How to get previous log file
Hi! select pg_read_file(pg_current_logfile()) retrieves today log file. Log files are in log directory: /var/lib/postgresql/12/main/log# ls ... postgresql-2020-06-08_00.log postgresql-2020-06-18_00.log postgresql-2020-06-28_00.log postgresql-2020-06-09_00.log postgresql-2020-06-19_00.log How get yesterday log file from remote client application using postgresql query ? Using Postgres 12 in Debian. Andrus.
Re: How to get previous log file
On 6/28/20 2:42 AM, Andrus wrote: Hi! select pg_read_file(pg_current_logfile()) retrieves today log file. Log files are in log directory: /var/lib/postgresql/12/main/log# ls ... postgresql-2020-06-08_00.log postgresql-2020-06-18_00.log postgresql-2020-06-28_00.log postgresql-2020-06-09_00.log postgresql-2020-06-19_00.log How get yesterday log file from remote client application using postgresql query ? Using Postgres 12 in Debian. You where half way there: https://www.postgresql.org/docs/12/functions-admin.html pg_ls_dir() -- To get file names. pg_read_file() -- Using file name from above. Andrus. -- Adrian Klaver adrian.kla...@aklaver.com
Re: n_distinct off by a factor of 1000
On 2020-06-24 16:27:35 -0600, Michael Lewis wrote: > On Wed, Jun 24, 2020, 2:35 PM Peter J. Holzer wrote: > > Yes, estimating the number of distinct values from a relatively small > sample is hard when you don't know the underlying distribution. It might > be possible to analyze the sample to find the distribution and get a > better estimate. But I'm not sure how useful that would really be: If > a few values are very common and most very rare you are probably also > much more likely to use the common values in a query: And for those you > you would massively underestimate their frequency if you had an accurate > n_distinct value. That might be just as bad or even worse. > > > > This would only be true for values that are "common" but not in the MCVs list, > right? Yes, but if you have 33 million values there are likely to be a lot of them "common but not in the MCVs list", even for a very biased distribution. > If we could increase the sampling ratio beyond the hard coded 300x to get a > more representative sample I thought of that but abandoned it since I don't think a better estimate for n_distinct will help (see above for the reason). The problem is that the distribution is biased and the planner has no idea whether the value it is searching for is common or rare if it isn't in the MCV list. Unless ... As I understood Klaudie, the values are ids, and ids have no inherent meaning, the common values are probably scattered randomly. But it might be possible to change that. Group the ids by frequency. Ids < 1E12 occur at most 10 times, Ids >= 1E12 <2E12 occur at most 100 times and so on. This may mean that ids aren't long time stable - they may change as their frequency changes. But if an id always changes by a multiple of 1E12, the last 12 decimal digits are stable. The advantage is that then the planner can use the histogram to get a pretty good estimate of how frequent a value is. hp -- _ | Peter J. Holzer| Story must make more sense than reality. |_|_) || | | | h...@hjp.at |-- Charles Stross, "Creative writing __/ | http://www.hjp.at/ | challenge!" signature.asc Description: PGP signature
Fwd: BUG #16513: Postgresql HA Cluster
Hi Team, Please help us on the below query . Thanks -- Forwarded message - From: Daniel Gustafsson Date: Sat, 27 Jun, 2020, 3:16 AM Subject: Re: BUG #16513: Postgresql HA Cluster To: , PostgreSQL mailing lists < pgsql-b...@lists.postgresql.org> > On 26 Jun 2020, at 16:10, PG Bug reporting form wrote: > Is there any functionality present in postgresql for HA availability where > we can setup multiple nodes/instances in READ-WRITE mode for single database > so that incase of one node/instance failure we can use the 2nd one without > failure or in less time ,this is just like oracle RAC concept . This mailinglist is for bugreports against the PostgreSQL server, which the above isn't. Please see the -general mailinglist for general questions. More information on how to subscribe can be found at: https://www.postgresql.org/list/ cheers ./daniel
Postgresql HA Cluster
Hi All, Is there any functionality present in postgresql for High Availability Cluster where we can setup multiple nodes/instances in READ-WRITE mode for single database so that incase of one node/instance failure it will automatically failover the traffic to 2nd node/instance (without failure or in less time) ,this is just like oracle RAC concept . Here High Availability Cluster means there will be zero downtime incase of any one node/instance failure. Please help us to know this. Thanks & Regards, Brajendra
bdr_init_copy ends fine but doesn't copy the remote db
I am trying to make a multi-master replication using BDR and because of the DDL issues-errors, I decided to use bdr_init_copy command instead of using bdr.bdr_group_join(). I have two servers with PostgreSQL services and one of them(Master2) has an empty DB, the other(Master1) has one schema and one table on its DB. When I try to run bdr_init_copy command, everything goes well and the last rows of the output are these: . Initializing BDR on the local node: bdrdemo: adding the database to BDR cluster ...All done But when I check, the schema and the table on the Master1 is not copied to Master2. Master2's database is still empty. What could have gone wrong? The bdr_init_copy that I used is: ./bdr_init_copy -D /var/lib/pgsql/9.4-bdr/data -n node2 -d 'host=10.m1.m1.m1 port=5598 dbname=bdrdemo' -U postgres --local-dbname='host=10.m2.m2.m2 port=5598 dbname=bdrdemo'
