[HACKERS] Burst in WAL size when UUID is used as PK while full_page_writes are enabled
Hi, I was reading the blog https://blog.2ndquadrant.com/on-the-impact-of-full-page-writes . My queries: How randomness of UUID will likely to create new leaf page in btree index? In my understanding as the size of UUID is 128 bits i.e. twice of BIGSERIAL , more number of pages will be required to store the same number of rows and hence there can be increase in WAL size due to FPW . When compared the index size in local setup UUID index is ~2x greater in size. Thanks, Sanyam Jain
[HACKERS] Start logical decoding from any lsn present in the wal segment
Hi, Currently logical decoding finds a consistent point by generating a snapshot and stream changes after consistent point.I want to change this behaviour to something which stream changes from a lsn in the past provided its present in wal segment.Can this behaviour be implemented and if yes, what are the steps i should perform to implement the same. Thanks, Sanyam Jain
Re: [HACKERS] pgjdbc logical replication client throwing exception
Hi, I suspect its happening because of delay in status update by client but even after trying forceUpdateStatus its quitting prematurely. Thanks, Sanyam Jain From: sanyam jain Sent: Tuesday, June 27, 2017 6:47:55 AM To: Peter Eisentraut; Pg Hackers Subject: Re: [HACKERS] pgjdbc logical replication client throwing exception Hi, >What does the server log say? If nothing interesting, turn up debugging. I receive the following Log on server LOG: could not send data to client: Broken pipe Thanks, Sanyam Jain
Re: [HACKERS] pgjdbc logical replication client throwing exception
Hi, >What does the server log say? If nothing interesting, turn up debugging. I receive the following Log on server LOG: could not send data to client: Broken pipe Thanks, Sanyam Jain
Re: [HACKERS] Logical decoding on standby
Hi, >After changing >sendTimeLineIsHistoric = state->currTLI == ThisTimeLineID; >to >sendTimeLineIsHistoric = state->currTLI != ThisTimeLineID; > >I was facing another issue. >On promotion of a cascaded server ThisTimeLineID in the standby server having >>logical slot becomes 0. >Then i added a function call to GetStandbyFlushRecPtr in >StartLogicalReplication >which updates ThisTimeLineID. > >After the above two changes timeline following is working.But i'm not sure >whether >this is correct or not.In any case please someone clarify. Please anyone with experience can explain whether the steps i have done are correct or not. Thanks, Sanyam Jain
[HACKERS] pgjdbc logical replication client throwing exception
Hi, I'm trying to create something like pg_recvlogical.c in java using pgjdbc.Its working for small transactions but when i do a big transaction client throws below exception: org.postgresql.util.PSQLException: Database connection failed when reading from copy at org.postgresql.core.v3.QueryExecutorImpl.readFromCopy(QueryExecutorImpl.java:1028) at org.postgresql.core.v3.CopyDualImpl.readFromCopy(CopyDualImpl.java:41) at org.postgresql.core.v3.replication.V3PGReplicationStream.receiveNextData(V3PGReplicationStream.java:150) at org.postgresql.core.v3.replication.V3PGReplicationStream.readInternal(V3PGReplicationStream.java:119) at org.postgresql.core.v3.replication.V3PGReplicationStream.readPending(V3PGReplicationStream.java:73) at XLogApplier.main(XLogApplier.java:63) Caused by: java.net.SocketException: Socket closed at java.net.SocketInputStream.socketRead0(Native Method) at java.net.SocketInputStream.read(SocketInputStream.java:152) at java.net.SocketInputStream.read(SocketInputStream.java:122) at org.postgresql.core.VisibleBufferedInputStream.readMore(VisibleBufferedInputStream.java:140) at org.postgresql.core.VisibleBufferedInputStream.ensureBytes(VisibleBufferedInputStream.java:109) at org.postgresql.core.VisibleBufferedInputStream.read(VisibleBufferedInputStream.java:191) at org.postgresql.core.PGStream.receive(PGStream.java:495) at org.postgresql.core.PGStream.receive(PGStream.java:479) at org.postgresql.core.v3.QueryExecutorImpl.processCopyResults(QueryExecutorImpl.java:1161) at org.postgresql.core.v3.QueryExecutorImpl.readFromCopy(QueryExecutorImpl.java:1026) ... 5 more PG Server reports a broken pipe. Can someone please tell what can be wrong?Its happening only when i add millions of rows. Thanks, Sanyam Jain
Re: [HACKERS] Logical decoding on standby
Hi, After changing sendTimeLineIsHistoric = state->currTLI == ThisTimeLineID; to sendTimeLineIsHistoric = state->currTLI != ThisTimeLineID; I was facing another issue. On promotion of a cascaded server ThisTimeLineID in the standby server having logical slot becomes 0. Then i added a function call to GetStandbyFlushRecPtr in StartLogicalReplication which updates ThisTimeLineID. After the above two changes timeline following is working.But i'm not sure whether this is correct or not.In any case please someone clarify. Thanks, Sanyam Jain
Re: [HACKERS] Logical decoding on standby
Hi, In this patch in walsender.c sendTimeLineIsHistoric is set to true when current and ThisTimeLineID are equal. sendTimeLineIsHistoric = state->currTLI == ThisTimeLineID; Shouldn't sendTimeLineIsHistoric is true when state->currTLI is less than ThisTimeLineID. When i applied the timeline following patch alone pg_recvlogical quits in startup phase but when i made the above change pg_recvlogical works although timeline following doesn't work. Thanks, Sanyam Jain From: pgsql-hackers-ow...@postgresql.org on behalf of Robert Haas Sent: Wednesday, April 5, 2017 3:25:50 PM To: Andres Freund Cc: Craig Ringer; Simon Riggs; Thom Brown; Michael Paquier; Petr Jelinek; PostgreSQL Hackers Subject: Re: [HACKERS] Logical decoding on standby On Wed, Apr 5, 2017 at 10:32 AM, Andres Freund wrote: > On 2017-04-05 17:18:24 +0800, Craig Ringer wrote: >> On 5 April 2017 at 04:19, Andres Freund wrote: >> > On 2017-04-04 22:32:40 +0800, Craig Ringer wrote: >> >> I'm much happier with this. I'm still fixing some issues in the tests >> >> for 03 and tidying them up, but 03 should allow 01 and 02 to be >> >> reviewed in their proper context now. >> > >> > To me this very clearly is too late for v10, and now should be moved to >> > the next CF. >> >> I tend to agree that it's late in the piece. It's still worth cleaning >> it up into a state ready for early pg11 though. > > Totally agreed. Based on this exchange, marked as "Moved to next CF". -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL 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] Why forcing Hot_standby_feedback to be enabled when creating a logical decoding slot on standby
Isn't XLogRecord carries full information to be decoded in itself?If so a VACCUM should not be a problem in decoding? Thanks Sanyam Jain From: Michael Paquier Sent: Monday, June 12, 2017 6:52:06 AM To: sanyam jain Cc: Pg Hackers Subject: Re: [HACKERS] Why forcing Hot_standby_feedback to be enabled when creating a logical decoding slot on standby On Mon, Jun 12, 2017 at 3:16 PM, sanyam jain wrote: > I have created a logical decoding slot on a standby but i haven't enabled > Hot_standby_feedback.What are the test cases where this setup will fail? hot_standby_feedback needs to be enabled at all times in logical decoding so as the node does not remove rows that are still needed for the decoding, and a VACUUM passing by with a minimal xmin too high would cause inconsistent decoded data. -- Michael
[HACKERS] Why forcing Hot_standby_feedback to be enabled when creating a logical decoding slot on standby
Hi, I have created a logical decoding slot on a standby but i haven't enabled Hot_standby_feedback.What are the test cases where this setup will fail? Thanks, Sanyam Jain
[HACKERS] Use of snapshot in logical replication
Hi, Can someone explain the usage of exporting snapshot when a logical replication slot is created? Thanks, Sanyam Jain
