Thread

1. Improving PostgreSQL insert performance

   Frits Jalvingh <jal@etc.to> — 2017-06-09T13:04:29Z

   Hi all,
   
   I am trying to improve the runtime of a big data warehouse application. One
   significant bottleneck found was insert performance, so I am investigating
   ways of getting Postgresql to insert data faster. I ran several tests on a
   fast machine to find out what performs best, and compared the results with
   the same actions in Oracle on that same machine.
   
   So far I am finding that PostgreSQL insert performance is several times
   slower than Oracle performance, and I would be grateful for some help
   trying to decrease this gap...
   
   To test I wrote a simple Java program which inserts data into a simple
   table, using statement batching and delayed commits. The table looks as
   follows:
   
   create table h_test(
   id_h integer
   , source_system_id integer
   , organisation_id integer
   , load_dts timestamp without time zone
   , boekingdetailid text
   );
   No constraints, no indexes.
   
   The java program and PostgreSQL run on the same machine. The best results
   I've got are:
   
   PostgreSQL inserts:
   
   Commit size 50.000 and batch size 10.000
   Inserted 1000000 rows in 7500 milliseconds, 142857.14285714287 rows per
   second
   Inserted 1000000 rows in 7410 milliseconds, 142857.14285714287 rows per
   second
   
   The exact same test done on Oracle (on the same machine) reports:
   
   Inserted 1000000 rows in 1072 milliseconds, 1000000.0 rows per second
   
   Increasing the row count in Oracle decreases this number a bit, but it's
   still fast:
   Inserted 24000000 rows in 47155 milliseconds, 510638.2978723404 rows per
   second (oracle)
   
   compared with:
   Inserted 24000000 rows in 159929 milliseconds, 150943.3962264151 rows per
   second (postgresql)
   
   I also created a small pg/sql stored procedure to insert the same 1 million
   rows, which runs in about 4 seconds, resulting in 250.000 rows a second.
   This is in the DB itself, but it still is twice as slow as Oracle with JDBC:
   CREATE or replace function test() returns void AS $$
   DECLARE
       count integer;
   BEGIN
       for count in 1..1000000 loop
           insert into
   h_test(id_h,source_system_id,organisation_id,load_dts,boekingdetailid)
               values(count, 1, 12, now(), 'boe' || count || 'king' || count);
       end loop;
   END;
   $$ LANGUAGE plpgsql;
   
   
   I already changed the following config parameters:
   work_mem 512MB
   synchronous_commit off
   shared_buffers 512mb
   commit_delay 100000
   autovacuum_naptime 10min
   
   Postgres version is 9.6.3 on Ubuntu 17.04 64 bit, on a i7-4790K with 16GB
   memory and an Intel 750 SSD. JDBC driver is postgresql-42.1.1.
   
   (btw: the actual load I'm trying to improve will load more than 132 million
   rows, and will grow).
   
   Any help is greatly appreciated!
   
   Regards,
   
   Frits
   

2. Re: Improving PostgreSQL insert performance

   Andreas Kretschmer <andreas@a-kretschmer.de> — 2017-06-09T13:24:15Z

   
   Am 09.06.2017 um 15:04 schrieb Frits Jalvingh:
   > Hi all,
   >
   > I am trying to improve the runtime of a big data warehouse 
   > application. One significant bottleneck found was insert performance, 
   > so I am investigating ways of getting Postgresql to insert data faster.
   
   * use COPY instead of Insert, it is much faster
   * bundle all Insert into one transaction
   * use a separate disk/spindel for the transaction log
   
   
   
   >
   > I already changed the following config parameters:
   > work_mem 512MB
   > synchronous_commit off
   > shared_buffers 512mb
   > commit_delay 100000
   > autovacuum_naptime 10min
   >
   > Postgres version is 9.6.3 on Ubuntu 17.04 64 bit, on a i7-4790K with 
   > 16GB memory and an Intel 750 SSD. JDBC driver is postgresql-42.1.1.
   >
   
   increase shared_buffers, with 16gb ram i would suggest 8gb
   
   
   Regards, Andreas
   -- 
   2ndQuadrant - The PostgreSQL Support Company.
   www.2ndQuadrant.com
   
   
   
   

3. Re: Improving PostgreSQL insert performance

   ktm@rice.edu <ktm@rice.edu> — 2017-06-09T13:28:57Z

   On Fri, Jun 09, 2017 at 03:24:15PM +0200, Andreas Kretschmer wrote:
   > 
   > 
   > Am 09.06.2017 um 15:04 schrieb Frits Jalvingh:
   > >Hi all,
   > >
   > >I am trying to improve the runtime of a big data warehouse
   > >application. One significant bottleneck found was insert
   > >performance, so I am investigating ways of getting Postgresql to
   > >insert data faster.
   > 
   > * use COPY instead of Insert, it is much faster
   > * bundle all Insert into one transaction
   > * use a separate disk/spindel for the transaction log
   > 
   > 
   > 
   > >
   > >I already changed the following config parameters:
   > >work_mem 512MB
   > >synchronous_commit off
   > >shared_buffers 512mb
   > >commit_delay 100000
   > >autovacuum_naptime 10min
   > >
   > >Postgres version is 9.6.3 on Ubuntu 17.04 64 bit, on a i7-4790K
   > >with 16GB memory and an Intel 750 SSD. JDBC driver is
   > >postgresql-42.1.1.
   > >
   > 
   > increase shared_buffers, with 16gb ram i would suggest 8gb
   
   +1 Without even checking, I think Oracle is configured to use a LOT
   more memory than 512mb.
   
   Regards,
   Ken
   
   
   

4. Re: Improving PostgreSQL insert performance

   Frits Jalvingh <jal@etc.to> — 2017-06-09T13:56:58Z

   Hi Kenneth, Andreas,
   
   Thanks for your tips!
   
   I increased shared_buffers to 8GB but it has no measurable effect at all. I
   think that is logical: shared buffers are important for querying but not
   for inserting; for that the speed to write to disk seems most important- no
   big reason to cache the data if the commit requires a full write anyway.
   I also changed the code to do only one commit; this also has no effect I
   can see.
   
   It is true that Oracle had more memory assigned to it (1.5G), but unlike
   Postgres (which is completely on a fast SSD) Oracle runs on slower disk
   (ZFS)..
   
   I will try copy, but I first need to investigate how to use it- its
   interface seems odd to say the least ;) I'll report back on that once done.
   
   Any other tips would be welcome!
   
   Regards,
   
   Frits
   
   On Fri, Jun 9, 2017 at 3:30 PM Kenneth Marshall <ktm@rice.edu> wrote:
   
   > On Fri, Jun 09, 2017 at 03:24:15PM +0200, Andreas Kretschmer wrote:
   > >
   > >
   > > Am 09.06.2017 um 15:04 schrieb Frits Jalvingh:
   > > >Hi all,
   > > >
   > > >I am trying to improve the runtime of a big data warehouse
   > > >application. One significant bottleneck found was insert
   > > >performance, so I am investigating ways of getting Postgresql to
   > > >insert data faster.
   > >
   > > * use COPY instead of Insert, it is much faster
   > > * bundle all Insert into one transaction
   > > * use a separate disk/spindel for the transaction log
   > >
   > >
   > >
   > > >
   > > >I already changed the following config parameters:
   > > >work_mem 512MB
   > > >synchronous_commit off
   > > >shared_buffers 512mb
   > > >commit_delay 100000
   > > >autovacuum_naptime 10min
   > > >
   > > >Postgres version is 9.6.3 on Ubuntu 17.04 64 bit, on a i7-4790K
   > > >with 16GB memory and an Intel 750 SSD. JDBC driver is
   > > >postgresql-42.1.1.
   > > >
   > >
   > > increase shared_buffers, with 16gb ram i would suggest 8gb
   >
   > +1 Without even checking, I think Oracle is configured to use a LOT
   > more memory than 512mb.
   >
   > Regards,
   > Ken
   >
   >
   > --
   > Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org)
   > To make changes to your subscription:
   > http://www.postgresql.org/mailpref/pgsql-performance
   >
   

5. Re: Improving PostgreSQL insert performance

   Scott Marlowe <scott.marlowe@gmail.com> — 2017-06-09T14:33:14Z

   On Fri, Jun 9, 2017 at 7:56 AM, Frits Jalvingh <jal@etc.to> wrote:
   > Hi Kenneth, Andreas,
   >
   > Thanks for your tips!
   >
   > I increased shared_buffers to 8GB but it has no measurable effect at all. I
   > think that is logical: shared buffers are important for querying but not for
   > inserting; for that the speed to write to disk seems most important- no big
   > reason to cache the data if the commit requires a full write anyway.
   > I also changed the code to do only one commit; this also has no effect I can
   > see.
   >
   > It is true that Oracle had more memory assigned to it (1.5G), but unlike
   > Postgres (which is completely on a fast SSD) Oracle runs on slower disk
   > (ZFS)..
   >
   > I will try copy, but I first need to investigate how to use it- its
   > interface seems odd to say the least ;) I'll report back on that once done.
   
   I you want an example of copy, just pg_dump a table:
   
   pg_dump -d smarlowe -t test
   
   (SNIP)
   COPY test (a, b) FROM stdin;
   1 abc
   2 xyz
   \.
   (SNIP)
   
   
   

6. Re: Improving PostgreSQL insert performance

   ktm@rice.edu <ktm@rice.edu> — 2017-06-09T14:36:37Z

   On Fri, Jun 09, 2017 at 01:56:58PM +0000, Frits Jalvingh wrote:
   > Hi Kenneth, Andreas,
   > 
   > Thanks for your tips!
   > 
   > I increased shared_buffers to 8GB but it has no measurable effect at all. I
   > think that is logical: shared buffers are important for querying but not
   > for inserting; for that the speed to write to disk seems most important- no
   > big reason to cache the data if the commit requires a full write anyway.
   > I also changed the code to do only one commit; this also has no effect I
   > can see.
   > 
   > It is true that Oracle had more memory assigned to it (1.5G), but unlike
   > Postgres (which is completely on a fast SSD) Oracle runs on slower disk
   > (ZFS)..
   > 
   > I will try copy, but I first need to investigate how to use it- its
   > interface seems odd to say the least ;) I'll report back on that once done.
   > 
   > Any other tips would be welcome!
   > 
   > Regards,
   > 
   > Frits
   
   Hi Frits,
   
   Here is an article that is still valid:
   
   https://www.depesz.com/2007/07/05/how-to-insert-data-to-database-as-fast-as-possible/
   
   Regards,
   Ken
   
   
   

7. Re: Improving PostgreSQL insert performance

   Frits Jalvingh <jal@etc.to> — 2017-06-09T14:39:37Z

   Hi all,
   
   Thanks a lot for the many responses!
   
   About preparing statements: this is done properly in Java, and pgsql does
   it by itself. So that cannot be done better ;)
   
   I tried the copy command, and that indeed works quite brilliantly:
   Inserted 24000000 rows in 22004 milliseconds, 1090710.7798582076 rows per
   second
   
   That's faster than Oracle. But with a very bad interface I have to say for
   normal database work.. I will try to make this work in the tooling, but it
   needs some very special code to format all possible values properly, and to
   manage the end of the copy, so it is not usable in general which is a pity,
   I think.
   
   So, I am still very interested in getting normal inserts faster, because
   that will gain speed for all work.. If Oracle can do it, and Postgres is
   able to insert fast with copy- where lies the bottleneck with the insert
   command? There seems to be quite a performance hit with the JDBC driver
   itself (as the stored procedure is a lot faster), so I can look into that.
   But even after that there is quite a gap..
   
   Regards,
   
   Frits
   
   On Fri, Jun 9, 2017 at 4:33 PM Scott Marlowe <scott.marlowe@gmail.com>
   wrote:
   
   > On Fri, Jun 9, 2017 at 7:56 AM, Frits Jalvingh <jal@etc.to> wrote:
   > > Hi Kenneth, Andreas,
   > >
   > > Thanks for your tips!
   > >
   > > I increased shared_buffers to 8GB but it has no measurable effect at
   > all. I
   > > think that is logical: shared buffers are important for querying but not
   > for
   > > inserting; for that the speed to write to disk seems most important- no
   > big
   > > reason to cache the data if the commit requires a full write anyway.
   > > I also changed the code to do only one commit; this also has no effect I
   > can
   > > see.
   > >
   > > It is true that Oracle had more memory assigned to it (1.5G), but unlike
   > > Postgres (which is completely on a fast SSD) Oracle runs on slower disk
   > > (ZFS)..
   > >
   > > I will try copy, but I first need to investigate how to use it- its
   > > interface seems odd to say the least ;) I'll report back on that once
   > done.
   >
   > I you want an example of copy, just pg_dump a table:
   >
   > pg_dump -d smarlowe -t test
   >
   > (SNIP)
   > COPY test (a, b) FROM stdin;
   > 1 abc
   > 2 xyz
   > \.
   > (SNIP)
   >
   

8. Re: Improving PostgreSQL insert performance

   Sunkara, Amrutha <amrutha@nytimes.com> — 2017-06-09T14:46:49Z

   Frits,
   
   When you use the copy command, are you doing anything special to get the
   run time that you are indicating?
   
   On Fri, Jun 9, 2017 at 10:39 AM, Frits Jalvingh <jal@etc.to> wrote:
   
   > Hi all,
   >
   > Thanks a lot for the many responses!
   >
   > About preparing statements: this is done properly in Java, and pgsql does
   > it by itself. So that cannot be done better ;)
   >
   > I tried the copy command, and that indeed works quite brilliantly:
   > Inserted 24000000 rows in 22004 milliseconds, 1090710.7798582076
   > <(779)%20858-2076> rows per second
   >
   > That's faster than Oracle. But with a very bad interface I have to say for
   > normal database work.. I will try to make this work in the tooling, but it
   > needs some very special code to format all possible values properly, and to
   > manage the end of the copy, so it is not usable in general which is a pity,
   > I think.
   >
   > So, I am still very interested in getting normal inserts faster, because
   > that will gain speed for all work.. If Oracle can do it, and Postgres is
   > able to insert fast with copy- where lies the bottleneck with the insert
   > command? There seems to be quite a performance hit with the JDBC driver
   > itself (as the stored procedure is a lot faster), so I can look into that.
   > But even after that there is quite a gap..
   >
   > Regards,
   >
   > Frits
   >
   > On Fri, Jun 9, 2017 at 4:33 PM Scott Marlowe <scott.marlowe@gmail.com>
   > wrote:
   >
   >> On Fri, Jun 9, 2017 at 7:56 AM, Frits Jalvingh <jal@etc.to> wrote:
   >> > Hi Kenneth, Andreas,
   >> >
   >> > Thanks for your tips!
   >> >
   >> > I increased shared_buffers to 8GB but it has no measurable effect at
   >> all. I
   >> > think that is logical: shared buffers are important for querying but
   >> not for
   >> > inserting; for that the speed to write to disk seems most important- no
   >> big
   >> > reason to cache the data if the commit requires a full write anyway.
   >> > I also changed the code to do only one commit; this also has no effect
   >> I can
   >> > see.
   >> >
   >> > It is true that Oracle had more memory assigned to it (1.5G), but unlike
   >> > Postgres (which is completely on a fast SSD) Oracle runs on slower disk
   >> > (ZFS)..
   >> >
   >> > I will try copy, but I first need to investigate how to use it- its
   >> > interface seems odd to say the least ;) I'll report back on that once
   >> done.
   >>
   >> I you want an example of copy, just pg_dump a table:
   >>
   >> pg_dump -d smarlowe -t test
   >>
   >> (SNIP)
   >> COPY test (a, b) FROM stdin;
   >> 1 abc
   >> 2 xyz
   >> \.
   >> (SNIP)
   >>
   >
   

9. Re: Improving PostgreSQL insert performance

   ktm@rice.edu <ktm@rice.edu> — 2017-06-09T14:53:47Z

   On Fri, Jun 09, 2017 at 02:39:37PM +0000, Frits Jalvingh wrote:
   > Hi all,
   > 
   > Thanks a lot for the many responses!
   > 
   > About preparing statements: this is done properly in Java, and pgsql does
   > it by itself. So that cannot be done better ;)
   > 
   > I tried the copy command, and that indeed works quite brilliantly:
   > Inserted 24000000 rows in 22004 milliseconds, 1090710.7798582076 rows per
   > second
   > 
   > That's faster than Oracle. But with a very bad interface I have to say for
   > normal database work.. I will try to make this work in the tooling, but it
   > needs some very special code to format all possible values properly, and to
   > manage the end of the copy, so it is not usable in general which is a pity,
   > I think.
   > 
   > So, I am still very interested in getting normal inserts faster, because
   > that will gain speed for all work.. If Oracle can do it, and Postgres is
   > able to insert fast with copy- where lies the bottleneck with the insert
   > command? There seems to be quite a performance hit with the JDBC driver
   > itself (as the stored procedure is a lot faster), so I can look into that.
   > But even after that there is quite a gap..
   > 
   > Regards,
   > 
   > Frits
   
   Hi Frits,
   
   Have you looked at UNLOGGED tables and also having more that 1 insert
   stream running at a time. Sometimes multiple parallel inserts can be
   faster.
   
   Regards,
   Ken
   
   
   

10. Re: Improving PostgreSQL insert performance

    Frits Jalvingh <jal@etc.to> — 2017-06-09T14:55:04Z

    I am not doing anything special I guess. I am adding the results of the
    tests and the programs I'm using to the following page:
    
    https://etc.to/confluence/display/~admjal/PostgreSQL+performance+tests
    
    The copy example, in Java, is at the end. All of the examples use trivial
    data and the same data. If you find fault please let me know ;) But the
    copy does insert the records as they can be seen ;)
    
    On Fri, Jun 9, 2017 at 4:47 PM Sunkara, Amrutha <amrutha@nytimes.com> wrote:
    
    > Frits,
    >
    > When you use the copy command, are you doing anything special to get the
    > run time that you are indicating?
    >
    

11. Re: Improving PostgreSQL insert performance

    Frits Jalvingh <jal@etc.to> — 2017-06-09T14:57:58Z

    Hi Kenneth,
    
    I tried unlogged before, but as long as the commit interval is long it had
    no discerning effect that I could see.
    

12. Re: Improving PostgreSQL insert performance

    Frits Jalvingh <jal@etc.to> — 2017-06-09T15:05:13Z

    Hi Babu,
    
    No, I did not, and the effect is quite great:
    
    Inserted 1000000 rows in 2535 milliseconds, 394477.3175542406 rows per
    second
    Inserted 1000000 rows in 2553 milliseconds, 391696.0438699569 rows per
    second
    
    compared to (without your parameter):
    Inserted 1000000 rows in 7643 milliseconds, 130838.67591259976 rows per
    second
    
    That is quite an increase!! Thanks a lot for the tip!!
    
    For those keeping score: we're now at 77% of Oracle's performance- without
    copy ;)
    
    
    
    
    >
    

13. Re: Improving PostgreSQL insert performance

    John Gorman <jgorman@eldocomp.com> — 2017-06-09T15:08:45Z

    You need to be careful with the setFetchSize we have tables with over 10 million rows and many columns and the PostgreSQL JDBC driver silently fails, ignores the fetch size and tries to read the entire table content into memory. I spent many agonizing days on this.
    
    ps.setFetchSize(65536);
    
    Regards
    John
    
    
    From: pgsql-performance-owner@postgresql.org [mailto:pgsql-performance-owner@postgresql.org] On Behalf Of Frits Jalvingh
    Sent: Friday, June 09, 2017 7:55 AM
    To: Sunkara, Amrutha; pgsql-performance@postgresql.org
    Subject: Re: [PERFORM] Improving PostgreSQL insert performance
    
    I am not doing anything special I guess. I am adding the results of the tests and the programs I'm using to the following page:
    
    https://etc.to/confluence/display/~admjal/PostgreSQL+performance+tests
    
    The copy example, in Java, is at the end. All of the examples use trivial data and the same data. If you find fault please let me know ;) But the copy does insert the records as they can be seen ;)
    On Fri, Jun 9, 2017 at 4:47 PM Sunkara, Amrutha <amrutha@nytimes.com<mailto:amrutha@nytimes.com>> wrote:
    Frits,
    
    When you use the copy command, are you doing anything special to get the run time that you are indicating?
    

14. Re: Improving PostgreSQL insert performance

    Frits Jalvingh <jal@etc.to> — 2017-06-09T15:12:33Z

    Hi John,
    
    Yes, I was aware and amazed by that ;) It is actually the fetch size in
    combination with autocommit being on; that dies the sweet OOM death as soon
    as the table gets big.
    
    But Postgres read performance, with autocommit off and fetch size arond
    64K, is quite OK. But it's good to get this mentioned a lot, because as you
    said you can spend quite some time wondering about this!
    
    On Fri, Jun 9, 2017 at 5:08 PM John Gorman <jgorman@eldocomp.com> wrote:
    
    > You need to be careful with the setFetchSize we have tables with over 10
    > million rows and many columns and the PostgreSQL JDBC driver silently
    > fails, ignores the fetch size and tries to read the entire table content
    > into memory. I spent many agonizing days on this.
    >
    >
    >
    > ps.setFetchSize(65536);
    >
    >
    >
    > Regards
    >
    > John
    >
    >
    >
    >
    >
    > *From:* pgsql-performance-owner@postgresql.org [mailto:
    > pgsql-performance-owner@postgresql.org] *On Behalf Of *Frits Jalvingh
    > *Sent:* Friday, June 09, 2017 7:55 AM
    > *To:* Sunkara, Amrutha; pgsql-performance@postgresql.org
    >
    >
    > *Subject:* Re: [PERFORM] Improving PostgreSQL insert performance
    >
    >
    >
    > I am not doing anything special I guess. I am adding the results of the
    > tests and the programs I'm using to the following page:
    >
    >
    >
    > https://etc.to/confluence/display/~admjal/PostgreSQL+performance+tests
    >
    >
    >
    > The copy example, in Java, is at the end. All of the examples use trivial
    > data and the same data. If you find fault please let me know ;) But the
    > copy does insert the records as they can be seen ;)
    >
    > On Fri, Jun 9, 2017 at 4:47 PM Sunkara, Amrutha <amrutha@nytimes.com>
    > wrote:
    >
    > Frits,
    >
    >
    >
    > When you use the copy command, are you doing anything special to get the
    > run time that you are indicating?
    >
    >
    

15. Re: Improving PostgreSQL insert performance

    Scott Marlowe <scott.marlowe@gmail.com> — 2017-06-09T15:16:51Z

    On Fri, Jun 9, 2017 at 9:12 AM, Frits Jalvingh <jal@etc.to> wrote:
    > Hi John,
    >
    > Yes, I was aware and amazed by that ;) It is actually the fetch size in
    > combination with autocommit being on; that dies the sweet OOM death as soon
    > as the table gets big.
    >
    > But Postgres read performance, with autocommit off and fetch size arond 64K,
    > is quite OK. But it's good to get this mentioned a lot, because as you said
    > you can spend quite some time wondering about this!
    
    No production db server should have the oom killer enabled.
    
    
    

16. Re: Improving PostgreSQL insert performance

    Frits Jalvingh <jal@etc.to> — 2017-06-09T15:22:35Z

    Hi Babu,
    
    That was all already done, as it is common practice for JDBC. Your
    parameter was added to the code that already did all that - and worked
    brilliantly there ;)
    
    
    >
    

17. Re: Improving PostgreSQL insert performance

    ktm@rice.edu <ktm@rice.edu> — 2017-06-09T15:33:33Z

    On Fri, Jun 09, 2017 at 03:22:35PM +0000, Frits Jalvingh wrote:
    > Hi Babu,
    > 
    > That was all already done, as it is common practice for JDBC. Your
    > parameter was added to the code that already did all that - and worked
    > brilliantly there ;)
    > 
    Hi Frits,
    
    What was the parameter? I did not see an Email in the thread from Babu.
    
    Regards,
    Ken
    
    
    

18. Re: Improving PostgreSQL insert performance

    Frits Jalvingh <jal@etc.to> — 2017-06-09T15:37:10Z

    The parameter was
    reWriteBatchedInserts = true
    
    Either added in connection properties of in the connection URL like
    
    jdbc:postgresql://localhost:5432/datavault_12_tst?reWriteBatchedInserts=true
    
    BTW: It seems you need a recent driver for this; I'm
    using postgresql-42.1.1.jar
    
    On Fri, Jun 9, 2017 at 5:33 PM Kenneth Marshall <ktm@rice.edu> wrote:
    
    > On Fri, Jun 09, 2017 at 03:22:35PM +0000, Frits Jalvingh wrote:
    > > Hi Babu,
    > >
    > > That was all already done, as it is common practice for JDBC. Your
    > > parameter was added to the code that already did all that - and worked
    > > brilliantly there ;)
    > >
    > Hi Frits,
    >
    > What was the parameter? I did not see an Email in the thread from Babu.
    >
    > Regards,
    > Ken
    >
    

19. Re: Improving PostgreSQL insert performance

    Jeff Janes <jeff.janes@gmail.com> — 2017-06-09T17:07:07Z

    On Fri, Jun 9, 2017 at 6:04 AM, Frits Jalvingh <jal@etc.to> wrote:
    
    >
    > I already changed the following config parameters:
    > work_mem 512MB
    > synchronous_commit off
    >
    
    Since you are already batching up commits into large chunks, this setting
    is not very useful, but does risk you losing supposedly-committed data upon
    a crash.  I would not do it.
    
    
    > shared_buffers 512mb
    >
    
    You might try increasing wal_buffers, but the default for this size of
    shared_buffers is 16MB, which is usually big enough.
    
    One thing you are missing is max_wal_size.  The default value of that is
    probably too small for what you are doing.
    
    But if you are not using COPY, then maybe none of this matters as the
    bottleneck will be elsewhere.
    
    Cheers,
    
    Jeff
    

20. Re: Improving PostgreSQL insert performance

    Vladimir Sitnikov <sitnikov.vladimir@gmail.com> — 2017-06-09T22:08:34Z

    Frits,
    
    Would you mind sharing the source code of your benchmark?
    
    >BTW: It seems you need a recent driver for this; I'm
    using postgresql-42.1.1.jar
    
    Technically speaking, reWriteBatchedInserts was introduced in 9.4.1209
    (2016-07-15)
    
    Vladimir
    

21. Re: Improving PostgreSQL insert performance

    Frits Jalvingh <jal@etc.to> — 2017-06-10T11:12:43Z

    On Sat, Jun 10, 2017 at 12:08 AM Vladimir Sitnikov <
    sitnikov.vladimir@gmail.com> wrote:
    
    > Would you mind sharing the source code of your benchmark?
    >
    
    The source code for the several tests, plus the numbers collected so far,
    can be found at:
    
    https://etc.to/confluence/display/~admjal/PostgreSQL+performance+tests
    
    Regards,
    
    Frits
    

22. Re: Improving PostgreSQL insert performance

    Nicolas Paris <niparisco@gmail.com> — 2017-06-10T20:12:35Z

    > I tried the copy command, and that indeed works quite brilliantly:
    > Inserted 24000000 rows in 22004 milliseconds, 1090710.7798582076 rows per
    > second
    > 
    > That's faster than Oracle. But with a very bad interface I have to say for
    > normal database work.. I will try to make this work in the tooling, but it
    > needs some very special code to format all possible values properly, and to
    > manage the end of the copy, so it is not usable in general which is a pity, I
    > think.
    
    Have you thought about the COPY with binary format ? Thats looks more
    robust than the text format you used in your benchmarks.
    
    
    

23. Re: Improving PostgreSQL insert performance

    Frits Jalvingh <jal@etc.to> — 2017-06-10T20:37:48Z

    I think binary is worse.. according to the postgres documentation:
    
    The binary format option causes all data to be stored/read as binary format
    rather than as text. It is somewhat faster than the text and CSV formats,
    but a binary-format file is less portable across machine architectures and
    PostgreSQL versions. Also, the binary format is very data type specific;
    for example it will not work to output binary data from a smallint column
    and read it into an integer column, even though that would work fine in
    text format.
    
    By itself it is similar in badness as both require completely different
    semantics than insert..
    On Sat, 10 Jun 2017 at 22:12, Nicolas Paris <niparisco@gmail.com> wrote:
    
    > > I tried the copy command, and that indeed works quite brilliantly:
    > > Inserted 24000000 rows in 22004 milliseconds, 1090710.7798582076 rows per
    > > second
    > >
    > > That's faster than Oracle. But with a very bad interface I have to say
    > for
    > > normal database work.. I will try to make this work in the tooling, but
    > it
    > > needs some very special code to format all possible values properly, and
    > to
    > > manage the end of the copy, so it is not usable in general which is a
    > pity, I
    > > think.
    >
    > Have you thought about the COPY with binary format ? Thats looks more
    > robust than the text format you used in your benchmarks.
    >
    

24. Re: Improving PostgreSQL insert performance

    Alvaro Herrera <alvherre@2ndquadrant.com> — 2017-06-11T02:32:14Z

    Frits Jalvingh wrote:
    
    > So, I am still very interested in getting normal inserts faster, because
    > that will gain speed for all work.. If Oracle can do it, and Postgres is
    > able to insert fast with copy- where lies the bottleneck with the insert
    > command? There seems to be quite a performance hit with the JDBC driver
    > itself (as the stored procedure is a lot faster), so I can look into that.
    > But even after that there is quite a gap..
    
    Did you try inserting multiple tuples in one command?  Something like
    INSERT INTO .. VALUES ('col1', 'col2'), ('col1', 'col2'), ('col1', 'col2')
    It's supposed to be faster than single-row inserts, though I don't
    know by how much.
    
    -- 
    Álvaro Herrera                https://www.2ndQuadrant.com/
    PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
    
    
    

25. Re: Improving PostgreSQL insert performance

    Joe Conway <mail@joeconway.com> — 2017-06-11T04:15:18Z

    On 06/10/2017 07:32 PM, Alvaro Herrera wrote:
    > Frits Jalvingh wrote:
    > 
    >> So, I am still very interested in getting normal inserts faster, because
    >> that will gain speed for all work.. If Oracle can do it, and Postgres is
    >> able to insert fast with copy- where lies the bottleneck with the insert
    >> command? There seems to be quite a performance hit with the JDBC driver
    >> itself (as the stored procedure is a lot faster), so I can look into that.
    >> But even after that there is quite a gap..
    > 
    > Did you try inserting multiple tuples in one command?  Something like
    > INSERT INTO .. VALUES ('col1', 'col2'), ('col1', 'col2'), ('col1', 'col2')
    > It's supposed to be faster than single-row inserts, though I don't
    > know by how much.
    
    When I did the testing of the patch originally I saw significant
    improvements, e.g. 8x in early versions. The thread is here:
    https://www.postgresql.org/message-id/flat/44C4451A.4010906%40joeconway.com#44C4451A.4010906@joeconway.com
    
    Joe
    
    -- 
    Crunchy Data - http://crunchydata.com
    PostgreSQL Support for Secure Enterprises
    Consulting, Training, & Open Source Development
    
    

26. Re: Improving PostgreSQL insert performance

    Frits Jalvingh <jal@etc.to> — 2017-06-11T08:44:04Z

    Hi Alvaro,
    
    I did not try that, to be honest. I am using a single prepared statement so
    that the database needs to parse it only once. All executes then use the
    batched parameters.
    I will try this later on, but I wonder whether having to reparse the
    statement every time compared to one prepared statement would actually be
    faster.
    
    But thanks for the tip; I will take a look.
    
    Regards,
    
    Frits
    

27. Re: Improving PostgreSQL insert performance

    Vladimir Sitnikov <sitnikov.vladimir@gmail.com> — 2017-06-11T09:30:29Z

    Alvaro>Something like
    INSERT INTO .. VALUES ('col1', 'col2'), ('col1', 'col2'), ('col1', 'col2')>I
    did not
    Frits>try that, to be honest.
    
    pgjdbc does automatically rewrite insert values(); into insert ...
    values(),(),(),() when reWriteBatchedInserts=true. I don't expect manual
    multivalues to be noticeably faster there.
    
    
    Frits>https://etc.to/confluence/display/~admjal/PostgreSQL+performance+tests
    
    Do you really intend to measure just a single insert operation?
    It looks odd, as typical applications would execute inserts for quite a
    while before they terminate.
    
    You are including lots of warmup overheads (e.g. JIT-compilation), so your
    approach does not measure peak performance.
    On the other hand, you are not measuring enough time to catch things like
    "DB log switch".
    
    Would you please use JMH as a load driver?
    Here's an example:
    https://github.com/pgjdbc/pgjdbc/blob/master/ubenchmark/src/main/java/org/postgresql/benchmark/statement/InsertBatch.java
    
    
    Vladimir
    
    >
    

28. Re: Improving PostgreSQL insert performance

    Alvaro Herrera <alvherre@2ndquadrant.com> — 2017-06-11T12:36:48Z

    Vladimir Sitnikov wrote:
    > Alvaro>Something like
    > INSERT INTO .. VALUES ('col1', 'col2'), ('col1', 'col2'), ('col1', 'col2')>I
    > did not
    > Frits>try that, to be honest.
    > 
    > pgjdbc does automatically rewrite insert values(); into insert ...
    > values(),(),(),() when reWriteBatchedInserts=true. I don't expect manual
    > multivalues to be noticeably faster there.
    
    Ahh, so that's what that option does :-)  Nice to know -- great feature.
    
    -- 
    Álvaro Herrera                https://www.2ndQuadrant.com/
    PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
    
    
    

29. Re: Improving PostgreSQL insert performance

    Русинов Семен <mrpinkolik@gmail.com> — 2026-05-04T18:03:41Z

    Hello Frits,
    
    Would you mind sharing an updated link to your benchmark and source code?
    
    
    I am also currently tuning postgresql single insert performance for the 
    outbox pattern. And I'm stuck at 35k inserts per second. However, it 
    doesn't look like I have reached hardware limit. CPU usage is moderate, 
    around 20%, RAM is also 20% free. I've tried all sorts of optimizations 
    but still can't get pass through this RPS, and neither can I understand 
    what is limiting postgres from inserting at a faster pace.
    
    Best regards,
    Simon
    
    On 6/10/17 16:12, Frits Jalvingh wrote:
    >
    > On Sat, Jun 10, 2017 at 12:08 AM Vladimir Sitnikov 
    > <sitnikov.vladimir@gmail.com> wrote:
    >
    >     Would you mind sharing the source code of your benchmark?
    >
    >
    > The source code for the several tests, plus the numbers collected so 
    > far, can be found at:
    >
    > https://etc.to/confluence/display/~admjal/PostgreSQL+performance+tests
    >
    > Regards,
    >
    > Frits