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  1. Rearm statement_timeout after each executed query.

  1. Statement timeout behavior in extended queries

    Tatsuo Ishii <ishii@sraoss.co.jp> — 2017-02-22T02:50:44Z

    Last year I have proposed an enhancement regarding behavior of the
    statement timeout in extended queries.
    
    https://www.postgresql.org/message-id/20160528.220442.1489791680347556026.t-ishii%40sraoss.co.jp
    
    IMO the current behavior is counter intuitive and I would like to
    change it toward PostgreSQL 10.0.
    
    For example, suppose that the timeout is set to 4 seconds and the
    first query takes 2 seconds and the second query takes 3 seconds. Then
    the statement timeout is triggered if a sync message is sent to
    backend after the second query.
    
    Moreover, log_duration or log_min_duration_statement shows that each
    query took 2 or 3 seconds of course, which is not very consistent with
    the statement timeout IMO.
    
    Attached patch tries to change the behavior, by checking statement
    timeout against each phase of an extended query.
    
    To test the patch, I have created a small tool called "pgproto", which
    can issue arbitrary sequence of frontend/backend message, reading from a
    text file.
    
    https://github.com/tatsuo-ishii/pgproto
    (to build the program, you need C compiler and libpq)
    
    A test data is here:
    ----------------------------------------------------------
    #
    # Test case for statement timeout patch.
    #
    'Q'	"SET statement_timeout = '4s'"
    
    # Receive response from backend
    'Y'
    
    # Execute statement which takes 3 seconds.
    'P'	"S1"	"SELECT pg_sleep(3)"	0
    'B'	""	"S1"	0	0	0
    'E'	""	0
    'C'	'S'	"S1"
    
    # Execute statement which takes 2 seconds.
    'P'	"S2"	"SELECT pg_sleep(2)"	0
    'B'	""	"S2"	0	0	0
    'E'	""	0
    'C'	'S'	"S2"
    
    # Issue Sync message
    'S'
    
    # Receive response from backend
    'Y'
    
    # Send terminate message
    'X'
    ----------------------------------------------------------
    
    In each row, the first column corresponds to the message type defined
    in frontend/backend protocol (except 'Y', which asks pgproto to
    collect responses from backend). Each column is separated with a tab
    character.
    
    To run the test:
    
    pgproto -f data_file -p port_number -d database_name
    
    With the attached patch, "SELECT pg_sleep(3)" and "SELECT pg_sleep(2)"
    does not trigger the statement timeout as expected, while existing
    code triggers the statement timeout after the sync message is sent.
    
    Best regards,
    --
    Tatsuo Ishii
    SRA OSS, Inc. Japan
    English: http://www.sraoss.co.jp/index_en.php
    Japanese:http://www.sraoss.co.jp
    
  2. Re: Statement timeout behavior in extended queries

    David Fetter <david@fetter.org> — 2017-02-26T21:47:16Z

    On Wed, Feb 22, 2017 at 11:50:44AM +0900, Tatsuo Ishii wrote:
    > Last year I have proposed an enhancement regarding behavior of the
    > statement timeout in extended queries.
    > 
    > https://www.postgresql.org/message-id/20160528.220442.1489791680347556026.t-ishii%40sraoss.co.jp
    > 
    > IMO the current behavior is counter intuitive and I would like to
    > change it toward PostgreSQL 10.0.
    > 
    > For example, suppose that the timeout is set to 4 seconds and the
    > first query takes 2 seconds and the second query takes 3 seconds. Then
    > the statement timeout is triggered if a sync message is sent to
    > backend after the second query.
    > 
    > Moreover, log_duration or log_min_duration_statement shows that each
    > query took 2 or 3 seconds of course, which is not very consistent with
    > the statement timeout IMO.
    > 
    > Attached patch tries to change the behavior, by checking statement
    > timeout against each phase of an extended query.
    > 
    > To test the patch, I have created a small tool called "pgproto", which
    > can issue arbitrary sequence of frontend/backend message, reading from a
    > text file.
    > 
    > https://github.com/tatsuo-ishii/pgproto
    > (to build the program, you need C compiler and libpq)
    
    Does it seem reasonable to start making this into a regression test
    and/or fuzz test for the protocol itself?
    
    Best,
    David.
    -- 
    David Fetter <david(at)fetter(dot)org> http://fetter.org/
    Phone: +1 415 235 3778  AIM: dfetter666  Yahoo!: dfetter
    Skype: davidfetter      XMPP: david(dot)fetter(at)gmail(dot)com
    
    Remember to vote!
    Consider donating to Postgres: http://www.postgresql.org/about/donate
    
    
    
  3. Re: Statement timeout behavior in extended queries

    Tatsuo Ishii <ishii@sraoss.co.jp> — 2017-02-27T00:14:34Z

    > On Wed, Feb 22, 2017 at 11:50:44AM +0900, Tatsuo Ishii wrote:
    >> Last year I have proposed an enhancement regarding behavior of the
    >> statement timeout in extended queries.
    >> 
    >> https://www.postgresql.org/message-id/20160528.220442.1489791680347556026.t-ishii%40sraoss.co.jp
    >> 
    >> IMO the current behavior is counter intuitive and I would like to
    >> change it toward PostgreSQL 10.0.
    >> 
    >> For example, suppose that the timeout is set to 4 seconds and the
    >> first query takes 2 seconds and the second query takes 3 seconds. Then
    >> the statement timeout is triggered if a sync message is sent to
    >> backend after the second query.
    >> 
    >> Moreover, log_duration or log_min_duration_statement shows that each
    >> query took 2 or 3 seconds of course, which is not very consistent with
    >> the statement timeout IMO.
    >> 
    >> Attached patch tries to change the behavior, by checking statement
    >> timeout against each phase of an extended query.
    >> 
    >> To test the patch, I have created a small tool called "pgproto", which
    >> can issue arbitrary sequence of frontend/backend message, reading from a
    >> text file.
    >> 
    >> https://github.com/tatsuo-ishii/pgproto
    >> (to build the program, you need C compiler and libpq)
    > 
    > Does it seem reasonable to start making this into a regression test
    > and/or fuzz test for the protocol itself?
    
    I personally think the regression tests ought to include tests for
    extended query protocols and pgproto could be an useful tool to
    implement that. Of course if we are going for that direction, pgproto
    needs to be a contrib module first.
    
    Best regards,
    --
    Tatsuo Ishii
    SRA OSS, Inc. Japan
    English: http://www.sraoss.co.jp/index_en.php
    Japanese:http://www.sraoss.co.jp
    
    
    
  4. Re: Statement timeout behavior in extended queries

    Tsunakawa, Takayuki <tsunakawa.takay@jp.fujitsu.com> — 2017-04-03T07:00:13Z

    Hello,
    
    
    I've reviewed the patch.  My understanding is as follows.  Please correct me if I'm wrong.
    
    * The difference is that the Execute message stops the statement_timeout timer, so that the execution of one statement doesn't shorten the timeout period of subsequent statements when they are run in batch followed by a single Sync message.
    
    * This patch is also necessary (or desirable) for the feature "Pipelining/batch mode support for libpq," which is being developed for PG 10.  This patch enables correct timeout handling for each statement execution in a batch.  Without this patch, the entire batch of statements is subject to statement_timeout.  That's different from what the manual describes about statement_timeout.  statement_timeout should measure execution of each statement.
    
    
    Below are what I found in the patch.
    
    
    (1)
    +static bool st_timeout = false;
    
    I think the variable name would better be stmt_timeout_enabled or stmt_timer_started, because other existing names use stmt to abbreviate statement, and thhis variable represents a state (see xact_started for example.)
    
    
    (2)
    +static void enable_statement_timeout(void)
    +{
    
    +static void disable_statement_timeout(void)
    +{
    
    "static void" and the remaining line should be on different lines, as other functions do.
    
    
    
    (3)
    +			/*
    +			 * Sanity check
    +			 */
    +			if (!xact_started)
    +			{
    +				ereport(ERROR,
    +						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
    +						 errmsg("Transaction must have been already started to set statement timeout")));
    +			}
    
    I think this fragment can be deleted, because enable/disable_timeout() is used only at limited places in postgres.c, so I don't see the chance of misuse.
    
    
    Regards
    Takayuki Tsunakawa
    
    
    
    
  5. Re: Statement timeout behavior in extended queries

    Tatsuo Ishii <ishii@sraoss.co.jp> — 2017-04-03T08:24:09Z

    Thank you for reviewing my patch!
    
    > Hello,
    > 
    > 
    > I've reviewed the patch.  My understanding is as follows.  Please correct me if I'm wrong.
    > 
    > * The difference is that the Execute message stops the statement_timeout timer, 
    
    No. Parse, bind and Execute message indivually stops and starts the
    statement_timeout timer with the patch. Unless there's a lock
    conflict, parse and bind will take very short time. So actually users
    could only observe the timeout in execute message though.
    
    > so that the execution of one statement doesn't shorten the timeout
    > period of subsequent statements when they are run in batch followed by
    > a single Sync message.
    
    This is true. Currently multiple set of parse/bind/execute will not
    trigger statement timeout until sync message is sent to
    backend. Suppose statement_timeout is set to 3 seconds, combo A
    (parse/bind/execute) takes 2 seconds and combo B (parse/bind/execute)
    takes 2 seconds then a sync message is followed. Currently statement
    timeout is fired in the run of combo B (assuming that parse and bind
    take almost 0 seconds). With my patch, no statement timeout will be
    fired because both combo A and combo B runs within 3 seconds.
    
    > * This patch is also necessary (or desirable) for the feature "Pipelining/batch mode support for libpq," which is being developed for PG 10.  This patch enables correct timeout handling for each statement execution in a batch.  Without this patch, the entire batch of statements is subject to statement_timeout.  That's different from what the manual describes about statement_timeout.  statement_timeout should measure execution of each statement.
    
    True.
    
    > Below are what I found in the patch.
    > 
    > 
    > (1)
    > +static bool st_timeout = false;
    > 
    > I think the variable name would better be stmt_timeout_enabled or stmt_timer_started, because other existing names use stmt to abbreviate statement, and thhis variable represents a state (see xact_started for example.)
    
    Agreed. Chaged to stmt_timer_started.
    
    > (2)
    > +static void enable_statement_timeout(void)
    > +{
    > 
    > +static void disable_statement_timeout(void)
    > +{
    > 
    > "static void" and the remaining line should be on different lines, as other functions do.
    
    Fixed.
    
    > (3)
    > +			/*
    > +			 * Sanity check
    > +			 */
    > +			if (!xact_started)
    > +			{
    > +				ereport(ERROR,
    > +						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
    > +						 errmsg("Transaction must have been already started to set statement timeout")));
    > +			}
    > 
    > I think this fragment can be deleted, because enable/disable_timeout() is used only at limited places in postgres.c, so I don't see the chance of misuse.
    
    I'd suggest leave it as it is. Because it might be possible that the
    function is used in different place in the future. Or at least we
    should document the pre-condition as a comment.
    
    revised patch attached.
    --
    Tatsuo Ishii
    SRA OSS, Inc. Japan
    English: http://www.sraoss.co.jp/index_en.php
    Japanese:http://www.sraoss.co.jp
    
  6. Re: Statement timeout behavior in extended queries

    Tom Lane <tgl@sss.pgh.pa.us> — 2017-04-03T14:05:16Z

    Tatsuo Ishii <ishii@sraoss.co.jp> writes:
    >> * The difference is that the Execute message stops the statement_timeout timer, 
    
    > No. Parse, bind and Execute message indivually stops and starts the
    > statement_timeout timer with the patch.
    
    That seems like it could represent quite a lot of added overhead,
    on machines where gettimeofday() is slow ... which is still a lot
    of them, unfortunately.
    
    			regards, tom lane
    
    
    
  7. Re: Statement timeout behavior in extended queries

    Tatsuo Ishii <ishii@sraoss.co.jp> — 2017-04-03T14:31:59Z

    > That seems like it could represent quite a lot of added overhead,
    > on machines where gettimeofday() is slow ... which is still a lot
    > of them, unfortunately.
    
    Maybe. I think we could eliminate restarting the timer for parse and
    bind.
    
    Best regards,
    --
    Tatsuo Ishii
    SRA OSS, Inc. Japan
    English: http://www.sraoss.co.jp/index_en.php
    Japanese:http://www.sraoss.co.jp
    
    
    
  8. Re: Statement timeout behavior in extended queries

    Andres Freund <andres@anarazel.de> — 2017-04-03T18:25:49Z

    On 2017-04-03 23:31:59 +0900, Tatsuo Ishii wrote:
    > > That seems like it could represent quite a lot of added overhead,
    > > on machines where gettimeofday() is slow ... which is still a lot
    > > of them, unfortunately.
    > 
    > Maybe. I think we could eliminate restarting the timer for parse and
    > bind.
    
    I've moved this patch to the next CF - it's been submitted fairly late
    in the v10 cycle and there's obviously design work ongoing.
    
    - Andres
    
    
    
  9. Re: Statement timeout behavior in extended queries

    Tsunakawa, Takayuki <tsunakawa.takay@jp.fujitsu.com> — 2017-04-04T03:02:08Z

    From: pgsql-hackers-owner@postgresql.org
    > [mailto:pgsql-hackers-owner@postgresql.org] On Behalf Of Tatsuo Ishii
    > No. Parse, bind and Execute message indivually stops and starts the
    > statement_timeout timer with the patch. Unless there's a lock conflict,
    > parse and bind will take very short time. So actually users could only
    > observe the timeout in execute message though.
    
    Where is the statement_timeout timer stopped when processing Parse and Bind messages?  Do you mean the following sequence of operations are performed in this patch?
    
    Parse(statement1)
      start timer
      stop timer
    Bind(statement1, portal1)
      start timer
      stop timer
    Execute(portal1)
      start timer
      stop timer
    Sync
    
    It looks like the patch does the following.  I think this is desirable, because starting and stopping the timer for each message may be costly as Tom said.
    
    Parse(statement1)
      start timer
    Bind(statement1, portal1)
    Execute(portal1)
      stop timer
    Sync
    
    
    > > (3)
    > > +			/*
    > > +			 * Sanity check
    > > +			 */
    > > +			if (!xact_started)
    > > +			{
    > > +				ereport(ERROR,
    > > +
    > 	(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
    > > +						 errmsg("Transaction
    > must have been already started to set statement timeout")));
    > > +			}
    > >
    > > I think this fragment can be deleted, because enable/disable_timeout()
    > is used only at limited places in postgres.c, so I don't see the chance
    > of misuse.
    > 
    > I'd suggest leave it as it is. Because it might be possible that the function
    > is used in different place in the future. Or at least we should document
    > the pre-condition as a comment.
    
    OK, I favor documenting to reduce code, but I don't have a strong opinion.  I'd like to leave this to the committer.  One thing to note is that you can remove { and } in the following code like other places.
    
    +			if (!xact_started)
    +			{
    +				ereport(ERROR,
    +						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
    +						 errmsg("Transaction must have been already started to set statement timeout")));
    +			}
    
    Regards
    Takayuki Tsunakawa
    
    
    
    
  10. Re: Statement timeout behavior in extended queries

    Tatsuo Ishii <ishii@sraoss.co.jp> — 2017-04-04T03:26:58Z

    > Where is the statement_timeout timer stopped when processing Parse and Bind messages?
    
    Actually the statement timer is replaced with new statement timer
    value in enable_statement_timeout().
    
    > Do you mean the following sequence of operations are performed in this patch?
    > 
    > Parse(statement1)
    >   start timer
    >   stop timer
    > Bind(statement1, portal1)
    >   start timer
    >   stop timer
    > Execute(portal1)
    >   start timer
    >   stop timer
    > Sync
    
    Yes.
    
    > It looks like the patch does the following.  I think this is desirable, because starting and stopping the timer for each message may be costly as Tom said.
    > Parse(statement1)
    >   start timer
    > Bind(statement1, portal1)
    > Execute(portal1)
    >   stop timer
    > Sync
    
    This doesn't work in general use cases. Following pattern appears
    frequently in applications.
    
    Parse(statement1)
    Bind(statement1, portal1)
    Execute(portal1)
    Bind(statement1, portal1)
    Execute(portal1)
    :
    :
    Sync
    
    Also what would happen if client just send a parse message and does
    nothing after that?
    
    So I think following is better:
    
    Parse(statement1)
    Bind(statement1, portal1)
    Execute(portal1)
      start timer
      stop timer
    Bind(statement1, portal1)
    Execute(portal1)
      start timer
      stop timer
    :
    :
    Sync
    
    Best regards,
    --
    Tatsuo Ishii
    SRA OSS, Inc. Japan
    English: http://www.sraoss.co.jp/index_en.php
    Japanese:http://www.sraoss.co.jp
    
    
    
  11. Re: Statement timeout behavior in extended queries

    Tsunakawa, Takayuki <tsunakawa.takay@jp.fujitsu.com> — 2017-04-04T05:24:40Z

    From: pgsql-hackers-owner@postgresql.org
    > [mailto:pgsql-hackers-owner@postgresql.org] On Behalf Of Tatsuo Ishii
    > Actually the statement timer is replaced with new statement timer value
    > in enable_statement_timeout().
    
    The patch doesn't seem to behave like that.  The Parse message calls start_xact_command() -> enable_statement_timeout() -> enable_timeout(), and set stmt_timer_started to true.  Subsequent Bind and Execute messages call enable_statement_timeout(), but enable_statement_timeout() doesn't call enable_timeout() because stmt_timer_started is already true.
    
    
    > > It looks like the patch does the following.  I think this is desirable,
    > because starting and stopping the timer for each message may be costly as
    > Tom said.
    > > Parse(statement1)
    > >   start timer
    > > Bind(statement1, portal1)
    > > Execute(portal1)
    > >   stop timer
    > > Sync
    
    I ran one INSERT statement using JDBC with log_min_messages = DEBUG3, and the server log shows what I said.
    
    DEBUG:  parse <unnamed>: insert into a values(2)
    DEBUG:  Set statement timeout
    LOG:  duration: 0.431 ms  parse <unnamed>: insert into a values(2)
    DEBUG:  bind <unnamed> to <unnamed>
    LOG:  duration: 0.127 ms  bind <unnamed>: insert into a values(2)
    DEBUG:  Disable statement timeout
    LOG:  duration: 0.184 ms  execute <unnamed>: insert into a values(2)
    DEBUG:  snapshot of 1+0 running transaction ids (lsn 0/163BF28 oldest xid 561 latest complete 560 next xid 562)
    
    
    > This doesn't work in general use cases. Following pattern appears frequently
    > in applications.
    > 
    > Parse(statement1)
    > Bind(statement1, portal1)
    > Execute(portal1)
    > Bind(statement1, portal1)
    > Execute(portal1)
    > :
    > :
    > Sync
    
    It works.  The first Parse-Bind-Execute is measured as one unit, then subsequent Bind-Execute pairs are measured as other units.  That's because each Execute ends the statement_timeout timer and the Bind message starts it again.  I think this is desirable, so the current patch looks good.  May I mark this as ready for committer?  FYI, make check-world passed successfully.
    
    
    > Also what would happen if client just send a parse message and does nothing
    > after that?
    
    It's correct to trigger the statement timeout in this case, because the first SQL statement started (with the Parse message) and its execution is not finished (with Execute message.)
    
    
    Regards
    Takayuki Tsunakawa
    
    
    
    
    
    
  12. Re: Statement timeout behavior in extended queries

    Tatsuo Ishii <ishii@sraoss.co.jp> — 2017-04-04T05:35:13Z

    > The patch doesn't seem to behave like that.  The Parse message calls start_xact_command() -> enable_statement_timeout() -> enable_timeout(), and set stmt_timer_started to true.  Subsequent Bind and Execute messages call enable_statement_timeout(), but enable_statement_timeout() doesn't call enable_timeout() because stmt_timer_started is already true.
    > 
    > 
    >> > It looks like the patch does the following.  I think this is desirable,
    >> because starting and stopping the timer for each message may be costly as
    >> Tom said.
    >> > Parse(statement1)
    >> >   start timer
    >> > Bind(statement1, portal1)
    >> > Execute(portal1)
    >> >   stop timer
    >> > Sync
    > 
    > I ran one INSERT statement using JDBC with log_min_messages = DEBUG3, and the server log shows what I said.
    > 
    > DEBUG:  parse <unnamed>: insert into a values(2)
    > DEBUG:  Set statement timeout
    > LOG:  duration: 0.431 ms  parse <unnamed>: insert into a values(2)
    > DEBUG:  bind <unnamed> to <unnamed>
    > LOG:  duration: 0.127 ms  bind <unnamed>: insert into a values(2)
    > DEBUG:  Disable statement timeout
    > LOG:  duration: 0.184 ms  execute <unnamed>: insert into a values(2)
    > DEBUG:  snapshot of 1+0 running transaction ids (lsn 0/163BF28 oldest xid 561 latest complete 560 next xid 562)
    
    Check.
    
    >> This doesn't work in general use cases. Following pattern appears frequently
    >> in applications.
    >> 
    >> Parse(statement1)
    >> Bind(statement1, portal1)
    >> Execute(portal1)
    >> Bind(statement1, portal1)
    >> Execute(portal1)
    >> :
    >> :
    >> Sync
    > 
    > It works.  The first Parse-Bind-Execute is measured as one unit, then subsequent Bind-Execute pairs are measured as other units.  That's because each Execute ends the statement_timeout timer and the Bind message starts it again.  I think this is desirable, so the current patch looks good.  May I mark this as ready for committer?  FYI, make check-world passed successfully.
    
    It's too late. Someone has already moved the patch to the next CF (for
    PostgreSQL 11).
    
    >> Also what would happen if client just send a parse message and does nothing
    >> after that?
    > 
    > It's correct to trigger the statement timeout in this case, because the first SQL statement started (with the Parse message) and its execution is not finished (with Execute message.)
    > 
    > 
    > Regards
    > Takayuki Tsunakawa
    > 
    > 
    > 
    
    
    
  13. Re: Statement timeout behavior in extended queries

    Tsunakawa, Takayuki <tsunakawa.takay@jp.fujitsu.com> — 2017-04-04T06:18:04Z

    From: Tatsuo Ishii [mailto:ishii@sraoss.co.jp]
    > It's too late. Someone has already moved the patch to the next CF (for
    > PostgreSQL 11).
    
    Yes, but this patch will be necessary by the final release of PG 10 if the libpq batch/pipelining is committed in PG 10.
    
    I marked this as ready for committer in the next CF, so that some committer can pick up this patch and consider putting it in PG 10.  If you decide to modify the patch, please change the status.
    
    Regards
    Takayuki Tsunakawa
    
    
    
    
    
    
  14. Re: Statement timeout behavior in extended queries

    Andres Freund <andres@anarazel.de> — 2017-04-04T06:26:24Z

    On 2017-04-04 06:18:04 +0000, Tsunakawa, Takayuki wrote:
    > From: Tatsuo Ishii [mailto:ishii@sraoss.co.jp]
    > > It's too late. Someone has already moved the patch to the next CF (for
    > > PostgreSQL 11).
    > 
    > Yes, but this patch will be necessary by the final release of PG 10 if the libpq batch/pipelining is committed in PG 10.
    > 
    > I marked this as ready for committer in the next CF, so that some committer can pick up this patch and consider putting it in PG 10.  If you decide to modify the patch, please change the status.
    
    Given the concern raised in http://archives.postgresql.org/message-id/12207.1491228316%40sss.pgh.pa.us
    I don't see this being ready for committer.
    
    - Andres
    
    
    
  15. Re: Statement timeout behavior in extended queries

    Tsunakawa, Takayuki <tsunakawa.takay@jp.fujitsu.com> — 2017-04-04T06:35:00Z

    From: Andres Freund [mailto:andres@anarazel.de]
    Given the concern raised in
    > http://archives.postgresql.org/message-id/12207.1491228316%40sss.pgh.p
    > a.us
    > I don't see this being ready for committer.
    
    If what Tatsuo-san said to Tom is correct (i.e. each Parse/Bind/Execute starts and stops the timer), then it's a concern and the patch should not be ready for committer.  However, the current patch is not like that -- it seems to do what others in this thread are expecting.
    
    Regards
    Takayuki Tsunakawa
    
    
    
    
  16. Re: Statement timeout behavior in extended queries

    Andres Freund <andres@anarazel.de> — 2017-04-04T06:48:20Z

    On 2017-04-04 06:35:00 +0000, Tsunakawa, Takayuki wrote:
    > From: Andres Freund [mailto:andres@anarazel.de]
    > Given the concern raised in
    > > http://archives.postgresql.org/message-id/12207.1491228316%40sss.pgh.p
    > > a.us
    > > I don't see this being ready for committer.
    > 
    > If what Tatsuo-san said to Tom is correct (i.e. each Parse/Bind/Execute starts and stops the timer), then it's a concern and the patch should not be ready for committer.  However, the current patch is not like that -- it seems to do what others in this thread are expecting.
    
    Oh, interesting - I kind of took the author's statement as, uh,
    authoritative ;).  A quick look over the patch confirms your
    understanding.
    
    I think the code needs a few clarifying comments around this, but
    otherwise seems good.  Not restarting the timeout in those cases
    obviously isn't entirely "perfect"/"correct", but a tradeoff - the
    comments should note that.
    
    Tatsuo-san, do you want to change those, and push?  I can otherwise.
    
    Unfortunately I can't move the patch back to the current CF, but I guess
    we can just mark it as committed in the next.
    
    - Andres
    
    
    
  17. Re: Statement timeout behavior in extended queries

    Tatsuo Ishii <ishii@sraoss.co.jp> — 2017-04-04T07:10:32Z

    >> If what Tatsuo-san said to Tom is correct (i.e. each Parse/Bind/Execute starts and stops the timer), then it's a concern and the patch should not be ready for committer.  However, the current patch is not like that -- it seems to do what others in this thread are expecting.
    > 
    > Oh, interesting - I kind of took the author's statement as, uh,
    > authoritative ;).  A quick look over the patch confirms your
    > understanding.
    
    Yes, Tsunakawa-san is correct. Sorry for confusion.
    
    > I think the code needs a few clarifying comments around this, but
    > otherwise seems good.  Not restarting the timeout in those cases
    > obviously isn't entirely "perfect"/"correct", but a tradeoff - the
    > comments should note that.
    > 
    > Tatsuo-san, do you want to change those, and push?  I can otherwise.
    
    Andres,
    
    If you don't mind, could you please fix the comments and push it.
    
    > Unfortunately I can't move the patch back to the current CF, but I guess
    > we can just mark it as committed in the next.
    
    That will be great.
    
    Best regards,
    --
    Tatsuo Ishii
    SRA OSS, Inc. Japan
    English: http://www.sraoss.co.jp/index_en.php
    Japanese:http://www.sraoss.co.jp
    
    
    
  18. Re: Statement timeout behavior in extended queries

    Tatsuo Ishii <ishii@sraoss.co.jp> — 2017-04-04T23:34:43Z

    Andres,
    
    >> I think the code needs a few clarifying comments around this, but
    >> otherwise seems good.  Not restarting the timeout in those cases
    >> obviously isn't entirely "perfect"/"correct", but a tradeoff - the
    >> comments should note that.
    >> 
    >> Tatsuo-san, do you want to change those, and push?  I can otherwise.
    > 
    > Andres,
    > 
    > If you don't mind, could you please fix the comments and push it.
    
    I have changed the comments as you suggested. If it's ok, I can push
    the patch myself (today I have time to work on this).
    
    Best regards,
    --
    Tatsuo Ishii
    SRA OSS, Inc. Japan
    English: http://www.sraoss.co.jp/index_en.php
    Japanese:http://www.sraoss.co.jp
    
  19. Re: Statement timeout behavior in extended queries

    Andres Freund <andres@anarazel.de> — 2017-04-04T23:38:53Z

    On 2017-04-04 16:10:32 +0900, Tatsuo Ishii wrote:
    > >> If what Tatsuo-san said to Tom is correct (i.e. each Parse/Bind/Execute starts and stops the timer), then it's a concern and the patch should not be ready for committer.  However, the current patch is not like that -- it seems to do what others in this thread are expecting.
    > > 
    > > Oh, interesting - I kind of took the author's statement as, uh,
    > > authoritative ;).  A quick look over the patch confirms your
    > > understanding.
    > 
    > Yes, Tsunakawa-san is correct. Sorry for confusion.
    > 
    > > I think the code needs a few clarifying comments around this, but
    > > otherwise seems good.  Not restarting the timeout in those cases
    > > obviously isn't entirely "perfect"/"correct", but a tradeoff - the
    > > comments should note that.
    > > 
    > > Tatsuo-san, do you want to change those, and push?  I can otherwise.
    > 
    > Andres,
    > 
    > If you don't mind, could you please fix the comments and push it.
    
    Hm. I started to edit it, but I'm halfway coming back to my previous
    view that this isn't necessarily ready.
    
    If a client were to to prepare a large number of prepared statements
    (i.e. a lot of parse messages), this'll only start the timeout once, at
    the first statement sent.  It's not an issue for libpq which sends a
    sync message after each PQprepare, nor does it look to be an issue for
    pgjdbc based on a quick look.
    
    Does anybody think there might be a driver out there that sends a bunch
    of 'parse' messages, without syncs?
    
    - Andres
    
    
    
  20. Re: Statement timeout behavior in extended queries

    Andres Freund <andres@anarazel.de> — 2017-04-04T23:42:08Z

    On 2017-04-05 08:34:43 +0900, Tatsuo Ishii wrote:
    > Andres,
    > 
    > >> I think the code needs a few clarifying comments around this, but
    > >> otherwise seems good.  Not restarting the timeout in those cases
    > >> obviously isn't entirely "perfect"/"correct", but a tradeoff - the
    > >> comments should note that.
    > >> 
    > >> Tatsuo-san, do you want to change those, and push?  I can otherwise.
    > > 
    > > Andres,
    > > 
    > > If you don't mind, could you please fix the comments and push it.
    > 
    > I have changed the comments as you suggested. If it's ok, I can push
    > the patch myself (today I have time to work on this).
    
    I'm working on the patch, and I've edited it more heavily, so please
    hold off.
    
    Changes:
    I don't think the debugging statements are a good idea, the
    !xact_started should be an assert, and disable_timeout should be called
    from within enable_statement_timeout independent of stmt_timer_started.
    
    
    But more importantly I had just sent a question that I think merits
    discussion.
    
    
    - Andres
    
    
    
  21. Re: Statement timeout behavior in extended queries

    Andres Freund <andres@anarazel.de> — 2017-04-04T23:48:51Z

    On 2017-04-04 16:38:53 -0700, Andres Freund wrote:
    > On 2017-04-04 16:10:32 +0900, Tatsuo Ishii wrote:
    > > >> If what Tatsuo-san said to Tom is correct (i.e. each Parse/Bind/Execute starts and stops the timer), then it's a concern and the patch should not be ready for committer.  However, the current patch is not like that -- it seems to do what others in this thread are expecting.
    > > > 
    > > > Oh, interesting - I kind of took the author's statement as, uh,
    > > > authoritative ;).  A quick look over the patch confirms your
    > > > understanding.
    > > 
    > > Yes, Tsunakawa-san is correct. Sorry for confusion.
    > > 
    > > > I think the code needs a few clarifying comments around this, but
    > > > otherwise seems good.  Not restarting the timeout in those cases
    > > > obviously isn't entirely "perfect"/"correct", but a tradeoff - the
    > > > comments should note that.
    > > > 
    > > > Tatsuo-san, do you want to change those, and push?  I can otherwise.
    > > 
    > > Andres,
    > > 
    > > If you don't mind, could you please fix the comments and push it.
    > 
    > Hm. I started to edit it, but I'm halfway coming back to my previous
    > view that this isn't necessarily ready.
    > 
    > If a client were to to prepare a large number of prepared statements
    > (i.e. a lot of parse messages), this'll only start the timeout once, at
    > the first statement sent.  It's not an issue for libpq which sends a
    > sync message after each PQprepare, nor does it look to be an issue for
    > pgjdbc based on a quick look.
    > 
    > Does anybody think there might be a driver out there that sends a bunch
    > of 'parse' messages, without syncs?
    
    Looks to me like npgsql doesn't do that either.  None of libpq, pgjdbs
    and npgsql doing it seems like some evidence that it's ok.
    
    - Andres
    
    
    
  22. Re: Statement timeout behavior in extended queries

    Tsunakawa, Takayuki <tsunakawa.takay@jp.fujitsu.com> — 2017-04-04T23:52:28Z

    From: Andres Freund [mailto:andres@anarazel.de]
    > Looks to me like npgsql doesn't do that either.  None of libpq, pgjdbs and
    > npgsql doing it seems like some evidence that it's ok.
    
    And psqlODBC now uses always libpq.
    
    Now time for final decision?
    
    Regards
    Takayuki Tsunakawa
    
    
    
    
    
  23. Re: Statement timeout behavior in extended queries

    Andres Freund <andres@anarazel.de> — 2017-04-04T23:56:26Z

    On 2017-04-04 23:52:28 +0000, Tsunakawa, Takayuki wrote:
    > From: Andres Freund [mailto:andres@anarazel.de]
    > > Looks to me like npgsql doesn't do that either.  None of libpq, pgjdbs and
    > > npgsql doing it seems like some evidence that it's ok.
    > 
    > And psqlODBC now uses always libpq.
    > 
    > Now time for final decision?
    
    I'll send an updated patch in a bit, and then will wait till tomorrow to
    push. Giving others a chance to chime in seems fair.
    
    - Andres
    
    
    
  24. Re: Statement timeout behavior in extended queries

    Tatsuo Ishii <ishii@sraoss.co.jp> — 2017-04-05T01:05:19Z

    > Hm. I started to edit it, but I'm halfway coming back to my previous
    > view that this isn't necessarily ready.
    > 
    > If a client were to to prepare a large number of prepared statements
    > (i.e. a lot of parse messages), this'll only start the timeout once, at
    > the first statement sent.  It's not an issue for libpq which sends a
    > sync message after each PQprepare, nor does it look to be an issue for
    > pgjdbc based on a quick look.
    > 
    > Does anybody think there might be a driver out there that sends a bunch
    > of 'parse' messages, without syncs?
    
    What's your point of the question? What kind of problem do you expect
    if the timeout starts only once at the first parse meesage out of
    bunch of parse messages?
    
    Best regards,
    --
    Tatsuo Ishii
    SRA OSS, Inc. Japan
    English: http://www.sraoss.co.jp/index_en.php
    Japanese:http://www.sraoss.co.jp
    
    
    
  25. Re: Statement timeout behavior in extended queries

    Andres Freund <andres@anarazel.de> — 2017-04-05T01:08:41Z

    On 2017-04-05 10:05:19 +0900, Tatsuo Ishii wrote:
    > > Hm. I started to edit it, but I'm halfway coming back to my previous
    > > view that this isn't necessarily ready.
    > > 
    > > If a client were to to prepare a large number of prepared statements
    > > (i.e. a lot of parse messages), this'll only start the timeout once, at
    > > the first statement sent.  It's not an issue for libpq which sends a
    > > sync message after each PQprepare, nor does it look to be an issue for
    > > pgjdbc based on a quick look.
    > > 
    > > Does anybody think there might be a driver out there that sends a bunch
    > > of 'parse' messages, without syncs?
    > 
    > What's your point of the question? What kind of problem do you expect
    > if the timeout starts only once at the first parse meesage out of
    > bunch of parse messages?
    
    It's perfectly valid to send a lot of Parse messages without
    interspersed Sync or Bind/Execute message.  There'll be one timeout
    covering all of those Parse messages, which can thus lead to a timeout,
    even though nothing actually takes long individually.
    
    Greetings,
    
    Andres Freund
    
    
    
  26. Re: Statement timeout behavior in extended queries

    Tatsuo Ishii <ishii@sraoss.co.jp> — 2017-04-05T01:22:08Z

    >> What's your point of the question? What kind of problem do you expect
    >> if the timeout starts only once at the first parse meesage out of
    >> bunch of parse messages?
    > 
    > It's perfectly valid to send a lot of Parse messages without
    > interspersed Sync or Bind/Execute message.  There'll be one timeout
    > covering all of those Parse messages, which can thus lead to a timeout,
    > even though nothing actually takes long individually.
    
    Hmm. IMO, that could happen even with the current statement timeout
    implementation as well.
    
    Or we could start/stop the timeout in exec_execute_message()
    only. This could avoid the problem above. Also this is more consistent
    with log_duration/log_min_duration_statement behavior than now.
    
    Best regards,
    --
    Tatsuo Ishii
    SRA OSS, Inc. Japan
    English: http://www.sraoss.co.jp/index_en.php
    Japanese:http://www.sraoss.co.jp
    
    
    
  27. Re: Statement timeout behavior in extended queries

    Andres Freund <andres@anarazel.de> — 2017-04-05T01:45:40Z

    On 2017-04-04 16:56:26 -0700, 'Andres Freund' wrote:
    > On 2017-04-04 23:52:28 +0000, Tsunakawa, Takayuki wrote:
    > > From: Andres Freund [mailto:andres@anarazel.de]
    > > > Looks to me like npgsql doesn't do that either.  None of libpq, pgjdbs and
    > > > npgsql doing it seems like some evidence that it's ok.
    > > 
    > > And psqlODBC now uses always libpq.
    > > 
    > > Now time for final decision?
    > 
    > I'll send an updated patch in a bit, and then will wait till tomorrow to
    > push. Giving others a chance to chime in seems fair.
    
    Attached.  I did not like that the previous patch had the timeout
    handling duplicated in the individual functions, I instead centralized
    it into start_xact_command().  Given that it already activated the
    timeout in the most common cases, that seems to make more sense to
    me. In your version we'd have called enable_statement_timeout() twice
    consecutively (which behaviourally is harmless).
    
    What do you think?  I've not really tested this with the extended
    protocol, so I'd appreciate if you could rerun your test from the
    older thread.
    
    - Andres
    
  28. Re: Statement timeout behavior in extended queries

    Tatsuo Ishii <ishii@sraoss.co.jp> — 2017-04-05T01:54:26Z

    > On 2017-04-04 16:56:26 -0700, 'Andres Freund' wrote:
    >> On 2017-04-04 23:52:28 +0000, Tsunakawa, Takayuki wrote:
    >> > From: Andres Freund [mailto:andres@anarazel.de]
    >> > > Looks to me like npgsql doesn't do that either.  None of libpq, pgjdbs and
    >> > > npgsql doing it seems like some evidence that it's ok.
    >> > 
    >> > And psqlODBC now uses always libpq.
    >> > 
    >> > Now time for final decision?
    >> 
    >> I'll send an updated patch in a bit, and then will wait till tomorrow to
    >> push. Giving others a chance to chime in seems fair.
    > 
    > Attached.  I did not like that the previous patch had the timeout
    > handling duplicated in the individual functions, I instead centralized
    > it into start_xact_command().  Given that it already activated the
    > timeout in the most common cases, that seems to make more sense to
    > me. In your version we'd have called enable_statement_timeout() twice
    > consecutively (which behaviourally is harmless).
    > 
    > What do you think?  I've not really tested this with the extended
    > protocol, so I'd appreciate if you could rerun your test from the
    > older thread.
    
    Ok, I will look into your patch and test it out using pgproto.
    
    Best regards,
    --
    Tatsuo Ishii
    SRA OSS, Inc. Japan
    English: http://www.sraoss.co.jp/index_en.php
    Japanese:http://www.sraoss.co.jp
    
    
    
  29. Re: Statement timeout behavior in extended queries

    Tsunakawa, Takayuki <tsunakawa.takay@jp.fujitsu.com> — 2017-04-05T01:55:47Z

    From: pgsql-hackers-owner@postgresql.org
    > [mailto:pgsql-hackers-owner@postgresql.org] On Behalf Of Tatsuo Ishii
    > Hmm. IMO, that could happen even with the current statement timeout
    > implementation as well.
    > 
    > Or we could start/stop the timeout in exec_execute_message() only. This
    > could avoid the problem above. Also this is more consistent with
    > log_duration/log_min_duration_statement behavior than now.
    
    I think it's better to include Parse and Bind as now.  Parse or Bind could take long time when the table has many partitions, the query is complex and/or very long, some DDL statement is running against a target table, or the system load is high.
    
    Firing statement timeout during or after many Parses is not a problem, because the first Parse started running some statement and it's not finished.  Plus, Andres confirmed that major client drivers don't use such a pattern.  There may be an odd behavior purely from the perspective of E.Q.P, that's a compromise, which Andres meant by "not perfect but."
    
    Regards
    Takayuki Tsunakawa
    
    
    
    
  30. Re: Statement timeout behavior in extended queries

    Tom Lane <tgl@sss.pgh.pa.us> — 2017-04-05T04:39:51Z

    Andres Freund <andres@anarazel.de> writes:
    > On 2017-04-05 10:05:19 +0900, Tatsuo Ishii wrote:
    >> What's your point of the question? What kind of problem do you expect
    >> if the timeout starts only once at the first parse meesage out of
    >> bunch of parse messages?
    
    > It's perfectly valid to send a lot of Parse messages without
    > interspersed Sync or Bind/Execute message.  There'll be one timeout
    > covering all of those Parse messages, which can thus lead to a timeout,
    > even though nothing actually takes long individually.
    
    It might well be reasonable to redefine statement_timeout as limiting the
    total time from the first client input to the response to Sync ... but
    if that's what we're doing, let's make sure we do it consistently.
    
    I haven't read the patch, but the comments in this thread make me fear
    that it's introducing some ad-hoc, inconsistent behavior.
    
    			regards, tom lane
    
    
    
  31. Re: Statement timeout behavior in extended queries

    Tsunakawa, Takayuki <tsunakawa.takay@jp.fujitsu.com> — 2017-04-05T05:15:12Z

    From: pgsql-hackers-owner@postgresql.org
    > [mailto:pgsql-hackers-owner@postgresql.org] On Behalf Of 'Andres Freund'
    > Attached.  I did not like that the previous patch had the timeout handling
    > duplicated in the individual functions, I instead centralized it into
    > start_xact_command().  Given that it already activated the timeout in the
    > most common cases, that seems to make more sense to me. In your version
    > we'd have called enable_statement_timeout() twice consecutively (which
    > behaviourally is harmless).
    > 
    > What do you think?  I've not really tested this with the extended protocol,
    > so I'd appreciate if you could rerun your test from the older thread.
    
    The patch looks good and cleaner.  It looks like the code works as expected.  As before, I ran one INSERT statement with PgJDBC, with gdb's breakpoints set on enable_timeout() and disable_timeout().  I confirmed that enable_timeout() is called just once at Parse message, and disable_timeout() is called just once at Execute message.
    
    I'd like to wait for Tatsuo-san's thorough testing with pgproto.
    
    Regards
    Takayuki Tsunakawa
    
    
    
    
    
  32. Re: Statement timeout behavior in extended queries

    Tatsuo Ishii <ishii@sraoss.co.jp> — 2017-04-05T05:48:57Z

    >> What do you think?  I've not really tested this with the extended protocol,
    >> so I'd appreciate if you could rerun your test from the older thread.
    > 
    > The patch looks good and cleaner.  It looks like the code works as expected.  As before, I ran one INSERT statement with PgJDBC, with gdb's breakpoints set on enable_timeout() and disable_timeout().  I confirmed that enable_timeout() is called just once at Parse message, and disable_timeout() is called just once at Execute message.
    > 
    > I'd like to wait for Tatsuo-san's thorough testing with pgproto.
    
    I have done tests using pgproto. One thing I noticed a strange
    behavior. Below is an output of pgproto. The test first set the
    timeout to 3 seconds, and parse/bind for "SELECT pg_sleep(2)" then set
    timeout to 1 second using extended query. Subsequent Execute emits a
    statement timeout error as expected, but next "SELECT pg_sleep(2)"
    call using extended query does not emit a statement error. The test
    for this is "007-timeout-twice". Attached is the test cases including
    this.
    
    FE=> Query(query="SET statement_timeout = '3s'")
    <= BE CommandComplete(SET)
    <= BE ReadyForQuery(I)
    FE=> Parse(stmt="S1", query="SELECT pg_sleep(2)")
    FE=> Bind(stmt="S1", portal="S2")
    FE=> Parse(stmt="", query="SET statement_timeout = '1s'")
    FE=> Bind(stmt="", portal="")
    FE=> Execute(portal="")
    FE=> Execute(portal="S2")
    FE=> Sync
    <= BE ParseComplete
    <= BE BindComplete
    <= BE ParseComplete
    <= BE BindComplete
    <= BE CommandComplete(SET)
    <= BE ErrorResponse(S ERROR V ERROR C 57014 M canceling statement due to statement timeout F postgres.c L 2968 R ProcessInterrupts )
    <= BE ReadyForQuery(I)
    FE=> Parse(stmt="S3", query="SELECT pg_sleep(2)")
    FE=> Bind(stmt="S3", portal="S2")
    FE=> Execute(portal="S2")
    FE=> Sync
    <= BE ParseComplete
    <= BE BindComplete
    <= BE DataRow
    <= BE CommandComplete(SELECT 1)
    <= BE ReadyForQuery(I)
    FE=> Terminate
    
    
  33. Re: Statement timeout behavior in extended queries

    Tsunakawa, Takayuki <tsunakawa.takay@jp.fujitsu.com> — 2017-04-05T06:37:35Z

    From: pgsql-hackers-owner@postgresql.org
    > [mailto:pgsql-hackers-owner@postgresql.org] On Behalf Of Tatsuo Ishii
    > I have done tests using pgproto. One thing I noticed a strange behavior.
    > Below is an output of pgproto. The test first set the timeout to 3 seconds,
    > and parse/bind for "SELECT pg_sleep(2)" then set timeout to 1 second using
    > extended query. Subsequent Execute emits a statement timeout error as
    > expected, but next "SELECT pg_sleep(2)"
    > call using extended query does not emit a statement error. The test for
    > this is "007-timeout-twice". Attached is the test cases including this.
    
    What's the handling of transactions like in pgproto?  I guess the first statement timeout error rolled back the effect of "SET statement_timeout = '1s'", and the timeout reverted to 3s or some other value.
    
    Regards
    Takayuki Tsunakawa
    
    
    
    
    
  34. Re: Statement timeout behavior in extended queries

    Tatsuo Ishii <ishii@sraoss.co.jp> — 2017-04-05T06:44:15Z

    > From: pgsql-hackers-owner@postgresql.org
    >> [mailto:pgsql-hackers-owner@postgresql.org] On Behalf Of Tatsuo Ishii
    >> I have done tests using pgproto. One thing I noticed a strange behavior.
    >> Below is an output of pgproto. The test first set the timeout to 3 seconds,
    >> and parse/bind for "SELECT pg_sleep(2)" then set timeout to 1 second using
    >> extended query. Subsequent Execute emits a statement timeout error as
    >> expected, but next "SELECT pg_sleep(2)"
    >> call using extended query does not emit a statement error. The test for
    >> this is "007-timeout-twice". Attached is the test cases including this.
    > 
    > What's the handling of transactions like in pgproto?  I guess the first statement timeout error rolled back the effect of "SET statement_timeout = '1s'", and the timeout reverted to 3s or some other value.
    
    Since pgproto is a dumb protocol machine, it does not start a
    transaction automatically (user needs to explicitly send a start
    transaction command via either simple or extended query). In this
    particular case no explicit transaction has started.
    
    Best regards,
    --
    Tatsuo Ishii
    SRA OSS, Inc. Japan
    English: http://www.sraoss.co.jp/index_en.php
    Japanese:http://www.sraoss.co.jp
    
    
    
  35. Re: Statement timeout behavior in extended queries

    Tsunakawa, Takayuki <tsunakawa.takay@jp.fujitsu.com> — 2017-04-05T07:03:02Z

    From: pgsql-hackers-owner@postgresql.org
    > [mailto:pgsql-hackers-owner@postgresql.org] On Behalf Of Tatsuo Ishii
    > Since pgproto is a dumb protocol machine, it does not start a transaction
    > automatically (user needs to explicitly send a start transaction command
    > via either simple or extended query). In this particular case no explicit
    > transaction has started.
    > 
    
    Then, the following sequence should have occurred.  The test result is valid.
    
    # Execute statement which takes 2 seconds.
    'P'	"S1"	"SELECT pg_sleep(2)"	0
      -> start transaction T1
    'B'	"S2"	"S1"	0	0	0
    
    'P'	""	"SET statement_timeout = '1s'"	0
    'B'	""	""	0	0	0
    'E'	""	0
    
    # Execute statement which takes 2 seconds (statement timeout expected).
    'E'	"S2"	0
      -> timeout error occurred, T1 aborted
    
    # Issue Sync message
    'S'
      -> rolled back T1, so statement_timeout reverted to 3s
    
    # Receive response from backend
    'Y'
    
    # Execute statement which takes 2 seconds (statement timeout expected).
    'P'	"S3"	"SELECT pg_sleep(2)"	0
      -> start transaction T2
    'B'	"S2"	"S3"	0	0	0
    'E'	"S2"	0
    
    # Issue Sync message
    'S'
      -> committed T2
    
    Regards
    Takayuki Tsunakawa
    
    
    
    
  36. Re: Statement timeout behavior in extended queries

    Andres Freund <andres@anarazel.de> — 2017-04-05T07:12:17Z

    On 2017-04-05 00:39:51 -0400, Tom Lane wrote:
    > Andres Freund <andres@anarazel.de> writes:
    > > On 2017-04-05 10:05:19 +0900, Tatsuo Ishii wrote:
    > >> What's your point of the question? What kind of problem do you expect
    > >> if the timeout starts only once at the first parse meesage out of
    > >> bunch of parse messages?
    > 
    > > It's perfectly valid to send a lot of Parse messages without
    > > interspersed Sync or Bind/Execute message.  There'll be one timeout
    > > covering all of those Parse messages, which can thus lead to a timeout,
    > > even though nothing actually takes long individually.
    > 
    > It might well be reasonable to redefine statement_timeout as limiting the
    > total time from the first client input to the response to Sync ...
    
    That's actually the current behaviour. start_xact_command arms the timer
    in the !xact_started case, and only finish_xact_command() disarms it.
    finish_xact_command() is issued for Sync messsages and simple statements.
    
    I brought the case up because what we're discussing is changing things
    so Execute resets the clock (more precisely disables it, and have it
    reenabled later).  So it'd be "fixed" for pipelined Execute statements,
    but not for pipelined Parses.  Changing things so that Parse/Bind also
    reset the timing would increase overhead - and it'd not be useful in
    practice, because Sync's are sent by the drivers that support
    pipelining when statements are prepared.
    
    
    > but
    > if that's what we're doing, let's make sure we do it consistently.
    > I haven't read the patch, but the comments in this thread make me fear
    > that it's introducing some ad-hoc, inconsistent behavior.
    
    I'm a bit worried too due to the time constraints here, but I think
    resetting the clock at Execute too actually makes a fair amount sense.
    
    Greetings,
    
    Andres Freund
    
    
    
  37. Re: Statement timeout behavior in extended queries

    Tatsuo Ishii <ishii@sraoss.co.jp> — 2017-04-05T07:18:07Z

    > Then, the following sequence should have occurred.  The test result is valid.
    
    Yes, I remembered that and was about to make a posting :-)
    
    > # Execute statement which takes 2 seconds.
    > 'P'	"S1"	"SELECT pg_sleep(2)"	0
    >   -> start transaction T1
    > 'B'	"S2"	"S1"	0	0	0
    
    Yes, an extended query automatically starts a transaction if there's
    no ongoing transaction.
    
    > 'P'	""	"SET statement_timeout = '1s'"	0
    > 'B'	""	""	0	0	0
    > 'E'	""	0
    > 
    > # Execute statement which takes 2 seconds (statement timeout expected).
    > 'E'	"S2"	0
    >   -> timeout error occurred, T1 aborted
    
    Right. The automatically started transaction is aborted and the effect
    of the set statement is canceled.
    
    In summary, as far as I know Andres's patch is working as expected.
    
    Best regards,
    --
    Tatsuo Ishii
    SRA OSS, Inc. Japan
    English: http://www.sraoss.co.jp/index_en.php
    Japanese:http://www.sraoss.co.jp
    
    
    
  38. Re: Statement timeout behavior in extended queries

    Tom Lane <tgl@sss.pgh.pa.us> — 2017-04-05T13:46:31Z

    Andres Freund <andres@anarazel.de> writes:
    > On 2017-04-05 00:39:51 -0400, Tom Lane wrote:
    >> but
    >> if that's what we're doing, let's make sure we do it consistently.
    >> I haven't read the patch, but the comments in this thread make me fear
    >> that it's introducing some ad-hoc, inconsistent behavior.
    
    > I'm a bit worried too due to the time constraints here, but I think
    > resetting the clock at Execute too actually makes a fair amount sense.
    
    Meh.  Two days before feature freeze is not the time to be introducing
    a rushed redefinition of the wire protocol --- and let's not fool
    ourselves, that is what this amounts to.  Let's push this out to v11
    and think about it more carefully.
    
    			regards, tom lane
    
    
    
  39. Re: Statement timeout behavior in extended queries

    Andres Freund <andres@anarazel.de> — 2017-04-05T14:33:17Z

    On 2017-04-05 09:46:31 -0400, Tom Lane wrote:
    > Andres Freund <andres@anarazel.de> writes:
    > > On 2017-04-05 00:39:51 -0400, Tom Lane wrote:
    > >> but
    > >> if that's what we're doing, let's make sure we do it consistently.
    > >> I haven't read the patch, but the comments in this thread make me fear
    > >> that it's introducing some ad-hoc, inconsistent behavior.
    > 
    > > I'm a bit worried too due to the time constraints here, but I think
    > > resetting the clock at Execute too actually makes a fair amount sense.
    > 
    > Meh.  Two days before feature freeze is not the time to be introducing
    > a rushed redefinition of the wire protocol --- and let's not fool
    > ourselves, that is what this amounts to.  Let's push this out to v11
    > and think about it more carefully.
    
    What I was trying to say is that I think the change makes sense and
    isn't particularly ad-hoc, but that I don't think we need to force this
    for v10.
    
    Greetings,
    
    Andres Freund
    
    
    
  40. Re: Statement timeout behavior in extended queries

    Tatsuo Ishii <ishii@sraoss.co.jp> — 2017-09-05T02:30:28Z

    > What do you think?  I've not really tested this with the extended
    > protocol, so I'd appreciate if you could rerun your test from the
    > older thread.
    
    Attached is your patch just rebased against master branch.
    
    Also I attached the test cases and results using pgproto on patched
    master branch. All looks good to me.
    
    Best regards,
    --
    Tatsuo Ishii
    SRA OSS, Inc. Japan
    English: http://www.sraoss.co.jp/index_en.php
    Japanese:http://www.sraoss.co.jp
    
  41. Re: Statement timeout behavior in extended queries

    Tatsuo Ishii <ishii@sraoss.co.jp> — 2017-09-11T00:10:49Z

    Andres,
    
    If you don't mind, can you please commit/push the patch?
    
    Best regards,
    --
    Tatsuo Ishii
    SRA OSS, Inc. Japan
    English: http://www.sraoss.co.jp/index_en.php
    Japanese:http://www.sraoss.co.jp
    
    >> What do you think?  I've not really tested this with the extended
    >> protocol, so I'd appreciate if you could rerun your test from the
    >> older thread.
    > 
    > Attached is your patch just rebased against master branch.
    > 
    > Also I attached the test cases and results using pgproto on patched
    > master branch. All looks good to me.
    > 
    > Best regards,
    > --
    > Tatsuo Ishii
    > SRA OSS, Inc. Japan
    > English: http://www.sraoss.co.jp/index_en.php
    > Japanese:http://www.sraoss.co.jp
    
    
    
  42. Re: Statement timeout behavior in extended queries

    Andres Freund <andres@anarazel.de> — 2017-09-11T00:12:19Z

    Hi,
    
    On 2017-09-11 09:10:49 +0900, Tatsuo Ishii wrote:
    > If you don't mind, can you please commit/push the patch?
    
    Ok, will do so.
    
    Greetings,
    
    Andres Freund
    
    
    
  43. Re: Statement timeout behavior in extended queries

    Andres Freund <andres@anarazel.de> — 2017-09-19T02:41:27Z

    On 2017-09-10 17:12:19 -0700, Andres Freund wrote:
    > On 2017-09-11 09:10:49 +0900, Tatsuo Ishii wrote:
    > > If you don't mind, can you please commit/push the patch?
    > 
    > Ok, will do so.
    
    And, done.  Thanks for patch and reminder!
    
    - Andres
    
    
    
  44. Re: Statement timeout behavior in extended queries

    Tatsuo Ishii <ishii@sraoss.co.jp> — 2017-09-19T02:42:38Z

    > On 2017-09-10 17:12:19 -0700, Andres Freund wrote:
    >> On 2017-09-11 09:10:49 +0900, Tatsuo Ishii wrote:
    >> > If you don't mind, can you please commit/push the patch?
    >> 
    >> Ok, will do so.
    > 
    > And, done.  Thanks for patch and reminder!
    
    Thanks!
    --
    Tatsuo Ishii
    SRA OSS, Inc. Japan
    English: http://www.sraoss.co.jp/index_en.php
    Japanese:http://www.sraoss.co.jp