Re: [HACKERS] Needs Suggestion
On Apr 20, 2011, at 4:08 AM, SUBHAM ROY wrote: > Suppose Postgres is installed in two computers C1 & C2. > C1 have some database tables. How can I copy these database tables from C1 to > C2. > I mean to say that can I copy tables from postgres installed in one m/c to > another m/c. > Is there any command in postgres to do so or any other short cut technique. Use pg_dump/pg_restore command to copy the tables from One database to another. http://www.postgresql.org/docs/9.0/interactive/backup-dump.html Thanks & Regards, Vibhor Kumar EnterpriseDB Corporation The Enterprise PostgreSQL Company vibhor.ku...@enterprisedb.com Blog:http://vibhork.blogspot.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
[HACKERS] Needs Suggestion
Suppose Postgres is installed in two computers C1 & C2. C1 have some database tables. How can I copy these database tables from C1 to C2. I mean to say that can I copy tables from postgres installed in one m/c to another m/c. Is there any command in postgres to do so or any other short cut technique. -- Thank You, Subham Roy, CSE IIT Bombay.
Re: [HACKERS] Needs Suggestion
SUBHAM ROY writes: > I want to know how can we measure the execution time of a query in Postgres > (Explain analyze will not do). Also is there any tools available in Linux > for measuring the performance of queries of databases such as Oracle 11g, > Postgres, etc. > Any suggestions will be very helpful. Try pgbench (in contribs) and then Tsung, that could help you run a test suite and get time reports. See also pgbench-tools. http://www.westnet.com/~gsmith/content/postgresql/pgbench-tools.htm Regards, -- Dimitri Fontaine http://2ndQuadrant.fr PostgreSQL : Expertise, Formation et Support -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
[HACKERS] Re: [HACKERS] Needs Suggestion
You could use this in psql. Don't know how precise is it, but is enought for initial testing. postgres=# \timing Timing is on. postgres=# create index dx on diplomka using gist(data); CREATE INDEX Time: 236752.569 ms > Původní zpráva > Od: SUBHAM ROY > Předmět: Re: [HACKERS] Needs Suggestion > Datum: 27.3.2011 19:02:32 > > Actually, I want to run some set of queries in postgres on a HUGE data set. > I have to compute the actual execution time for each of those queries. So > how can I do that in Postgres ? > > Suppose in Oracle following thing can be done : > * > set timing on; > select stuff from mytab; > > Elapsed: 00:00:02.82 > > *Likewise, can I do this in Postgres? "set timing on" does not work in > Postgres. > Also is there any free tools available in Linux for doing so? > > On Sun, Mar 27, 2011 at 10:20 PM, Gurjeet Singh > wrote: > > > On Sun, Mar 27, 2011 at 9:22 AM, SUBHAM ROY wrote: > > > >> Hi, > >> I am currently a student of IIT Bombay. I am doing a project on "Benchmark > >> design". For that I need to measure the performance of various queries in > >> databases. > >> I want to know how can we measure the execution time of a query in > >> Postgres (Explain analyze will not do). Also is there any tools available > >> in > >> Linux for measuring the performance of queries of databases such as Oracle > >> 11g, Postgres, etc. > >> Any suggestions will be very helpful. > >> > > > > If EXPLAIN ANALYZE is not sufficient for your purpose, then you need > > elaborate what exactly are you looking for. > > > > Regards, > > -- > > Gurjeet Singh > > EnterpriseDB Corporation > > The Enterprise PostgreSQL Company > > > > > > > -- > Thank You, > Subham Roy, > CSE IIT Bombay. > > > -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Needs Suggestion
In these (Postgres) mailing lists, top-posting is not preferred. See my response below. On Sun, Mar 27, 2011 at 1:01 PM, SUBHAM ROY wrote: > > On Sun, Mar 27, 2011 at 10:20 PM, Gurjeet Singh > wrote: > >> On Sun, Mar 27, 2011 at 9:22 AM, SUBHAM ROY wrote: >> >>> Hi, >>> I am currently a student of IIT Bombay. I am doing a project on >>> "Benchmark design". For that I need to measure the performance of various >>> queries in databases. >>> I want to know how can we measure the execution time of a query in >>> Postgres (Explain analyze will not do). Also is there any tools available in >>> Linux for measuring the performance of queries of databases such as Oracle >>> 11g, Postgres, etc. >>> Any suggestions will be very helpful. >>> >> >> If EXPLAIN ANALYZE is not sufficient for your purpose, then you need >> elaborate what exactly are you looking for. >> >> Actually, I want to run some set of queries in postgres on a HUGE data > set. > I have to compute the actual execution time for each of those queries. So > how can I do that in Postgres ? > > Suppose in Oracle following thing can be done : > * > set timing on; > select stuff from mytab; > > Elapsed: 00:00:02.82 > > *Likewise, can I do this in Postgres? "set timing on" does not work in > Postgres. > Also is there any free tools available in Linux for doing so? > Postgres' command-line clinet is psql, and it has a meta-command \timing (or \t for short) This will show you the query execution time, including the network roundtrip it takes to send the query and receive the response. If you don't want to account for network round trips, the the server has a GUC parameter called log_min_duration_statement [1]. Either you change it's value in postgresql.conf (so it affects all connections thereafter), or use SQL command set log_min_duration_statement = 0; as the first command in all your sessions to log all queries. psql's \t command results in times being shown right in the psql session, but setting log_min_duration_statement results in query and time taken beong logged in server logs (usually under $PGDATA/pg_log/ or in syslog). [1] http://www.postgresql.org/docs/current/static/runtime-config-logging.html#RUNTIME-CONFIG-LOGGING-WHEN HTH, -- Gurjeet Singh EnterpriseDB Corporation The Enterprise PostgreSQL Company
Re: [HACKERS] Needs Suggestion
Actually, I want to run some set of queries in postgres on a HUGE data set. I have to compute the actual execution time for each of those queries. So how can I do that in Postgres ? Suppose in Oracle following thing can be done : * set timing on; select stuff from mytab; Elapsed: 00:00:02.82 *Likewise, can I do this in Postgres? "set timing on" does not work in Postgres. Also is there any free tools available in Linux for doing so? On Sun, Mar 27, 2011 at 10:20 PM, Gurjeet Singh wrote: > On Sun, Mar 27, 2011 at 9:22 AM, SUBHAM ROY wrote: > >> Hi, >> I am currently a student of IIT Bombay. I am doing a project on "Benchmark >> design". For that I need to measure the performance of various queries in >> databases. >> I want to know how can we measure the execution time of a query in >> Postgres (Explain analyze will not do). Also is there any tools available in >> Linux for measuring the performance of queries of databases such as Oracle >> 11g, Postgres, etc. >> Any suggestions will be very helpful. >> > > If EXPLAIN ANALYZE is not sufficient for your purpose, then you need > elaborate what exactly are you looking for. > > Regards, > -- > Gurjeet Singh > EnterpriseDB Corporation > The Enterprise PostgreSQL Company > > -- Thank You, Subham Roy, CSE IIT Bombay.
Re: [HACKERS] Needs Suggestion
On Sun, Mar 27, 2011 at 9:22 AM, SUBHAM ROY wrote: > Hi, > I am currently a student of IIT Bombay. I am doing a project on "Benchmark > design". For that I need to measure the performance of various queries in > databases. > I want to know how can we measure the execution time of a query in Postgres > (Explain analyze will not do). Also is there any tools available in Linux > for measuring the performance of queries of databases such as Oracle 11g, > Postgres, etc. > Any suggestions will be very helpful. > If EXPLAIN ANALYZE is not sufficient for your purpose, then you need elaborate what exactly are you looking for. Regards, -- Gurjeet Singh EnterpriseDB Corporation The Enterprise PostgreSQL Company
Re: [HACKERS] Needs Suggestion
Subham, I would start with reviewing Prof Mike Stonebrakers and Dr Paula Hawthorns paper http://portal.acm.org/citation.cfm?doid=582095.582097 you can also look at Perftrack http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.101.7063&rep=rep1&type=pdf regards 3dmashUp On 3/27/2011 6:22 AM, SUBHAM ROY wrote: Hi, I am currently a student of IIT Bombay. I am doing a project on "Benchmark design". For that I need to measure the performance of various queries in databases. I want to know how can we measure the execution time of a query in Postgres (Explain analyze will not do). Also is there any tools available in Linux for measuring the performance of queries of databases such as Oracle 11g, Postgres, etc. Any suggestions will be very helpful. -- Thank You, Subham Roy, CSE IIT Bombay. -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
[HACKERS] Needs Suggestion
Hi, I am currently a student of IIT Bombay. I am doing a project on "Benchmark design". For that I need to measure the performance of various queries in databases. I want to know how can we measure the execution time of a query in Postgres (Explain analyze will not do). Also is there any tools available in Linux for measuring the performance of queries of databases such as Oracle 11g, Postgres, etc. Any suggestions will be very helpful. -- Thank You, Subham Roy, CSE IIT Bombay.
Re: [HACKERS] Needs Suggestion
On 09/22/2010 05:03 AM, sub...@cse.iitb.ac.in wrote: Actually, I used palloc() to set the stack base address. And I am trying to create only a single thread, then also it is causing problem. Did you not understand when people told you this wasn't going to work? Don't create any threads. cheers andrew -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Needs Suggestion
So, Can I increase the stack depth limit to a large value ? > On 22/09/10 12:03, sub...@cse.iitb.ac.in wrote: >> Actually, I used palloc() to set the stack base address. >> And I am trying to create only a single thread, then also it is causing >> problem. >> Actually, I created all the data-structures using palloc(), then I am >> passing these to the child thread. Even if I make these variables global >> then also it is not working. >> But if I don't set its stack address then it is working. But I need to >> do >> that because when my thread body is big then it is causing stack fault. >> So if I cannot set its stack address then Can I increase the stack depth >> limit to a large value ? > > It's not clear what you're trying to do, but it's just not going to > work. The backend code is not thread-safe, so you can't safely create > any threads in server code. Not even a single one. And even if you > could, you should not mess with stack base addresses. > > -- >Heikki Linnakangas >EnterpriseDB http://www.enterprisedb.com > -- Thank You, Subham Roy. -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Needs Suggestion
Actually, I used palloc() to set the stack base address. And I am trying to create only a single thread, then also it is causing problem. Actually, I created all the data-structures using palloc(), then I am passing these to the child thread. Even if I make these variables global then also it is not working. But if I don't set its stack address then it is working. But I need to do that because when my thread body is big then it is causing stack fault. So if I cannot set its stack address then Can I increase the stack depth limit to a large value ? -- Thank You, Subham Roy. > On 22/09/10 11:14, sub...@cse.iitb.ac.in wrote: >> >> How can I increase the stack depth limit ? Is it only by modifying the >> postgres.conf file, but there I cannot increase the stack depth beyond 4 >> MB. >> >> Actually, my problem is that, when I set the stack base address of the >> child thread using the POSIX library function "pthread_setstackaddr()", >> I >> am unable to access the memory contents of its parent. The >> data-structures >> in the parent are either getting destroyed or unaccessible when moving >> to >> the context of the child thread. > > It is not a good idea to use threads in server code. PostgreSQL server > code is not thread-safe, things will break. > > Assuming that you're not actually doing that but using threads in the > client instead, max_stack_depth should have no effect on you as it only > affects the server. > > But you really should find another way to communicate between threads. > Stacks should be treated as thread-private. Use malloc() or something > and global variables. > > -- >Heikki Linnakangas >EnterpriseDB http://www.enterprisedb.com > -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Needs Suggestion
sub...@cse.iitb.ac.in writes: > How can I increase the stack depth limit ? Is it only by modifying the > postgres.conf file, but there I cannot increase the stack depth beyond 4 > MB. > Actually, my problem is that, when I set the stack base address of the > child thread using the POSIX library function "pthread_setstackaddr()", I > am unable to access the memory contents of its parent. You've got worse problems than the stack depth limit. Creating multiple threads inside a backend process is entirely unsupported and just about guaranteed to result in massive breakage. Don't do it. regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Needs Suggestion
On 22/09/10 12:03, sub...@cse.iitb.ac.in wrote: Actually, I used palloc() to set the stack base address. And I am trying to create only a single thread, then also it is causing problem. Actually, I created all the data-structures using palloc(), then I am passing these to the child thread. Even if I make these variables global then also it is not working. But if I don't set its stack address then it is working. But I need to do that because when my thread body is big then it is causing stack fault. So if I cannot set its stack address then Can I increase the stack depth limit to a large value ? It's not clear what you're trying to do, but it's just not going to work. The backend code is not thread-safe, so you can't safely create any threads in server code. Not even a single one. And even if you could, you should not mess with stack base addresses. -- Heikki Linnakangas EnterpriseDB http://www.enterprisedb.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Needs Suggestion
On 22/09/10 11:14, sub...@cse.iitb.ac.in wrote: How can I increase the stack depth limit ? Is it only by modifying the postgres.conf file, but there I cannot increase the stack depth beyond 4 MB. Actually, my problem is that, when I set the stack base address of the child thread using the POSIX library function "pthread_setstackaddr()", I am unable to access the memory contents of its parent. The data-structures in the parent are either getting destroyed or unaccessible when moving to the context of the child thread. It is not a good idea to use threads in server code. PostgreSQL server code is not thread-safe, things will break. Assuming that you're not actually doing that but using threads in the client instead, max_stack_depth should have no effect on you as it only affects the server. But you really should find another way to communicate between threads. Stacks should be treated as thread-private. Use malloc() or something and global variables. -- Heikki Linnakangas EnterpriseDB http://www.enterprisedb.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
[HACKERS] Needs Suggestion
How can I increase the stack depth limit ? Is it only by modifying the postgres.conf file, but there I cannot increase the stack depth beyond 4 MB. Actually, my problem is that, when I set the stack base address of the child thread using the POSIX library function "pthread_setstackaddr()", I am unable to access the memory contents of its parent. The data-structures in the parent are either getting destroyed or unaccessible when moving to the context of the child thread. But when I create the child thread without setting its stack base address then it is able to access the parent's memory contents. But if the child thread's code size is large then it is getting stack fault and displaying the message "MAX stack depth limit reached ...". Can anyone give any reason why is that so ? OR If I cannot set the child thread's stack base address. Then How can I increase the stack depth limit to a large value ? -- Thank You, Subham Roy. -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Needs Suggestion
On Mon, Aug 30, 2010 at 11:12 AM, wrote: > Can anyone explain this ? > > My question is - > What is lnext:; , lreplace:; in postgres code ? > I found lnext:; in 1501 and lreplace:; in 2065 in execMain.c file. It's a label. http://www.lysator.liu.se/c/bwk-tutor.html#goto -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise Postgres Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
[HACKERS] Needs Suggestion
Can anyone explain this ? My question is - What is lnext:; , lreplace:; in postgres code ? I found lnext:; in 1501 and lreplace:; in 2065 in execMain.c file. -- Thank You, Subham Roy. CSE, IIT Bombay. -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Needs Suggestion
sub...@cse.iitb.ac.in writes: > I need suggestion about how region based memory management is done in > postgres. Have you read src/backend/utils/mmgr/README ? It's old but still reasonably accurate. regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
[HACKERS] Needs Suggestion
I need suggestion about how region based memory management is done in postgres. I know the concept of region based memory management and also know about the functions like memorycontextswitch(). But I am not understanding how Postgres uses hierarchical, region-based memory management. That is I am not getting the inner idea or meaning of the code. Currently, my project topic is "Parallelizing the spatial join" using POSIX threads, so I have to understand the inner details and meanings of the code. I am using "ddd" to step through its code, from there I am getting the flow of the code but not understanding the semantics of its data-structures and its region based memory management. Kindly, if anybody can give some Ideas or Suggestions. Thank You, Subham Roy, CSE, IIT Bombay. -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Needs Suggestion
On Sat, Jul 3, 2010 at 1:04 PM, wrote: > I am currently a student of IIT Bombay of CSE department. I am doing a > project on postgres. I need to understand its code thoroughly, so I need > "ddd" to "step through" its code. I need to start postgres on the > "backend" mode to work it with "ddd".But I am facing some difficulties in > setting up the "ddd" with "postgres" in "backend" mode. > > I installed postgres many times using the instruction mentioned in the > file "INSTALL". Starting the postgres from foreground is working fine but > the "backend" mode does not work. > > Kindly, suggest me how to run the postgres in "backend" mode. I have to > understand its code thoroughly to do my postgres project. If by "backend" mode you mean a standalone backend, try "postgres --single". If you mean something else... you'll need to explain a bit more. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise Postgres Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Needs Suggestion
sub...@cse.iitb.ac.in wrote: > > Hi, > > I am currently a student of IIT Bombay of CSE department. I am doing a > project on postgres. I need to understand its code thoroughly, so I need > "ddd" to "step through" its code. I need to start postgres on the > "backend" mode to work it with "ddd".But I am facing some difficulties in > setting up the "ddd" with "postgres" in "backend" mode. > > I installed postgres many times using the instruction mentioned in the > file "INSTALL". Starting the postgres from foreground is working fine but > the "backend" mode does not work. > > Kindly, suggest me how to run the postgres in "backend" mode. I have to > understand its code thoroughly to do my postgres project. I suggest you look here first: http://www.postgresql.org/developer/coding and at the developer's faq. -- Bruce Momjian http://momjian.us EnterpriseDB http://enterprisedb.com + None of us is going to be here forever. + -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
[HACKERS] Needs Suggestion
Hi, I am currently a student of IIT Bombay of CSE department. I am doing a project on postgres. I need to understand its code thoroughly, so I need "ddd" to "step through" its code. I need to start postgres on the "backend" mode to work it with "ddd".But I am facing some difficulties in setting up the "ddd" with "postgres" in "backend" mode. I installed postgres many times using the instruction mentioned in the file "INSTALL". Starting the postgres from foreground is working fine but the "backend" mode does not work. Kindly, suggest me how to run the postgres in "backend" mode. I have to understand its code thoroughly to do my postgres project. Thank You, Subham Roy, CSE, IIT Bombay. -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
