Thread: Performance Problem with postgresql 9.03, 8GB RAM,Quadcore Processor Server--Need help!!!!!!!

I have Quadcore server with 8GB RAM

vendor_id       : GenuineIntel
cpu family      : 6
model           : 44
model name      : Intel(R) Xeon(R) CPU           E5607  @ 2.27GHz
stepping        : 2
cpu MHz         : 1197.000
cache size      : 8192 KB


MemTotal:        8148636 kB
MemFree:         4989116 kB
Buffers:            8464 kB
Cached:          2565456 kB
SwapCached:        81196 kB
Active:          2003796 kB
Inactive:         843896 kB
Active(anon):    1826176 kB
Inactive(anon):   405964 kB
Active(file):     177620 kB
Inactive(file):   437932 kB
Unevictable:           0 kB
Mlocked:               0 kB
SwapTotal:      16779260 kB
SwapFree:       16303356 kB
Dirty:              1400 kB
Writeback:             0 kB
AnonPages:        208260 kB
Mapped:          1092008 kB
Shmem:           1958368 kB
Slab:             224964 kB
SReclaimable:      60136 kB
SUnreclaim:       164828 kB
KernelStack:        2864 kB
PageTables:        35684 kB
NFS_Unstable:          0 kB
Bounce:                0 kB
WritebackTmp:          0 kB
CommitLimit:    20853576 kB
Committed_AS:    3672176 kB
VmallocTotal:   34359738367 kB
VmallocUsed:      303292 kB
VmallocChunk:   34359429308 kB
HardwareCorrupted:     0 kB
HugePages_Total:       0
HugePages_Free:        0
HugePages_Rsvd:        0
HugePages_Surp:        0
Hugepagesize:       2048 kB
DirectMap4k:        6144 kB
DirectMap2M:     2082816 kB
DirectMap1G:     6291456 kB

My database size is

pg_size_pretty
----------------
 21 GB

i have one table which has data more than 160500460 rows almost.......and i have partioned with yearwise in different schemas

 stk_source
                                            Table "_100410.stk_source"
        Column         |   Type    |                      Modifiers                      | Storage  | Description
-----------------------+-----------+-----------------------------------------------------+----------+-------------
 source_id             | integer   | not null default nextval('source_id_seq'::regclass) | plain    |
 stock_id              | integer   |                                                     | plain    |
 source_detail         | integer[] |                                                     | extended |
 transaction_reference | integer   |                                                     | plain    |
 is_user_set           | boolean   | default false                                       | plain    |
Triggers:
    insert_stk_source_trigger BEFORE INSERT ON stk_source FOR EACH ROW EXECUTE PROCEDURE stk_source_insert_trigger()
Child tables: _100410_200809.stk_source,
              _100410_200910.stk_source,
              _100410_201011.stk_source,
              _100410_201112.stk_source
Has OIDs: yes

Also have indexes

ss_source_id_pk" PRIMARY KEY, btree (source_id)
"stk_source_stock_id_idx" btree (stock_id)


First two years data is very less so no issues

and next two years table size is 2GB & 10 GB respectively.

EXPLAIN select * from stk_source ;
                                     QUERY PLAN                                     
-------------------------------------------------------------------------------------
 Result  (cost=0.00..6575755.39 rows=163132513 width=42)
   ->  Append  (cost=0.00..6575755.39 rows=163132513 width=42)
         ->  Seq Scan on stk_source  (cost=0.00..42.40 rows=1080 width=45)
         ->  Seq Scan on stk_source  (cost=0.00..20928.37 rows=519179 width=42)
         ->  Seq Scan on stk_source  (cost=0.00..85125.82 rows=2111794 width=42)
         ->  Seq Scan on stk_source  (cost=0.00..6469658.80 rows=160500460 width=42)


because of this table my total database performance got affected i want to optimize the settings by reading the below blogs i have changed some configurations but no use still sytem is slow
http://comments.gmane.org/gmane.comp.db.postgresql.performance/29561
 
Actually we are using one PHP application in that we have used Postgresql 9.0.3 database.The server is accessing 40 -50 users daily....so want to have more performance....my config details are below....

Could any one help how to tune the settings for better performance???

Thanks in advance..........

# - Memory -

shared_buffers = 2GB                    # min 128kB
                                                   # (change requires restart)
#temp_buffers = 8MB                     # min 800kB
max_prepared_transactions = 0       # zero disables the feature
                                                       # (change requires restart)

# Note:  Increasing max_prepared_transactions costs ~600 bytes of shared memory
# per transaction slot, plus lock space (see max_locks_per_transaction).
# It is not advisable to set max_prepared_transactions nonzero unless you
# actively intend to use prepared transactions.


work_mem = 48MB                         # min 64kB
maintenance_work_mem = 256MB            # min 1MB
max_stack_depth = 6MB                   # min 100kB


# - Planner Cost Constants -

seq_page_cost = 1.0                     # measured on an arbitrary scale
random_page_cost = 3.0                  # same scale as above
cpu_tuple_cost = 0.03                   # same scale as above
#cpu_index_tuple_cost = 0.005           # same scale as above
#cpu_operator_cost = 0.0025             # same scale as above
effective_cache_size = 4GB
------------------------------------------------------------------------
free -t -m
             total       used       free     shared    buffers     cached
Mem:          7957       3111       4845          0         10       2670
-/+ buffers/cache:        430       7527
Swap:        16385        458      15927
Total:       24343       3570      20773

ipcs -l

------ Shared Memory Limits --------
max number of segments = 4096
max seg size (kbytes) = 18014398509481983
max total shared memory (kbytes) = 4611686018427386880
min seg size (bytes) = 1

------ Semaphore Limits --------
max number of arrays = 1024
max semaphores per array = 250
max semaphores system wide = 256000
max ops per semop call = 32
semaphore max value = 32767

------ Messages Limits --------
max queues system wide = 3977
max size of message (bytes) = 65536
default max size of queue (bytes) = 65536


--
Regards
Mohamed Hashim.N
Mobile:09894587678

what sort of queries you are running against it ? the select * from..
is not really (hopefully) a query you are running from your php app.

Actually we are using various views and functions to get the info for reporting purpose in that views or functions we have used or joined the above table mentioned.

I thought of will get reply from any one from the lists so only i put anyway i will continue with only pgsql-performance mailing lists.

Regards
Hashim




--
Regards
Mohamed Hashim.N
Mobile:09894587678

On 28 October 2011 09:02, Mohamed Hashim <nmdhashim@gmail.com> wrote:
> EXPLAIN select * from stk_source ;
>                                      QUERY
> PLAN
> -------------------------------------------------------------------------------------
>  Result  (cost=0.00..6575755.39 rows=163132513 width=42)
>    ->  Append  (cost=0.00..6575755.39 rows=163132513 width=42)
>          ->  Seq Scan on stk_source  (cost=0.00..42.40 rows=1080 width=45)
>          ->  Seq Scan on stk_source  (cost=0.00..20928.37 rows=519179
> width=42)
>          ->  Seq Scan on stk_source  (cost=0.00..85125.82 rows=2111794
> width=42)
>          ->  Seq Scan on stk_source  (cost=0.00..6469658.80 rows=160500460
> width=42)

That plan gives you the best possible performance given your query.
Your example probably doesn't fit the problem you're investigating.

--
If you can't see the forest for the trees,
Cut the trees and you'll see there is no forest.

Thanks Alban & Gregg.


i will describe little more about that table

• We are using PHP application with Apache server & Postgresql 9.0.3 in a dedicated server.
• stk_source table is mainly used to track the transactions from parent to child

                               Table "_100410.stk_source"
        Column         |   Type    |                      Modifiers                     
-----------------------+-----------+-----------------------------------------------------
 source_id             | integer   | not null default nextval('source_id_seq'::regclass)
 stock_id              | integer   |
 source_detail         | integer[] |
 transaction_reference | integer   |
 is_user_set           | boolean   | default false


We store transaction_type and transaction_id in source_detail column which is an interger array for each transactions

We use various functions to get the info based on transaction type

For eg:

In function to get the batch details we have used as

FOR batch_id_rec in select distinct(batch_id) from order_status_batches osb join batch_status_stock bss on osb.status_id=bss.batch_status_id where stock_id in (select source_detail[2] from stk_source where stock_id IN (SELECT std_i.stock_id                                                                                                                                     
        FROM order_details_shipments ods                                                                                                                                                       
        JOIN shipment_pack_stock sps ON sps.pack_id=ods.pack_id AND ods.order_id=sps.order_id AND ods.item_id=sps.item_id
        JOIN stock_transaction_detail_106 std ON std.transaction_id=sps.transaction_id
        JOIN stock_transaction_detail_106 std_i ON std.stock_id = std_i.stock_id AND std_i.transaction_type = 'i'::bpchar
        WHERE shipment_item_id=$1 ) and source_detail[1]=3) LOOP

...............................

................................

......................................

Similarly we have used in php pages and views

SELECT abd.bill_no as bill_no,to_char(abd.bill_date,'dd/mm/yyyy') AS date,mp.product_desc as product_desc,std.quantity,std.area,rip.price AS rate,
FROM acc_bill_items_106 abi
    JOIN acc_bill_details_106_table abd ON abd.bill_id=abi.bill_id AND abd.bill_status='act'
    JOIN stk_source_table ss ON ss.source_detail[2]=abi.item_id and ss.source_detail[1]=1
    JOIN stock_transaction_detail_106_table std ON std.stock_id=ss.stock_id
    JOIN stock_details_106_table sd106 ON sd106.stock_id=std.stock_id
    JOIN master_product_106_table mp ON mp.product_id= sd106.product_id
    JOIN receipt_item_price_106_table rip ON rip.receipt_item_id=abi.item_id
    WHERE abi.bill_id=$bill_id AND std.transaction_type='o'  ;

So where ever we have JOIN or used in functions the performance is very low some times query returns results takes more than 45 mints.

Normally if we fetch Select * from some_table..........it returns very fast because it has less records.

But when i put Select * from stk_source or to find the actual_cost

EXPLAIN ANALYZE SELECT * FROM stk_source;

i couln't able to retrieve the planner details waited for more than 50 to 60 mints

so question is in spite of having good server with high configuration and also changed the postgresql configuration settings then why the system is crawling?


What are the other parameters have to look out or what are the other config settings to be change to have the best performance??

Kindly help to sort out this problem......


Thanks in advance..................!!!!!!

Regards
Hashim




 





--
Regards
Mohamed Hashim.N
Mobile:09894587678

Any idea or suggestions how to improve my database best performance.................???

Regards
Hashim




--
Regards
Mohamed Hashim.N
Mobile:09894587678

Hi Hashim,

After I upgraded from Postgres 8.3/8.4 to 9.0 I had all sorts of problems with queries with many joins. Queries that used to take 1ms suddenly take half a minute for no apparent reason.

I have 72GB which I think makes the planner go bonkers and be too eager doing a seq scan. I tried to compensate with ridiculously low cpu_index_tuple_cost but it had little effect.

If I were you, I would try to remove some of the joined tables and see what happens. When does it start to run very slowly? How does the plan look right before it's super slow?


One workaround I've done is if something looking like this....

select
    ...
from
    table_linking_massive_table tlmt
   ,massive_table mt
   ,some_table1 st1
   ,some_table2 st2
   ,some_table3 st3
   ,some_table4 st4
where
    tlmt.group_id = 123223 AND
    mt.id = tmlt.massive_table AND
    st1.massive_table = mt.id AND
    st2.massive_table = mt.id AND
    st3.massive_table = mt.id AND
    st4.massive_table = mt.id
   
...suddenly gets slow, it has helped to rewrite it as....

select
    ...
from
    (
        select
            ...
        from
            table_linking_massive_table tlmt
           ,massive_table mt
        where
            tlmt.group_id = 123223 AND
            mt.id = tmlt.massive_table AND
    ) as mt
   ,some_table1 st1
   ,some_table2 st2
   ,some_table3 st3
   ,some_table4 st4
where
    tlmt.group_id = 123223 AND
    mt.id = tmlt.massive_table AND
    st1.massive_table = mt.id AND
    st2.massive_table = mt.id AND
    st3.massive_table = mt.id AND
    st4.massive_table = mt.id

This seems to force Postgres to evaluate the mt subselect first and not get ideas about how to join. It was a few years ago since I used Oracle but if I remember correctly Oracle looked at the order of the things in the where section. In this example Oracle would be encourage to use tlmt as base table and take it from there. It doesn't seem to me that Postgres cares about this order. Not caring would possibly be more forgiving with automatically generated sql but it also implies the planner always makes the best decisions which it obviously is not. I might be talking rubbish here, these are my empirical observations.

I'm sure you'll get better answers, but this is what I've done.

I assume you have done your analyze & indexing correctly etc.

Best regards,
Marcus

On 11/1/11 4:03 , Mohamed Hashim wrote:

Any idea or suggestions how to improve my database best performance.................???

Regards
Hashim

On Sat, Oct 29, 2011 at 9:40 AM, Mohamed Hashim <nmdhashim@gmail.com> wrote:

Thanks Alban & Gregg.


i will describe little more about that table

• We are using PHP application with Apache server & Postgresql 9.0.3 in a dedicated server.
• stk_source table is mainly used to track the transactions from parent to child

                               Table "_100410.stk_source"
        Column         |   Type    |                      Modifiers                     

-----------------------+-----------+-----------------------------------------------------

 source_id             | integer   | not null default nextval('source_id_seq'::regclass)

 stock_id              | integer   |
 source_detail         | integer[] |
 transaction_reference | integer   |
 is_user_set           | boolean   | default false


We store transaction_type and transaction_id in source_detail column which is an interger array for each transactions

We use various functions to get the info based on transaction type

For eg:

In function to get the batch details we have used as

FOR batch_id_rec in select distinct(batch_id) from order_status_batches osb join batch_status_stock bss on osb.status_id=bss.batch_status_id where stock_id in (select source_detail[2] from stk_source where stock_id IN (SELECT std_i.stock_id                                                                                                                                     
        FROM order_details_shipments ods                                                                                                                                                       
        JOIN shipment_pack_stock sps ON sps.pack_id=ods.pack_id AND ods.order_id=sps.order_id AND ods.item_id=sps.item_id
        JOIN stock_transaction_detail_106 std ON std.transaction_id=sps.transaction_id
        JOIN stock_transaction_detail_106 std_i ON std.stock_id = std_i.stock_id AND std_i.transaction_type = 'i'::bpchar
        WHERE shipment_item_id=$1 ) and source_detail[1]=3) LOOP

...............................

................................

......................................

Similarly we have used in php pages and views

SELECT abd.bill_no as bill_no,to_char(abd.bill_date,'dd/mm/yyyy') AS date,mp.product_desc as product_desc,std.quantity,std.area,rip.price AS rate,
FROM acc_bill_items_106 abi
    JOIN acc_bill_details_106_table abd ON abd.bill_id=abi.bill_id AND abd.bill_status='act'
    JOIN stk_source_table ss ON ss.source_detail[2]=abi.item_id and ss.source_detail[1]=1
    JOIN stock_transaction_detail_106_table std ON std.stock_id=ss.stock_id
    JOIN stock_details_106_table sd106 ON sd106.stock_id=std.stock_id
    JOIN master_product_106_table mp ON mp.product_id= sd106.product_id
    JOIN receipt_item_price_106_table rip ON rip.receipt_item_id=abi.item_id
    WHERE abi.bill_id=$bill_id AND std.transaction_type='o'  ;

So where ever we have JOIN or used in functions the performance is very low some times query returns results takes more than 45 mints.

Normally if we fetch Select * from some_table..........it returns very fast because it has less records.

But when i put Select * from stk_source or to find the actual_cost

EXPLAIN ANALYZE SELECT * FROM stk_source;

i couln't able to retrieve the planner details waited for more than 50 to 60 mints

so question is in spite of having good server with high configuration and also changed the postgresql configuration settings then why the system is crawling?


What are the other parameters have to look out or what are the other config settings to be change to have the best performance??

Kindly help to sort out this problem......


Thanks in advance..................!!!!!!

Regards
Hashim

 

On Fri, Oct 28, 2011 at 5:07 PM, Alban Hertroys <haramrae@gmail.com> wrote:

On 28 October 2011 09:02, Mohamed Hashim <nmdhashim@gmail.com> wrote:
> EXPLAIN select * from stk_source ;
>                                      QUERY
> PLAN
> -------------------------------------------------------------------------------------
>  Result  (cost=0.00..6575755.39 rows=163132513 width=42)
>    ->  Append  (cost=0.00..6575755.39 rows=163132513 width=42)
>          ->  Seq Scan on stk_source  (cost=0.00..42.40 rows=1080 width=45)
>          ->  Seq Scan on stk_source  (cost=0.00..20928.37 rows=519179
> width=42)
>          ->  Seq Scan on stk_source  (cost=0.00..85125.82 rows=2111794
> width=42)
>          ->  Seq Scan on stk_source  (cost=0.00..6469658.80 rows=160500460
> width=42)

That plan gives you the best possible performance given your query.
Your example probably doesn't fit the problem you're investigating.

--
If you can't see the forest for the trees,
Cut the trees and you'll see there is no forest.

--
Regards
Mohamed Hashim.N
Mobile:09894587678

--
Regards
Mohamed Hashim.N
Mobile:09894587678

On Tue, Nov 01, 2011 at 08:33:51AM +0530, Mohamed Hashim wrote:
> Any idea or suggestions how to improve my database best
> performance.................???
>
> Regards
> Hashim
>
Hi Hashim,

Ignoring the description of your tables, you should probably try
updating to the latest release 9.0.5. You are two point releases
back and they really, really, really fix bugs in each release or
they do not bother releasing.

Regards,
Ken

On 1 Listopad 2011, 10:57, Marcus Engene wrote:
> Hi Hashim,
>
> One workaround I've done is if something looking like this....
>
> select
>      ...
> from
>      table_linking_massive_table tlmt
>     ,massive_table mt
>     ,some_table1 st1
>     ,some_table2 st2
>     ,some_table3 st3
>     ,some_table4 st4
> where
>      tlmt.group_id = 123223 AND
>      mt.id = tmlt.massive_table AND
>      st1.massive_table = mt.id AND
>      st2.massive_table = mt.id AND
>      st3.massive_table = mt.id AND
>      st4.massive_table = mt.id
>
> ...suddenly gets slow, it has helped to rewrite it as....
>
> select
>      ...
> from
>      (
>          select
>              ...
>          from
>              table_linking_massive_table tlmt
>             ,massive_table mt
>          where
>              tlmt.group_id = 123223 AND
>              mt.id = tmlt.massive_table AND
>      ) as mt
>     ,some_table1 st1
>     ,some_table2 st2
>     ,some_table3 st3
>     ,some_table4 st4
> where
>      tlmt.group_id = 123223 AND
>      mt.id = tmlt.massive_table AND
>      st1.massive_table = mt.id AND
>      st2.massive_table = mt.id AND
>      st3.massive_table = mt.id AND
>      st4.massive_table = mt.id
>

Can you please post EXPLAIN ANALYZE of those queries? It's difficult to
see what's wrong when we don't know the plan (and the actual stats
gathered during execution). Use explain.depesz.com to post the output.

Tomas

Marcus Engene <mengpg2@engene.se> writes:
> After I upgraded from Postgres 8.3/8.4 to 9.0 I had all sorts of
> problems with queries with many joins. Queries that used to take 1ms
> suddenly take half a minute for no apparent reason.

Could we see a concrete test case, rather than hand waving?  If there's
really a problem in 9.0, it's impossible to fix it on so little detail.

> One workaround I've done is if something looking like this....

The only way that should make a difference is if the total number
of tables in the query exceeds from_collapse_limit (or maybe
join_collapse_limit, depending on exactly how you wrote the query).
Perhaps you'd been running with nonstandard values of those settings
in 8.x, and forgot to transfer them into the new DB?

            regards, tom lane

Dear All

Thanks for your suggestions & replies.

The below are the sample query which i put for particular one bill_id

EXPLAIN ANALYZE SELECT abd.bill_no as bill_no,to_char(abd.bill_date,'dd/mm/yyyy') AS date,mp.product_desc as product_desc,std.quantity,std.area,rip.price AS rate
FROM acc_bill_items_106 abi
    JOIN acc_bill_details_106 abd ON abd.bill_id=abi.bill_id
    JOIN stk_source ss ON  ss.source_detail[1]=1 and ss.source_detail[2]=abi.item_id
    JOIN stock_transaction_detail_106 std ON std.stock_id=ss.stock_id
    JOIN stock_details_106 sd106 ON sd106.stock_id=std.stock_id
    JOIN master_product_106 mp ON mp.product_id= sd106.product_id
    JOIN receipt_item_price_106 rip ON rip.receipt_item_id=abi.item_id
    WHERE abi.bill_id=12680;


                                                                                    QUERY PLAN                                                                                    
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Nested Loop  (cost=0.00..7230339.59 rows=54369 width=39) (actual time=158156.895..158157.206 rows=1 loops=1)
   ->  Nested Loop  (cost=0.00..7149579.10 rows=8192 width=32) (actual time=158156.863..158157.172 rows=1 loops=1)
         ->  Nested Loop  (cost=0.00..7119922.60 rows=8192 width=27) (actual time=158156.855..158157.164 rows=1 loops=1)
               ->  Nested Loop  (cost=0.00..7086865.70 rows=8192 width=19) (actual time=158156.835..158157.143 rows=1 loops=1)
                     Join Filter: (abi.item_id = ss.source_detail[2])
                     ->  Nested Loop  (cost=0.00..604.54 rows=2 width=23) (actual time=2.782..2.786 rows=1 loops=1)
                           ->  Index Scan using acc_bill_details_106_pkey on acc_bill_details_106 abd  (cost=0.00..6.29 rows=1 width=12) (actual time=0.010..0.012 rows=1 loops=1)
                                 Index Cond: (bill_id = 12680)
                           ->  Nested Loop  (cost=0.00..598.19 rows=2 width=19) (actual time=2.770..2.772 rows=1 loops=1)
                                 Join Filter: (abi.item_id = rip.receipt_item_id)
                                 ->  Seq Scan on receipt_item_price_106 rip  (cost=0.00..162.48 rows=4216 width=11) (actual time=0.005..0.562 rows=4218 loops=1)
                                 ->  Materialize  (cost=0.00..140.59 rows=2 width=8) (actual time=0.000..0.000 rows=1 loops=4218)
                                       ->  Seq Scan on acc_bill_items_106 abi  (cost=0.00..140.58 rows=2 width=8) (actual time=0.412..0.412 rows=1 loops=1)
                                             Filter: (bill_id = 12680)
                     ->  Materialize  (cost=0.00..7024562.68 rows=819222 width=33) (actual time=0.035..153869.575 rows=19010943 loops=1)
                           ->  Append  (cost=0.00..7014065.57 rows=819222 width=33) (actual time=0.034..145403.828 rows=19010943 loops=1)
                                 ->  Seq Scan on stk_source ss  (cost=0.00..45.10 rows=5 width=36) (actual time=0.001..0.001 rows=0 loops=1)
                                       Filter: (source_detail[1] = 1)
                                 ->  Seq Scan on stk_source ss  (cost=0.00..22226.32 rows=2596 width=33) (actual time=0.033..118.019 rows=66356 loops=1)
                                       Filter: (source_detail[1] = 1)
                                 ->  Seq Scan on stk_source ss  (cost=0.00..90405.31 rows=10559 width=33) (actual time=0.010..490.712 rows=288779 loops=1)
                                       Filter: (source_detail[1] = 1)
                                 ->  Seq Scan on stk_source ss  (cost=0.00..6901388.84 rows=806062 width=33) (actual time=13.382..142493.302 rows=18655808 loops=1)
                                       Filter: (source_detail[1] = 1)
               ->  Index Scan using sd106_stock_id_idx on stock_details_106 sd106  (cost=0.00..4.00 rows=1 width=8) (actual time=0.014..0.014 rows=1 loops=1)
                     Index Cond: (sd106.stock_id = ss.stock_id)
         ->  Index Scan using master_product_pkey on master_product_106 mp  (cost=0.00..3.59 rows=1 width=13) (actual time=0.006..0.006 rows=1 loops=1)
               Index Cond: (mp.product_id = sd106.product_id)
   ->  Index Scan using std106_stock_id_idx on stock_transaction_detail_106 std  (cost=0.00..9.70 rows=4 width=19) (actual time=0.007..0.009 rows=1 loops=1)
         Index Cond: (std.stock_id = ss.stock_id)
 Total runtime: 158240.795 ms


http://explain.depesz.com/s/Tyc


Similarly i have used the queries on various details pages and views that too if i go for one month transactions its taking so much times.

I will try to upgrade to latest version and will try to tune more my queries so changing the conf settings wouldn't help for better performance??



Thanks & Regards
Hashim




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Regards
Mohamed Hashim.N
Mobile:09894587678

Mohamed Hashim <nmdhashim@gmail.com> writes:
> The below are the sample query which i put for particular one bill_id

> EXPLAIN ANALYZE SELECT abd.bill_no as
> bill_no,to_char(abd.bill_date,'dd/mm/yyyy') AS date,mp.product_desc as
> product_desc,std.quantity,std.area,rip.price AS rate
> FROM acc_bill_items_106 abi
>     JOIN acc_bill_details_106 abd ON abd.bill_id=abi.bill_id
>     JOIN stk_source ss ON  ss.source_detail[1]=1 and
> ss.source_detail[2]=abi.item_id
>     JOIN stock_transaction_detail_106 std ON std.stock_id=ss.stock_id
>     JOIN stock_details_106 sd106 ON sd106.stock_id=std.stock_id
>     JOIN master_product_106 mp ON mp.product_id= sd106.product_id
>     JOIN receipt_item_price_106 rip ON rip.receipt_item_id=abi.item_id
>     WHERE abi.bill_id=12680;

All the time seems to be going into the seqscan on stk_source and its
child tables.  It looks like it would help if "ss.source_detail[1]=1 and
ss.source_detail[2]=abi.item_id" were indexable (particularly the
latter).  Which probably means you need to rethink your data
representation.  Putting things that you need to index on into an array
is not a very good design.  I suppose you can do it if you're absolutely
set on it (functional indexes on (source_detail[1]) and (source_detail[2]))
but it appears to suck from a notational point of view too.  Six months
from now, when you look at this code, are you going to remember what's
the difference between source_detail[1] and source_detail[2]?  Not
without consulting your notes, I bet.

            regards, tom lane

Am 02.11.2011 08:12, schrieb Mohamed Hashim:

Dear All

Thanks for your suggestions & replies.

The below are the sample query which i put for particular one bill_id

EXPLAIN ANALYZE SELECT abd.bill_no as bill_no,to_char(abd.bill_date,'dd/mm/yyyy') AS date,mp.product_desc as product_desc,std.quantity,std.area,rip.price AS rate
FROM acc_bill_items_106 abi
    JOIN acc_bill_details_106 abd ON abd.bill_id=abi.bill_id
    JOIN stk_source ss ON  ss.source_detail[1]=1 and ss.source_detail[2]=abi.item_id
    JOIN stock_transaction_detail_106 std ON std.stock_id=ss.stock_id
    JOIN stock_details_106 sd106 ON sd106.stock_id=std.stock_id
    JOIN master_product_106 mp ON mp.product_id= sd106.product_id
    JOIN receipt_item_price_106 rip ON rip.receipt_item_id=abi.item_id
    WHERE abi.bill_id=12680;

First I would try this:
explain analyze select * from stk_source where source_detail[1] = 1;
explain analyze select * from stk_source where source_detail[2] = 12356;

Both times you'll get sequential scans, and that's the root of the problem. Oh, you mentioned that you use partitioning, but there seems to be no condition for that.

You should really rethink your database schema, at least try to pull out all indexable fields out of that int[] into columns, and use indices on those fields.

Regards
Mario

On 3 Listopad 2011, 16:02, Mario Weilguni wrote:
> Am 02.11.2011 08:12, schrieb Mohamed Hashim:
>> Dear All
>>
>> Thanks for your suggestions & replies.
>>
>> The below are the sample query which i put for particular one bill_id
>>
>> EXPLAIN ANALYZE SELECT abd.bill_no as
>> bill_no,to_char(abd.bill_date,'dd/mm/yyyy') AS date,mp.product_desc as
>> product_desc,std.quantity,std.area,rip.price AS rate
>> FROM acc_bill_items_106 abi
>>     JOIN acc_bill_details_106 abd ON abd.bill_id=abi.bill_id
>>     JOIN stk_source ss ON  ss.source_detail[1]=1 and
>> ss.source_detail[2]=abi.item_id
>>     JOIN stock_transaction_detail_106 std ON std.stock_id=ss.stock_id
>>     JOIN stock_details_106 sd106 ON sd106.stock_id=std.stock_id
>>     JOIN master_product_106 mp ON mp.product_id= sd106.product_id
>>     JOIN receipt_item_price_106 rip ON rip.receipt_item_id=abi.item_id
>>     WHERE abi.bill_id=12680;
>
> First I would try this:
> explain analyze select * from stk_source where source_detail[1] = 1;
> explain analyze select * from stk_source where source_detail[2] = 12356;
>
> Both times you'll get sequential scans, and that's the root of the
> problem. Oh, you mentioned that you use partitioning, but there seems to
> be no condition for that.
>
> You should really rethink your database schema, at least try to pull out
> all indexable fields out of that int[] into columns, and use indices on
> those fields.

No doubt about that, querying tables using conditions on array columns is
not the best direction in most cases, especially when those tables are
huge.

Still, the interesting part here is that the OP claims this worked just
fine in the older version and after an upgrade the performance suddenly
dropped. This could be caused by many things, and we're just guessing
because we don't have any plans from the old version.

Tomas

Am 03.11.2011 17:08, schrieb Tomas Vondra:
> On 3 Listopad 2011, 16:02, Mario Weilguni wrote:
> <snip>
> No doubt about that, querying tables using conditions on array columns is
> not the best direction in most cases, especially when those tables are
> huge.
>
> Still, the interesting part here is that the OP claims this worked just
> fine in the older version and after an upgrade the performance suddenly
> dropped. This could be caused by many things, and we're just guessing
> because we don't have any plans from the old version.
>
> Tomas
>
>

Not really, Mohamed always said he has 9.0.3, Marcus Engene wrote about
problems after the migration from 8.x to 9.x. Or did I miss something here?

Regards,
Mario

Hi all,

Thanks for all your responses.

Sorry for late response

Earlier we used Postgres8.3.10 with Desktop computer (as server) and configuration of the system (I2 core with 4GB RAM) and also the application was slow  i dint change any postgres config settings.

May be because of low config We thought the aplication is slow so we opted to go for higher configuration server(with RAID 1) which i mentioned earlier.

I thought the application will go fast but unfortunately there is no improvement so i tried to change the postgres config settings and trying to tune my queries wherever possible but still i was not able to..........improve the performance..


So will it helpful if we try GIST or GIN for integer array[] colum (source_detail) with enable_seqscan=off and default_statistics_target=1000?

Regards
Hashim






--
Regards
Mohamed Hashim.N
Mobile:09894587678

Hi all,

Thanks for all your responses.

Sorry for late response

Earlier we used Postgres8.3.10 with Desktop computer (as server) and configuration of the system (I2 core with 4GB RAM) and also the application was slow  i dint change any postgres config settings.

May be because of low config We thought the aplication is slow so we opted to go for higher configuration server(with RAID 1) which i mentioned earlier.

I thought the application will go fast but unfortunately there is no improvement so i tried to change the postgres config settings and trying to tune my queries wherever possible but still i was not able to..........improve the performance..


So will it helpful if we try GIST or GIN for integer array[] colum (source_detail) with enable_seqscan=off and default_statistics_target=1000?

Regards
Hashim

On Fri, Nov 4, 2011 at 1:37 AM, Mario Weilguni <roadrunner6@gmx.at> wrote:

Am 03.11.2011 17:08, schrieb Tomas Vondra:

On 3 Listopad 2011, 16:02, Mario Weilguni wrote:

<snip>

No doubt about that, querying tables using conditions on array columns is
not the best direction in most cases, especially when those tables are
huge.

Still, the interesting part here is that the OP claims this worked just
fine in the older version and after an upgrade the performance suddenly
dropped. This could be caused by many things, and we're just guessing
because we don't have any plans from the old version.

Tomas

Not really, Mohamed always said he has 9.0.3, Marcus Engene wrote about problems after the migration from 8.x to 9.x. Or did I miss something here?

Regards,
Mario

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Mohamed Hashim.N
Mobile:09894587678

On 8 Listopad 2011, 4:21, Mohamed Hashim wrote:
> Hi all,
>
> Thanks for all your responses.
>
> Sorry for late response
>
> Earlier we used Postgres8.3.10 with Desktop computer (as server) and
> configuration of the system (I2 core with 4GB RAM) and also the
> application
> was slow  i dint change any postgres config settings.
>
> May be because of low config We thought the aplication is slow so we opted
> to go for higher configuration server(with RAID 1) which i mentioned
> earlier.
>
> I thought the application will go fast but unfortunately there is no
> improvement so i tried to change the postgres config settings and trying
> to
> tune my queries wherever possible but still i was not able
> to..........improve the performance..

As Sam Gendler already wrote, we really can't help you until you post all
the relevant info. So far we've seen a single EXPLAIN ANALYZE output and
very vague description of the hardware.

We need to know more about the hardware and the basic config options
(shared buffers, effective cache size, work mem, etc.). We need to know
how much memory is actually available to PostgreSQL and page cache (how
much is consumed by the application - as I understand it it runs on the
same machine). We need to know what OS it's running on, and we need to see
iostat/vmstat output collected when the app is slow.

Please read this and perform the basic tuning (and let us know what values
you've used):

http://wiki.postgresql.org/wiki/Tuning_Your_PostgreSQL_Server

Also post

> So will it helpful if we try GIST or GIN for integer array[] colum
> (source_detail) with enable_seqscan=off and
> default_statistics_target=1000?

This is severely premature - it might help, but you should do the basic
tuning first. It might actually cause you more trouble. You've already
done this mistake - fixing something withouth veryfying it's actually a
problem - by requesting a RAID1 config. Don't do that mistake again.

Tomas

Hi Sam,Tomas

In my first post i have mentioned all how much shared (shared buffers, effective cache size, work mem, etc.) and my OS and hardware information and what are the basic settings i have changed

and regarding Explain analyze i gave one sample query because if i tune that particular table which has records almost 16crore i thought my problem will solve...

Regards
Hashim




--
Regards
Mohamed Hashim.N
Mobile:09894587678

On 8 Listopad 2011, 13:15, Mohamed Hashim wrote:
> Hi Sam,Tomas
>
> In my first post i have mentioned all how much shared (shared buffers,
> effective cache size, work mem, etc.) and my OS and hardware information
> and what are the basic settings i have changed

Sorry, I've missed that first message - the archive did not list it for
some reason.

> and regarding Explain analyze i gave one sample query because if i tune
> that particular table which has records almost 16crore i thought my
> problem
> will solve...

OK, so the problem is either the WHERE conditions referencing the array
column, or a bug in 9.0.x.

Can't help you with the upgrade issue, but using an array like this is a
bad design and will cause you all sorts of problems - why are you not
using regular columns, anyway?

I see you usually reference source_detail[1] - what is the expected
selectivity of this condition? What portion of the table matches it? How
many possible values are there?

And it does not make sense to me to partition by date when you're not
querying the data by date.

Try this (one by one):

1) CREATE INDEX src_idx ON stk_source(source_detail[1]) for each partition
2) add a regular column source_detail_val with the value of
source_detail[1] and create an index on it
3) repartition the table by source_detail[1] instead of date

Tomas

Am 08.11.2011 13:15, schrieb Mohamed Hashim:

Hi Sam,Tomas

In my first post i have mentioned all how much shared (shared buffers, effective cache size, work mem, etc.) and my OS and hardware information and what are the basic settings i have changed

and regarding Explain analyze i gave one sample query because if i tune that particular table which has records almost 16crore i thought my problem will solve...

Just curios, are those array items [1] and [2] just samples and you actually use more which are performance-related (used as condition)? If just those two are relevant I would change the schema to use real columns instead. And you seem to use partitioning, but you have no partition condition?

how about your harddisks??