Re: [GENERAL] Momentary Delay
On Wed, 17 Jun 2015 10:33:37 -0300 Anderson Valadares anderva...@gmail.com wrote: 2015-06-15 18:19 GMT-03:00 Bill Moran wmo...@potentialtech.com: On Mon, 15 Jun 2015 17:48:54 -0300 Anderson Valadares anderva...@gmail.com wrote: 2015-06-12 19:56 GMT-03:00 Bill Moran wmo...@potentialtech.com: Please do not remove the mailing list from replies. See below. On Fri, 12 Jun 2015 09:21:19 -0300 Anderson Valadares anderva...@gmail.com wrote: 2015-06-08 20:33 GMT-03:00 Bill Moran wmo...@potentialtech.com: On Mon, 8 Jun 2015 11:59:31 -0300 Anderson Valadares anderva...@gmail.com wrote: Hi We are experiencing an intermittent problem in a GIS database from a client. Some times of the day is as if the PostgreSQL executed the slowest operations see below an example. The query was performed three times, twice I canceled and the third time I left it to end. The consultation took 10 seconds to finish, but the measured execution time is 20 ms. As we have several queries that run every 2 seconds when this momentary delay occurs queries accumulate and burst the limit of 203 connections allowed. The interval of momentary stop are approximately 2 seconds occurring at random times and during these stoppages occur no locks and no increased load on the server is identified. There is a job 2/2 seconds locks collection of information, running queries, etc., nmon also collects information every 2 seconds. My client asks what causes these momentary stops? because it affects all operations of the database? etc. How do I identify what is causing these delays in executions of operations in the database? Number of points to consider: * Check the contents of pg_locks and see if something is waiting on a lock when the query is slow. There is nothing waiting when the query is slow, see: snap_datetime | waiting | count ---+-+--- 2015-06-05 09:25:00.954731-03 | f |74 2015-06-05 09:26:00.249187-03 | f | 205 2015-06-05 09:27:00.826874-03 | f | 207 I don't know what that means. Since you don't show the query that generated that output, I have no idea if your statement is valid, or if you're running a query that will inherently produce incorrect results. Sorry the information was incomplete. Below is the query that was performed to extract information from tables that used to monitor the database. The snap_datetime column indicates the time that occurred monitoring, the waiting column tells you whether any connection was on hold and the column count tells how many connections existed at the time. select s.snap_datetime ,a.waiting , count(*) from stat_snapshot s, stat_activity a where s.snap_id = a.snap_id and s.snap_datetime = '2015-06-05 09:25:00' and s.snap_datetime = '2015-06-05 09:28:00' group by s.snap_datetime ,a.waiting order by s.snap_datetime ; snap_datetime | waiting | count ---+-+--- 2015-06-05 09:25:00.954731-03 | f |74 2015-06-05 09:26:00.249187-03 | f | 205 2015-06-05 09:27:00.826874-03 | f | 207 (3 rows) Given what I'm seeing above, there's still a lot of information missing. Those tables are not standard PostgreSQL tables, and I'm not aware of any tool that creates them, thus I have to assume it's a cron job or something similar created in-house. Given the query you ran and the resultant data, my first guess is that the data in stat_snapshot and stat_activity is worthless: i.e. it's captured once per minute, and therefore there are 59+ seconds worth of detail that aren't captured, thus the actual liklihood that the those tables will contain any indication of the problem is very low. Yes it is a cron, created at home, running every 1 hour gathering information from PostgreSQL tables (pg_stat_activity, pg_locks, etc). How to improve the collection of information PostgreSQL? Look at the log file, details of what is going on are being recorded as they happen. However, given your statement below (claiming that nothing happened during the observed slowdown between 9:26 and 9:27) you may want to find someone who is actually capable of interpreting the log output, as there are dozens of indicators of what's wrong. Immediately after the problem disappears, a number of queries finish after spending a lot of time executing, in addition to a number of complaints of long lock waits. So all those queries were fighting each other and when they finally untangled themselves and got their work done,
Re: [GENERAL] Momentary Delay
2015-06-15 18:19 GMT-03:00 Bill Moran wmo...@potentialtech.com: On Mon, 15 Jun 2015 17:48:54 -0300 Anderson Valadares anderva...@gmail.com wrote: 2015-06-12 19:56 GMT-03:00 Bill Moran wmo...@potentialtech.com: Please do not remove the mailing list from replies. See below. On Fri, 12 Jun 2015 09:21:19 -0300 Anderson Valadares anderva...@gmail.com wrote: 2015-06-08 20:33 GMT-03:00 Bill Moran wmo...@potentialtech.com: On Mon, 8 Jun 2015 11:59:31 -0300 Anderson Valadares anderva...@gmail.com wrote: Hi We are experiencing an intermittent problem in a GIS database from a client. Some times of the day is as if the PostgreSQL executed the slowest operations see below an example. The query was performed three times, twice I canceled and the third time I left it to end. The consultation took 10 seconds to finish, but the measured execution time is 20 ms. As we have several queries that run every 2 seconds when this momentary delay occurs queries accumulate and burst the limit of 203 connections allowed. The interval of momentary stop are approximately 2 seconds occurring at random times and during these stoppages occur no locks and no increased load on the server is identified. There is a job 2/2 seconds locks collection of information, running queries, etc., nmon also collects information every 2 seconds. My client asks what causes these momentary stops? because it affects all operations of the database? etc. How do I identify what is causing these delays in executions of operations in the database? Number of points to consider: * Check the contents of pg_locks and see if something is waiting on a lock when the query is slow. There is nothing waiting when the query is slow, see: snap_datetime | waiting | count ---+-+--- 2015-06-05 09:25:00.954731-03 | f |74 2015-06-05 09:26:00.249187-03 | f | 205 2015-06-05 09:27:00.826874-03 | f | 207 I don't know what that means. Since you don't show the query that generated that output, I have no idea if your statement is valid, or if you're running a query that will inherently produce incorrect results. Sorry the information was incomplete. Below is the query that was performed to extract information from tables that used to monitor the database. The snap_datetime column indicates the time that occurred monitoring, the waiting column tells you whether any connection was on hold and the column count tells how many connections existed at the time. select s.snap_datetime ,a.waiting , count(*) from stat_snapshot s, stat_activity a where s.snap_id = a.snap_id and s.snap_datetime = '2015-06-05 09:25:00' and s.snap_datetime = '2015-06-05 09:28:00' group by s.snap_datetime ,a.waiting order by s.snap_datetime ; snap_datetime | waiting | count ---+-+--- 2015-06-05 09:25:00.954731-03 | f |74 2015-06-05 09:26:00.249187-03 | f | 205 2015-06-05 09:27:00.826874-03 | f | 207 (3 rows) Given what I'm seeing above, there's still a lot of information missing. Those tables are not standard PostgreSQL tables, and I'm not aware of any tool that creates them, thus I have to assume it's a cron job or something similar created in-house. Given the query you ran and the resultant data, my first guess is that the data in stat_snapshot and stat_activity is worthless: i.e. it's captured once per minute, and therefore there are 59+ seconds worth of detail that aren't captured, thus the actual liklihood that the those tables will contain any indication of the problem is very low. Yes it is a cron, created at home, running every 1 hour gathering information from PostgreSQL tables (pg_stat_activity, pg_locks, etc). How to improve the collection of information PostgreSQL? * Also, ensure log_lock_waits is turned on for the server and check PostgreSQL's logs for messages about long lock waits. There is also nothing This is even worse than the previous statement. What did you _do_ to determine this? Since you're unable to diagnose and fix the problem on your own, the possibility exists that the problem is with your diagnostic steps. If you don't share the details of those steps, I have no way to help you with them. See the log in https://github.com/andervalbh/serv-gis01/blob/master/postgresql-2015-06-05_00.log Apologies, my above comment was intended to be in regards to the IO load. However, that log shows that you have massive lock contention. In the early part of the log a process waits over 5 minutes for a share lock:
Re: [GENERAL] Momentary Delay
2015-06-12 19:56 GMT-03:00 Bill Moran wmo...@potentialtech.com: Please do not remove the mailing list from replies. See below. On Fri, 12 Jun 2015 09:21:19 -0300 Anderson Valadares anderva...@gmail.com wrote: 2015-06-08 20:33 GMT-03:00 Bill Moran wmo...@potentialtech.com: On Mon, 8 Jun 2015 11:59:31 -0300 Anderson Valadares anderva...@gmail.com wrote: Hi We are experiencing an intermittent problem in a GIS database from a client. Some times of the day is as if the PostgreSQL executed the slowest operations see below an example. The query was performed three times, twice I canceled and the third time I left it to end. The consultation took 10 seconds to finish, but the measured execution time is 20 ms. As we have several queries that run every 2 seconds when this momentary delay occurs queries accumulate and burst the limit of 203 connections allowed. The interval of momentary stop are approximately 2 seconds occurring at random times and during these stoppages occur no locks and no increased load on the server is identified. There is a job 2/2 seconds locks collection of information, running queries, etc., nmon also collects information every 2 seconds. My client asks what causes these momentary stops? because it affects all operations of the database? etc. How do I identify what is causing these delays in executions of operations in the database? Number of points to consider: * Check the contents of pg_locks and see if something is waiting on a lock when the query is slow. There is nothing waiting when the query is slow, see: snap_datetime | waiting | count ---+-+--- 2015-06-05 09:25:00.954731-03 | f |74 2015-06-05 09:26:00.249187-03 | f | 205 2015-06-05 09:27:00.826874-03 | f | 207 I don't know what that means. Since you don't show the query that generated that output, I have no idea if your statement is valid, or if you're running a query that will inherently produce incorrect results. Sorry the information was incomplete. Below is the query that was performed to extract information from tables that used to monitor the database. The snap_datetime column indicates the time that occurred monitoring, the waiting column tells you whether any connection was on hold and the column count tells how many connections existed at the time. select s.snap_datetime ,a.waiting , count(*) from stat_snapshot s, stat_activity a where s.snap_id = a.snap_id and s.snap_datetime = '2015-06-05 09:25:00' and s.snap_datetime = '2015-06-05 09:28:00' group by s.snap_datetime ,a.waiting order by s.snap_datetime ; snap_datetime | waiting | count ---+-+--- 2015-06-05 09:25:00.954731-03 | f |74 2015-06-05 09:26:00.249187-03 | f | 205 2015-06-05 09:27:00.826874-03 | f | 207 (3 rows) * Also, ensure log_lock_waits is turned on for the server and check PostgreSQL's logs for messages about long lock waits. There is also nothing This is even worse than the previous statement. What did you _do_ to determine this? Since you're unable to diagnose and fix the problem on your own, the possibility exists that the problem is with your diagnostic steps. If you don't share the details of those steps, I have no way to help you with them. See the log in https://github.com/andervalbh/serv-gis01/blob/master/postgresql-2015-06-05_00.log * Based on the connection behavior you describe, I'm guessing it's a Tomcat app using some sort of conection pool. Whatever it is, tune your connection pool settings so that the max size of the pool doesn't exceed the available PostgreSQL connections. At least that will prevent errors from happening when the problem occurs. Yes it is a tomcat application using connection pooling and will be set to not exceed the limit of PostgreSQL connections, but the central point is that the number of connections has increased due to what I am calling momentary stoppages I understand that. I made the suggestion as a temporary fix to reduce the impact until you are able to fix the actual cause. * The query you you keep cancelling below, run just EXPLAIN on it (not EXPLAIN ANALYZE) which will certainly finish and give you a plan that can be reviewed to help determine what the problem is. Explain plan in http://explain.depesz.com/s/bWw I'm confused. The query at that URL only took 10ms to complete, which doesn't seem at all unreasonable. I agree with you and that's why I ask why the delay in the execution at certain times as demonstrated above. * On the OS, monitor iostat or something else to see if you're saturating disk capacity when the problem happens. The OS is also being monitored and
Re: [GENERAL] Momentary Delay
On Mon, 15 Jun 2015 17:48:54 -0300 Anderson Valadares anderva...@gmail.com wrote: 2015-06-12 19:56 GMT-03:00 Bill Moran wmo...@potentialtech.com: Please do not remove the mailing list from replies. See below. On Fri, 12 Jun 2015 09:21:19 -0300 Anderson Valadares anderva...@gmail.com wrote: 2015-06-08 20:33 GMT-03:00 Bill Moran wmo...@potentialtech.com: On Mon, 8 Jun 2015 11:59:31 -0300 Anderson Valadares anderva...@gmail.com wrote: Hi We are experiencing an intermittent problem in a GIS database from a client. Some times of the day is as if the PostgreSQL executed the slowest operations see below an example. The query was performed three times, twice I canceled and the third time I left it to end. The consultation took 10 seconds to finish, but the measured execution time is 20 ms. As we have several queries that run every 2 seconds when this momentary delay occurs queries accumulate and burst the limit of 203 connections allowed. The interval of momentary stop are approximately 2 seconds occurring at random times and during these stoppages occur no locks and no increased load on the server is identified. There is a job 2/2 seconds locks collection of information, running queries, etc., nmon also collects information every 2 seconds. My client asks what causes these momentary stops? because it affects all operations of the database? etc. How do I identify what is causing these delays in executions of operations in the database? Number of points to consider: * Check the contents of pg_locks and see if something is waiting on a lock when the query is slow. There is nothing waiting when the query is slow, see: snap_datetime | waiting | count ---+-+--- 2015-06-05 09:25:00.954731-03 | f |74 2015-06-05 09:26:00.249187-03 | f | 205 2015-06-05 09:27:00.826874-03 | f | 207 I don't know what that means. Since you don't show the query that generated that output, I have no idea if your statement is valid, or if you're running a query that will inherently produce incorrect results. Sorry the information was incomplete. Below is the query that was performed to extract information from tables that used to monitor the database. The snap_datetime column indicates the time that occurred monitoring, the waiting column tells you whether any connection was on hold and the column count tells how many connections existed at the time. select s.snap_datetime ,a.waiting , count(*) from stat_snapshot s, stat_activity a where s.snap_id = a.snap_id and s.snap_datetime = '2015-06-05 09:25:00' and s.snap_datetime = '2015-06-05 09:28:00' group by s.snap_datetime ,a.waiting order by s.snap_datetime ; snap_datetime | waiting | count ---+-+--- 2015-06-05 09:25:00.954731-03 | f |74 2015-06-05 09:26:00.249187-03 | f | 205 2015-06-05 09:27:00.826874-03 | f | 207 (3 rows) Given what I'm seeing above, there's still a lot of information missing. Those tables are not standard PostgreSQL tables, and I'm not aware of any tool that creates them, thus I have to assume it's a cron job or something similar created in-house. Given the query you ran and the resultant data, my first guess is that the data in stat_snapshot and stat_activity is worthless: i.e. it's captured once per minute, and therefore there are 59+ seconds worth of detail that aren't captured, thus the actual liklihood that the those tables will contain any indication of the problem is very low. * Also, ensure log_lock_waits is turned on for the server and check PostgreSQL's logs for messages about long lock waits. There is also nothing This is even worse than the previous statement. What did you _do_ to determine this? Since you're unable to diagnose and fix the problem on your own, the possibility exists that the problem is with your diagnostic steps. If you don't share the details of those steps, I have no way to help you with them. See the log in https://github.com/andervalbh/serv-gis01/blob/master/postgresql-2015-06-05_00.log Apologies, my above comment was intended to be in regards to the IO load. However, that log shows that you have massive lock contention. In the early part of the log a process waits over 5 minutes for a share lock: 2015-06-05 05:51:32 BRT [44236822] - [10.57.1.26] [14-1] db=citgis,user=opegis LOG: process 44236822 acquired ShareLock on transaction 3090377758 after 374146.817 ms Without seeing the source of the PL/pgSQL functions that seem to be causing the problem, I can only suggest that you review those functions for excessive locking and inefficient access. I'm going to guess, with the
Re: [GENERAL] Momentary Delay
Please do not remove the mailing list from replies. See below. On Fri, 12 Jun 2015 09:21:19 -0300 Anderson Valadares anderva...@gmail.com wrote: 2015-06-08 20:33 GMT-03:00 Bill Moran wmo...@potentialtech.com: On Mon, 8 Jun 2015 11:59:31 -0300 Anderson Valadares anderva...@gmail.com wrote: Hi We are experiencing an intermittent problem in a GIS database from a client. Some times of the day is as if the PostgreSQL executed the slowest operations see below an example. The query was performed three times, twice I canceled and the third time I left it to end. The consultation took 10 seconds to finish, but the measured execution time is 20 ms. As we have several queries that run every 2 seconds when this momentary delay occurs queries accumulate and burst the limit of 203 connections allowed. The interval of momentary stop are approximately 2 seconds occurring at random times and during these stoppages occur no locks and no increased load on the server is identified. There is a job 2/2 seconds locks collection of information, running queries, etc., nmon also collects information every 2 seconds. My client asks what causes these momentary stops? because it affects all operations of the database? etc. How do I identify what is causing these delays in executions of operations in the database? Number of points to consider: * Check the contents of pg_locks and see if something is waiting on a lock when the query is slow. There is nothing waiting when the query is slow, see: snap_datetime | waiting | count ---+-+--- 2015-06-05 09:25:00.954731-03 | f |74 2015-06-05 09:26:00.249187-03 | f | 205 2015-06-05 09:27:00.826874-03 | f | 207 I don't know what that means. Since you don't show the query that generated that output, I have no idea if your statement is valid, or if you're running a query that will inherently produce incorrect results. * Also, ensure log_lock_waits is turned on for the server and check PostgreSQL's logs for messages about long lock waits. There is also nothing This is even worse than the previous statement. What did you _do_ to determine this? Since you're unable to diagnose and fix the problem on your own, the possibility exists that the problem is with your diagnostic steps. If you don't share the details of those steps, I have no way to help you with them. * Based on the connection behavior you describe, I'm guessing it's a Tomcat app using some sort of conection pool. Whatever it is, tune your connection pool settings so that the max size of the pool doesn't exceed the available PostgreSQL connections. At least that will prevent errors from happening when the problem occurs. Yes it is a tomcat application using connection pooling and will be set to not exceed the limit of PostgreSQL connections, but the central point is that the number of connections has increased due to what I am calling momentary stoppages I understand that. I made the suggestion as a temporary fix to reduce the impact until you are able to fix the actual cause. * The query you you keep cancelling below, run just EXPLAIN on it (not EXPLAIN ANALYZE) which will certainly finish and give you a plan that can be reviewed to help determine what the problem is. Explain plan in http://explain.depesz.com/s/bWw I'm confused. The query at that URL only took 10ms to complete, which doesn't seem at all unreasonable. * On the OS, monitor iostat or something else to see if you're saturating disk capacity when the problem happens. The OS is also being monitored and there occurs no saturation. Again, without any details, it's possible that there is a problem in your monitoring. The Server is a IBM P720 128G RAM PostgreSQL 9.2.9 on powerpc-ibm-aix7.1.0.0, compiled by gcc (GCC) 4.6.4, 64-bit Evolution of the number of connections for a period snap_datetime| #connections --+- 2015-06-05 09:25:00.954731-03 | 74 2015-06-05 09:26:00.249187-03 | 205 2015-06-05 09:27:00.826874-03 | 207 2015-06-05 09:28:00.374666-03 | 73 2015-06-05 09:29:00.690696-03 | 75 Occurrence of the problem citgis=# select max(dvi_sub.dvi_cod_dados_via_iti) as dvi_cod_dados_via_iti, dvi_sub.via_cod_viagem from gis_dvi_dados_viagem_itinerario dvi_sub, gis_via_viagem via_sub, gis_iti_itinerario iti_sub where dvi_sub.via_cod_viagem = via_sub.via_cod_viagem and via_sub.via_status_viagem = 'A' and via_sub.via_dt_hora_ini now() - interval '9 hours' and iti_sub.lin_cod_linha = 389 and iti_sub.iti_sentido_itinerario = 'I' and iti_sub.iti_cod_itinerario_linha =
Re: [GENERAL] Momentary Delay
2015-06-08 13:58 GMT-03:00 Adrian Klaver adrian.kla...@aklaver.com: On 06/08/2015 09:25 AM, Anderson Valadares wrote: 2015-06-08 12:30 GMT-03:00 Adrian Klaver adrian.kla...@aklaver.com mailto:adrian.kla...@aklaver.com: Adrian forgiveness for my english the meant Exists a job run every 2 seconds capturing information of locks, long running queries, etc. So have you looked at the Postgres logs during these time periods to see if there is anything relevant? Anderson -- Adrian Klaver adrian.kla...@aklaver.com I saw the logs and there is nothing wrong.
Re: [GENERAL] Momentary Delay
On 06/08/2015 09:25 AM, Anderson Valadares wrote: 2015-06-08 12:30 GMT-03:00 Adrian Klaver adrian.kla...@aklaver.com mailto:adrian.kla...@aklaver.com: Adrian forgiveness for my english the meant Exists a job run every 2 seconds capturing information of locks, long running queries, etc. So have you looked at the Postgres logs during these time periods to see if there is anything relevant? Anderson -- Adrian Klaver adrian.kla...@aklaver.com -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
Re: [GENERAL] Momentary Delay
On Mon, 8 Jun 2015 11:59:31 -0300 Anderson Valadares anderva...@gmail.com wrote: Hi We are experiencing an intermittent problem in a GIS database from a client. Some times of the day is as if the PostgreSQL executed the slowest operations see below an example. The query was performed three times, twice I canceled and the third time I left it to end. The consultation took 10 seconds to finish, but the measured execution time is 20 ms. As we have several queries that run every 2 seconds when this momentary delay occurs queries accumulate and burst the limit of 203 connections allowed. The interval of momentary stop are approximately 2 seconds occurring at random times and during these stoppages occur no locks and no increased load on the server is identified. There is a job 2/2 seconds locks collection of information, running queries, etc., nmon also collects information every 2 seconds. My client asks what causes these momentary stops? because it affects all operations of the database? etc. How do I identify what is causing these delays in executions of operations in the database? Number of points to consider: * Check the contents of pg_locks and see if something is waiting on a lock when the query is slow. * Also, ensure log_lock_waits is turned on for the server and check PostgreSQL's logs for messages about long lock waits. * Make sure shared_buffers isn't larger than 16G. I've seen issues with PG 9.X and shared_buffers settings larger than that causing intermittant stalls. * Based on the connection behavior you describe, I'm guessing it's a Tomcat app using some sort of conection pool. Whatever it is, tune your connection pool settings so that the max size of the pool doesn't exceed the available PostgreSQL connections. At least that will prevent errors from happening when the problem occurs. * The query you you keep cancelling below, run judy EXPLAIN on it (not EXPLAIN ANALYZE) which will certainly finish and give you a plan that can be reviewed to help determine what the problem is. * On the OS, monitor iostat or something else to see if you're saturating disk capacity when the problem happens. The Server is a IBM P720 128G RAM PostgreSQL 9.2.9 on powerpc-ibm-aix7.1.0.0, compiled by gcc (GCC) 4.6.4, 64-bit Evolution of the number of connections for a period snap_datetime| #connections --+- 2015-06-05 09:25:00.954731-03 | 74 2015-06-05 09:26:00.249187-03 | 205 2015-06-05 09:27:00.826874-03 | 207 2015-06-05 09:28:00.374666-03 | 73 2015-06-05 09:29:00.690696-03 | 75 Occurrence of the problem citgis=# select max(dvi_sub.dvi_cod_dados_via_iti) as dvi_cod_dados_via_iti, dvi_sub.via_cod_viagem from gis_dvi_dados_viagem_itinerario dvi_sub, gis_via_viagem via_sub, gis_iti_itinerario iti_sub where dvi_sub.via_cod_viagem = via_sub.via_cod_viagem and via_sub.via_status_viagem = 'A' and via_sub.via_dt_hora_ini now() - interval '9 hours' and iti_sub.lin_cod_linha = 389 and iti_sub.iti_sentido_itinerario = 'I' and iti_sub.iti_cod_itinerario_linha = via_sub.iti_cod_itinerario_linha and dvi_sub.vlo_cod_localizacao is not null group by dvi_sub.via_cod_viagem, iti_sub.iti_cod_itinerario_linha, via_sub.equ_cod_eqpto ; Cancel request sent ERROR: canceling statement due to user request Time: 2555.557 ms citgis=# select max(dvi_sub.dvi_cod_dados_via_iti) as dvi_cod_dados_via_iti, dvi_sub.via_cod_viagem from gis_dvi_dados_viagem_itinerario dvi_sub, gis_via_viagem via_sub, gis_iti_itinerario iti_sub where dvi_sub.via_cod_viagem = via_sub.via_cod_viagem and via_sub.via_status_viagem = 'A' and via_sub.via_dt_hora_ini now() - interval '9 hours' and iti_sub.lin_cod_linha = 389 and iti_sub.iti_sentido_itinerario = 'I' and iti_sub.iti_cod_itinerario_linha = via_sub.iti_cod_itinerario_linha and dvi_sub.vlo_cod_localizacao is not null group by dvi_sub.via_cod_viagem, iti_sub.iti_cod_itinerario_linha, via_sub.equ_cod_eqpto ; Cancel request sent ERROR: canceling statement due to user request Time: 2192.572 ms citgis=# explain analyze select max(dvi_sub.dvi_cod_dados_via_iti) as dvi_cod_dados_via_iti, dvi_sub.via_cod_viagem from gis_dvi_dados_viagem_itinerario dvi_sub, gis_via_viagem via_sub, gis_iti_itinerario iti_sub where dvi_sub.via_cod_viagem = via_sub.via_cod_viagem and via_sub.via_status_viagem = 'A' and via_sub.via_dt_hora_ini now() - interval '9 hours' and iti_sub.lin_cod_linha = 389 and iti_sub.iti_sentido_itinerario = 'I' and
Re: [GENERAL] Momentary Delay
On 06/08/2015 07:59 AM, Anderson Valadares wrote: Hi We are experiencing an intermittent problem in a GIS database from a client. Some times of the day is as if the PostgreSQL executed the slowest operations see below an example. The query was performed three times, twice I canceled and the third time I left it to end. The consultation took 10 seconds to finish, but the measured execution time is 20 ms. As we have several queries that run every 2 seconds when this momentary delay occurs queries accumulate and burst the limit of 203 connections allowed. The interval of momentary stop are approximately 2 seconds occurring at random times and during these stoppages occur no locks and no increased load on the server is identified. There is a job 2/2 seconds locks collection of information, running queries, etc., nmon also collects information every 2 seconds. I do not have an answer, but I do have a question. What does: There is a job 2/2 seconds locks collection of information, running queries, etc mean? My client asks what causes these momentary stops? because it affects all operations of the database? etc. How do I identify what is causing these delays in executions of operations in the database? The Server is a IBM P720 128G RAM PostgreSQL 9.2.9 on powerpc-ibm-aix7.1.0.0, compiled by gcc (GCC) 4.6.4, 64-bit Evolution of the number of connections for a period snap_datetime | #connections --+- 2015-06-05 09:25:00.954731-03 |74 2015-06-05 09:26:00.249187-03 |205 2015-06-05 09:27:00.826874-03 |207 2015-06-05 09:28:00.374666-03 |73 2015-06-05 09:29:00.690696-03 |75 Occurrence of the problem citgis=# select max(dvi_sub.dvi_cod_dados_via_iti) as dvi_cod_dados_via_iti, dvi_sub.via_cod_viagem from gis_dvi_dados_viagem_itinerario dvi_sub, gis_via_viagem via_sub, gis_iti_itinerario iti_sub where dvi_sub.via_cod_viagem = via_sub.via_cod_viagem and via_sub.via_status_viagem = 'A' and via_sub.via_dt_hora_ini now() - interval '9 hours' and iti_sub.lin_cod_linha = 389 and iti_sub.iti_sentido_itinerario = 'I' and iti_sub.iti_cod_itinerario_linha = via_sub.iti_cod_itinerario_linha and dvi_sub.vlo_cod_localizacao is not null group by dvi_sub.via_cod_viagem, iti_sub.iti_cod_itinerario_linha, via_sub.equ_cod_eqpto ; Cancel request sent ERROR: canceling statement due to user request Time: 2555.557 ms citgis=# select max(dvi_sub.dvi_cod_dados_via_iti) as dvi_cod_dados_via_iti, dvi_sub.via_cod_viagem from gis_dvi_dados_viagem_itinerario dvi_sub, gis_via_viagem via_sub, gis_iti_itinerario iti_sub where dvi_sub.via_cod_viagem = via_sub.via_cod_viagem and via_sub.via_status_viagem = 'A' and via_sub.via_dt_hora_ini now() - interval '9 hours' and iti_sub.lin_cod_linha = 389 and iti_sub.iti_sentido_itinerario = 'I' and iti_sub.iti_cod_itinerario_linha = via_sub.iti_cod_itinerario_linha and dvi_sub.vlo_cod_localizacao is not null group by dvi_sub.via_cod_viagem, iti_sub.iti_cod_itinerario_linha, via_sub.equ_cod_eqpto ; Cancel request sent ERROR: canceling statement due to user request Time: 2192.572 ms citgis=# explain analyze select max(dvi_sub.dvi_cod_dados_via_iti) as dvi_cod_dados_via_iti, dvi_sub.via_cod_viagem from gis_dvi_dados_viagem_itinerario dvi_sub, gis_via_viagem via_sub, gis_iti_itinerario iti_sub where dvi_sub.via_cod_viagem = via_sub.via_cod_viagem and via_sub.via_status_viagem = 'A' and via_sub.via_dt_hora_ini now() - interval '9 hours' and iti_sub.lin_cod_linha = 389 and iti_sub.iti_sentido_itinerario = 'I' and iti_sub.iti_cod_itinerario_linha = via_sub.iti_cod_itinerario_linha and dvi_sub.vlo_cod_localizacao is not null group by dvi_sub.via_cod_viagem, iti_sub.iti_cod_itinerario_linha, via_sub.equ_cod_eqpto ; Cancel request sent ERROR: canceling statement due to user request Time: 10164.015 ms citgis=# select now(); now --- 2015-06-05 09:27:22.006072-03 (1 row) Time: 0.152 ms citgis=# select max(dvi_sub.dvi_cod_dados_via_iti) as dvi_cod_dados_via_iti, dvi_sub.via_cod_viagem from gis_dvi_dados_viagem_itinerario dvi_sub, gis_via_viagem via_sub, gis_iti_itinerario iti_sub where dvi_sub.via_cod_viagem = via_sub.via_cod_viagem and via_sub.via_status_viagem = 'A' and via_sub.via_dt_hora_ini now() - interval '9 hours' and iti_sub.lin_cod_linha = 389 and iti_sub.iti_sentido_itinerario = 'I' and
[GENERAL] Momentary Delay
Hi We are experiencing an intermittent problem in a GIS database from a client. Some times of the day is as if the PostgreSQL executed the slowest operations see below an example. The query was performed three times, twice I canceled and the third time I left it to end. The consultation took 10 seconds to finish, but the measured execution time is 20 ms. As we have several queries that run every 2 seconds when this momentary delay occurs queries accumulate and burst the limit of 203 connections allowed. The interval of momentary stop are approximately 2 seconds occurring at random times and during these stoppages occur no locks and no increased load on the server is identified. There is a job 2/2 seconds locks collection of information, running queries, etc., nmon also collects information every 2 seconds. My client asks what causes these momentary stops? because it affects all operations of the database? etc. How do I identify what is causing these delays in executions of operations in the database? The Server is a IBM P720 128G RAM PostgreSQL 9.2.9 on powerpc-ibm-aix7.1.0.0, compiled by gcc (GCC) 4.6.4, 64-bit Evolution of the number of connections for a period snap_datetime| #connections --+- 2015-06-05 09:25:00.954731-03 | 74 2015-06-05 09:26:00.249187-03 | 205 2015-06-05 09:27:00.826874-03 | 207 2015-06-05 09:28:00.374666-03 | 73 2015-06-05 09:29:00.690696-03 | 75 Occurrence of the problem citgis=# select max(dvi_sub.dvi_cod_dados_via_iti) as dvi_cod_dados_via_iti, dvi_sub.via_cod_viagem from gis_dvi_dados_viagem_itinerario dvi_sub, gis_via_viagem via_sub, gis_iti_itinerario iti_sub where dvi_sub.via_cod_viagem = via_sub.via_cod_viagem and via_sub.via_status_viagem = 'A' and via_sub.via_dt_hora_ini now() - interval '9 hours' and iti_sub.lin_cod_linha = 389 and iti_sub.iti_sentido_itinerario = 'I' and iti_sub.iti_cod_itinerario_linha = via_sub.iti_cod_itinerario_linha and dvi_sub.vlo_cod_localizacao is not null group by dvi_sub.via_cod_viagem, iti_sub.iti_cod_itinerario_linha, via_sub.equ_cod_eqpto ; Cancel request sent ERROR: canceling statement due to user request Time: 2555.557 ms citgis=# select max(dvi_sub.dvi_cod_dados_via_iti) as dvi_cod_dados_via_iti, dvi_sub.via_cod_viagem from gis_dvi_dados_viagem_itinerario dvi_sub, gis_via_viagem via_sub, gis_iti_itinerario iti_sub where dvi_sub.via_cod_viagem = via_sub.via_cod_viagem and via_sub.via_status_viagem = 'A' and via_sub.via_dt_hora_ini now() - interval '9 hours' and iti_sub.lin_cod_linha = 389 and iti_sub.iti_sentido_itinerario = 'I' and iti_sub.iti_cod_itinerario_linha = via_sub.iti_cod_itinerario_linha and dvi_sub.vlo_cod_localizacao is not null group by dvi_sub.via_cod_viagem, iti_sub.iti_cod_itinerario_linha, via_sub.equ_cod_eqpto ; Cancel request sent ERROR: canceling statement due to user request Time: 2192.572 ms citgis=# explain analyze select max(dvi_sub.dvi_cod_dados_via_iti) as dvi_cod_dados_via_iti, dvi_sub.via_cod_viagem from gis_dvi_dados_viagem_itinerario dvi_sub, gis_via_viagem via_sub, gis_iti_itinerario iti_sub where dvi_sub.via_cod_viagem = via_sub.via_cod_viagem and via_sub.via_status_viagem = 'A' and via_sub.via_dt_hora_ini now() - interval '9 hours' and iti_sub.lin_cod_linha = 389 and iti_sub.iti_sentido_itinerario = 'I' and iti_sub.iti_cod_itinerario_linha = via_sub.iti_cod_itinerario_linha and dvi_sub.vlo_cod_localizacao is not null group by dvi_sub.via_cod_viagem, iti_sub.iti_cod_itinerario_linha, via_sub.equ_cod_eqpto ; Cancel request sent ERROR: canceling statement due to user request Time: 10164.015 ms citgis=# select now(); now --- 2015-06-05 09:27:22.006072-03 (1 row) Time: 0.152 ms citgis=# select max(dvi_sub.dvi_cod_dados_via_iti) as dvi_cod_dados_via_iti, dvi_sub.via_cod_viagem from gis_dvi_dados_viagem_itinerario dvi_sub, gis_via_viagem via_sub, gis_iti_itinerario iti_sub where dvi_sub.via_cod_viagem = via_sub.via_cod_viagem and via_sub.via_status_viagem = 'A' and via_sub.via_dt_hora_ini now() - interval '9 hours' and iti_sub.lin_cod_linha = 389 and iti_sub.iti_sentido_itinerario = 'I' and iti_sub.iti_cod_itinerario_linha = via_sub.iti_cod_itinerario_linha and dvi_sub.vlo_cod_localizacao is not null group by dvi_sub.via_cod_viagem, iti_sub.iti_cod_itinerario_linha, via_sub.equ_cod_eqpto ; dvi_cod_dados_via_iti |
Re: [GENERAL] Momentary Delay
2015-06-08 12:30 GMT-03:00 Adrian Klaver adrian.kla...@aklaver.com: On 06/08/2015 07:59 AM, Anderson Valadares wrote: Hi We are experiencing an intermittent problem in a GIS database from a client. Some times of the day is as if the PostgreSQL executed the slowest operations see below an example. The query was performed three times, twice I canceled and the third time I left it to end. The consultation took 10 seconds to finish, but the measured execution time is 20 ms. As we have several queries that run every 2 seconds when this momentary delay occurs queries accumulate and burst the limit of 203 connections allowed. The interval of momentary stop are approximately 2 seconds occurring at random times and during these stoppages occur no locks and no increased load on the server is identified. There is a job 2/2 seconds locks collection of information, running queries, etc., nmon also collects information every 2 seconds. I do not have an answer, but I do have a question. What does: There is a job 2/2 seconds locks collection of information, running queries, etc mean? My client asks what causes these momentary stops? because it affects all operations of the database? etc. How do I identify what is causing these delays in executions of operations in the database? The Server is a IBM P720 128G RAM PostgreSQL 9.2.9 on powerpc-ibm-aix7.1.0.0, compiled by gcc (GCC) 4.6.4, 64-bit Evolution of the number of connections for a period snap_datetime | #connections --+- 2015-06-05 09:25:00.954731-03 |74 2015-06-05 09:26:00.249187-03 |205 2015-06-05 09:27:00.826874-03 |207 2015-06-05 09:28:00.374666-03 |73 2015-06-05 09:29:00.690696-03 |75 Occurrence of the problem citgis=# select max(dvi_sub.dvi_cod_dados_via_iti) as dvi_cod_dados_via_iti, dvi_sub.via_cod_viagem from gis_dvi_dados_viagem_itinerario dvi_sub, gis_via_viagem via_sub, gis_iti_itinerario iti_sub where dvi_sub.via_cod_viagem = via_sub.via_cod_viagem and via_sub.via_status_viagem = 'A' and via_sub.via_dt_hora_ini now() - interval '9 hours' and iti_sub.lin_cod_linha = 389 and iti_sub.iti_sentido_itinerario = 'I' and iti_sub.iti_cod_itinerario_linha = via_sub.iti_cod_itinerario_linha and dvi_sub.vlo_cod_localizacao is not null group by dvi_sub.via_cod_viagem, iti_sub.iti_cod_itinerario_linha, via_sub.equ_cod_eqpto ; Cancel request sent ERROR: canceling statement due to user request Time: 2555.557 ms citgis=# select max(dvi_sub.dvi_cod_dados_via_iti) as dvi_cod_dados_via_iti, dvi_sub.via_cod_viagem from gis_dvi_dados_viagem_itinerario dvi_sub, gis_via_viagem via_sub, gis_iti_itinerario iti_sub where dvi_sub.via_cod_viagem = via_sub.via_cod_viagem and via_sub.via_status_viagem = 'A' and via_sub.via_dt_hora_ini now() - interval '9 hours' and iti_sub.lin_cod_linha = 389 and iti_sub.iti_sentido_itinerario = 'I' and iti_sub.iti_cod_itinerario_linha = via_sub.iti_cod_itinerario_linha and dvi_sub.vlo_cod_localizacao is not null group by dvi_sub.via_cod_viagem, iti_sub.iti_cod_itinerario_linha, via_sub.equ_cod_eqpto ; Cancel request sent ERROR: canceling statement due to user request Time: 2192.572 ms citgis=# explain analyze select max(dvi_sub.dvi_cod_dados_via_iti) as dvi_cod_dados_via_iti, dvi_sub.via_cod_viagem from gis_dvi_dados_viagem_itinerario dvi_sub, gis_via_viagem via_sub, gis_iti_itinerario iti_sub where dvi_sub.via_cod_viagem = via_sub.via_cod_viagem and via_sub.via_status_viagem = 'A' and via_sub.via_dt_hora_ini now() - interval '9 hours' and iti_sub.lin_cod_linha = 389 and iti_sub.iti_sentido_itinerario = 'I' and iti_sub.iti_cod_itinerario_linha = via_sub.iti_cod_itinerario_linha and dvi_sub.vlo_cod_localizacao is not null group by dvi_sub.via_cod_viagem, iti_sub.iti_cod_itinerario_linha, via_sub.equ_cod_eqpto ; Cancel request sent ERROR: canceling statement due to user request Time: 10164.015 ms citgis=# select now(); now --- 2015-06-05 09:27:22.006072-03 (1 row) Time: 0.152 ms citgis=# select max(dvi_sub.dvi_cod_dados_via_iti) as dvi_cod_dados_via_iti, dvi_sub.via_cod_viagem from gis_dvi_dados_viagem_itinerario dvi_sub, gis_via_viagem via_sub, gis_iti_itinerario iti_sub where dvi_sub.via_cod_viagem = via_sub.via_cod_viagem and via_sub.via_status_viagem = 'A' and via_sub.via_dt_hora_ini
