rows=91745640
> loops=1)
>
> Workers Planned: 12
>
> Workers Launched: 12
>
> Buffers: shared hit=728798037
> read=82974833
>
> -> Hash Semi Join
> (cost=30059688.07..47951761.31 rows=220376 width=20) (actual
> time=1268845.181..2007864.725 rows=7057357 loops=13)
>
> Hash Cond: (flows.dstaddr =
> flows_1.dstaddr)
>
> Buffers: shared hit=728795193
> read=82974833
>
> -> Nested Loop
> (cost=0.03..17891246.86 rows=220376 width=20) (actual
> time=0.207..723790.283 rows=37910370 loops=13)
>
> Buffers: shared hit=590692229
> read=14991777
>
> -> Parallel Seq Scan on
> flows (cost=0.00..16018049.14 rows=55094048 width=20) (actual
> time=0.152..566179.117 rows=45371630 loops=13)
>
> Buffers: shared
> hit=860990 read=14991777
>
> -> Index Only Scan using
> mynetworks_ipaddr_idx on mynetworks (cost=0.03..0.03 rows=1 width=8)
> (actual time=0.002..0.002 rows=1 loops=589831190)
>
> Index Cond: (ipaddr >>=
> (flows.srcaddr)::ip4r)
>
> Heap Fetches: 0
>
> Buffers: shared
> hit=589831203
>
> -> Hash
> (cost=30059641.47..30059641.47 rows=13305 width=4) (actual
> time=1268811.101..1268811.101 rows=3803508 loops=13)
>
> Buckets: 4194304 (originally
> 16384) Batches: 1 (originally 1) Memory Usage: 166486kB
>
> Buffers: shared hit=138102964
> read=67983056
>
> -> HashAggregate
> (cost=30059561.64..30059601.56 rows=13305 width=4) (actual
> time=1265248.165..1267432.083 rows=3803508 loops=13)
>
> Group Key:
> flows_1.dstaddr
>
> Buffers: shared
> hit=138102964 read=67983056
>
> -> Nested Loop Anti
> Join (cost=0.00..29729327.92 rows=660467447 width=4) (actual
> time=0.389..1201072.707 rows=125838232 loops=13)
>
> Join Filter:
> (mynetworks_1.ipaddr >> (flows_1.dstaddr)::ip4r)
>
> Rows Removed by
> Join Filter: 503353617
>
> Buffers: shared
> hit=138102964 read=67983056
>
> -> Seq Scan on
> flows flows_1 (cost=0.00..17836152.73 rows=661128576 width=4) (actual
> time=0.322..343152.274 rows=589831190 loops=13)
>
> Buffers:
> shared hit=138102915 read=67983056
>
> -> Materialize
> (cost=0.00..1.02 rows=4 width=8) (actual time=0.000..0.000 rows=2
> loops=7667805470)
>
> Buffers:
> shared hit=13
>
> -> Seq
> Scan on mynetworks mynetworks_1 (cost=0.00..1.01 rows=4 width=8) (actual
> time=0.006..0.007 rows=4 loops=13)
>
>
> Buffers: shared hit=13
>
> Planning time: 0.941 ms
>
> Execution time: 2228345.171 ms
>
> (48 rows)
>
>
>
> With a work_mem at 6GB, I noticed that for the first 20 minutes the query
> was running, the i/o wait was much lower, hovering aroun 3% then it jumped
> 45% until almost the end of the query.
>
>
>
> flowscompact and dstexterne are actually views. I use views to simplify
> query writing and to "abstract" queries that are use often in other
> queries. flowscompact is a view built on table flows (having about 590
> million rows), it only keeps the most often used fields.
>
> flows=# \d+ flowscompact;
>
> View "public.flowscompact"
>
> Column | Type | Modifiers | Storage | Description
>
> -----------+--------------------------+-----------+---------+-------------
>
> flow_id | bigint | | plain |
>
> sysuptime | bigint | | plain |
>
> exaddr | ip4 | | plain |
>
> dpkts | integer | | plain |
>
> doctets | bigint | | plain |
>
> first | bigint | | plain |
>
> last | bigint | | plain |
>
> srcaddr | ip4 | | plain |
>
> dstaddr | ip4 | | plain |
>
> srcport | integer | | plain |
>
> dstport | integer | | plain |
>
> prot | smallint | | plain |
>
> tos | smallint | | plain |
>
> tcp_flags | smallint | | plain |
>
> timestamp | timestamp with time zone | | plain |
>
> View definition:
>
> SELECT flowstimestamp.flow_id,
>
> flowstimestamp.sysuptime,
>
> flowstimestamp.exaddr,
>
> flowstimestamp.dpkts,
>
> flowstimestamp.doctets,
>
> flowstimestamp.first,
>
> flowstimestamp.last,
>
> flowstimestamp.srcaddr,
>
> flowstimestamp.dstaddr,
>
> flowstimestamp.srcport,
>
> flowstimestamp.dstport,
>
> flowstimestamp.prot,
>
> flowstimestamp.tos,
>
> flowstimestamp.tcp_flags,
>
> flowstimestamp."timestamp"
>
> FROM flowstimestamp;
>
> mynetworks is a table having one column and 4 rows; it contains a list of
> our network networks:
>
> flows=# select * from mynetworks;
>
> ipaddr
>
> ----------------
>
> 192.168.0.0/24
>
> 10.112.12.0/30
>
> 10.112.12.4/30
>
> 10.112.12.8/30
>
> (4 row)
>
> flows=# \d+ mynetworks;
>
> Table "public.mynetworks"
>
> Column | Type | Modifiers | Storage | Stats target | Description
>
> --------+------+-----------+---------+--------------+-------------
>
> ipaddr | ip4r | | plain | |
>
> Indexes:
>
> "mynetworks_ipaddr_idx" gist (ipaddr)
>
> dstexterne is a view listing all the destination IPv4 addresses not inside
> our network; it has one column and 3.8 million rows.
>
> flows=# \d+ dstexterne;
>
> View "public.dstexterne"
>
> Column | Type | Modifiers | Storage | Description
>
> ---------+------+-----------+---------+-------------
>
> dstaddr | ip4 | | plain |
>
> View definition:
>
> SELECT DISTINCT flowscompact.dstaddr
>
> FROM flowscompact
>
> LEFT JOIN mynetworks ON mynetworks.ipaddr >>
> flowscompact.dstaddr::ip4r
>
> WHERE mynetworks.ipaddr IS NULL;
>
> Thanks!
>
>
>
> Charles
>
>
>
> Charles,
>
>
>
> Also, let’s try to simplify your query and see if it performs better.
>
> You are grouping by srcaddr, dstaddr, dstport, that makes DISTINCT not
> needed.
>
> And after simplifying WHERE clause (let me know if the result is not what
> you want), the query looks like:
>
>
>
> SELECT srcaddr, dstaddr, dstport,
>
> COUNT(*) AS conversation,
>
> SUM(doctets) / 1024 / 1024 AS mbytes
>
> FROM flowscompact
>
> WHERE srcaddr IN (SELECT ipaddr FROM mynetworks)
>
> AND dstaddr NOT IN (SELECT ipaddr FROM mynetworks)
>
> GROUP BY srcaddr, dstaddr, dstport
>
> ORDER BY mbytes DESC
>
> LIMIT 50;
>
>
>
> Now, you didn’t provide the definition of flowstimestamp table.
>
> If this table doesn’t have an index on (srcaddr, dstaddr, dstport)
> creating one should help (I think).
>
>
>
> Igor
>
>
>
>
>
>
>

--
Charles Nadeau Ph.D.
http://charlesnadeau.blogspot.com/