Re: [HACKERS] pgjdbc logical replication client throwing exception

[Dipesh Dangol]

Hi Andres,

I also checked server log. Nothing unusual is recorded there.
Do  you have any other suggestion. Thank you.

Best regards,
Dipesh Dangol

On Fri, Sep 15, 2017 at 11:32 PM, Dipesh Dangol 
wrote:

> Hi Vladimir,
> Ya, initially I was trying with withStatusInterval(20, TimeUnit.SECONDS),
> that didn't work so, then only I switched to  .withStatusInterval(20,
> TimeUnit.MILLISECONDS)
> but it is not working as well. I am not aware of type of test cases that
> you are pointing.
> Could you please send me any link for that one.
>
> For generating the load, I am using benchmarkSQL, which will generate
> around 9000
> transactions per second. I am trying to run streamAPI at the same time
> BenchmarskSQL is generating load. If i don't run benchmarkSQL it works
> fine I mean
> when there are only few transactions to replicate at a time, it works
> fine. But when
> I run it with that benchmarskSql and try to add some logic like some
> conditions, then
> it breaks down in between, most of the time within few seconds.
>
> Hi Andres,
> I haven't check the server log yet. Now, I don't access to my working
> environment, I will be able to check that only on Monday. If I find any
> suspicious
> thing in log, I will let you know.
>
> Thank you guys.
>
>
>
>
>
>
>
> On Fri, Sep 15, 2017 at 10:05 PM, Andres Freund 
> wrote:
>
>> On 2017-09-15 20:00:34 +, Vladimir Sitnikov wrote:
>> > ++pgjdbc dev list.
>> >
>> > >I am facing unusual connection breakdown problem. Here is the simple
>> code
>> > that I am using to read WAL file:
>> >
>> > Does it always fails?
>> > Can you create a test case? For instance, if you file a pull request
>> with
>> > the test, it will get automatically tested across various PG versions,
>> so
>> > it would be easier to reson about
>> >
>> > Have you tried "withStatusInterval(20, TimeUnit.SECONDS)" instead of 20
>> > millis? I don't think it matter much, however 20ms seems to be an
>> overkill.
>>
>> Also, have you checked the server log?
>>
>> - Andres
>>
>
>

Re: [HACKERS] pgjdbc logical replication client throwing exception

[Dipesh Dangol]

Hi Vladimir,
Ya, initially I was trying with withStatusInterval(20, TimeUnit.SECONDS),
that didn't work so, then only I switched to  .withStatusInterval(20,
TimeUnit.MILLISECONDS)
but it is not working as well. I am not aware of type of test cases that
you are pointing.
Could you please send me any link for that one.

For generating the load, I am using benchmarkSQL, which will generate
around 9000
transactions per second. I am trying to run streamAPI at the same time
BenchmarskSQL is generating load. If i don't run benchmarkSQL it works fine
I mean
when there are only few transactions to replicate at a time, it works fine.
But when
I run it with that benchmarskSql and try to add some logic like some
conditions, then
it breaks down in between, most of the time within few seconds.

Hi Andres,
I haven't check the server log yet. Now, I don't access to my working
environment, I will be able to check that only on Monday. If I find any
suspicious
thing in log, I will let you know.

Thank you guys.







On Fri, Sep 15, 2017 at 10:05 PM, Andres Freund  wrote:

> On 2017-09-15 20:00:34 +, Vladimir Sitnikov wrote:
> > ++pgjdbc dev list.
> >
> > >I am facing unusual connection breakdown problem. Here is the simple
> code
> > that I am using to read WAL file:
> >
> > Does it always fails?
> > Can you create a test case? For instance, if you file a pull request with
> > the test, it will get automatically tested across various PG versions, so
> > it would be easier to reson about
> >
> > Have you tried "withStatusInterval(20, TimeUnit.SECONDS)" instead of 20
> > millis? I don't think it matter much, however 20ms seems to be an
> overkill.
>
> Also, have you checked the server log?
>
> - Andres
>

Re: [HACKERS] pgjdbc logical replication client throwing exception

[Andres Freund]

On 2017-09-15 20:00:34 +, Vladimir Sitnikov wrote:
> ++pgjdbc dev list.
> 
> >I am facing unusual connection breakdown problem. Here is the simple code
> that I am using to read WAL file:
> 
> Does it always fails?
> Can you create a test case? For instance, if you file a pull request with
> the test, it will get automatically tested across various PG versions, so
> it would be easier to reson about
> 
> Have you tried "withStatusInterval(20, TimeUnit.SECONDS)" instead of 20
> millis? I don't think it matter much, however 20ms seems to be an overkill.

Also, have you checked the server log?

- Andres


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Re: [HACKERS] pgjdbc logical replication client throwing exception

[Vladimir Sitnikov]

++pgjdbc dev list.

>I am facing unusual connection breakdown problem. Here is the simple code
that I am using to read WAL file:

Does it always fails?
Can you create a test case? For instance, if you file a pull request with
the test, it will get automatically tested across various PG versions, so
it would be easier to reson about

Have you tried "withStatusInterval(20, TimeUnit.SECONDS)" instead of 20
millis? I don't think it matter much, however 20ms seems to be an overkill.

Vladimir

пт, 15 сент. 2017 г. в 19:57, Dipesh Dangol :

> hi,
>
> I am trying to implement logical replication stream API of postgresql.
> I am facing unusual connection breakdown problem. Here is the simple code
> that I am
> using to read WAL file:
>
> String url = "jdbc:postgresql://pcnode2:5432/benchmarksql";
> Properties props = new Properties();
> PGProperty.USER.set(props, "benchmarksql");
> PGProperty.PASSWORD.set(props, "benchmarksql");
> PGProperty.ASSUME_MIN_SERVER_VERSION.set(props, "9.4");
> PGProperty.REPLICATION.set(props, "database");
> PGProperty.PREFER_QUERY_MODE.set(props, "simple");
>
> Connection conn = DriverManager.getConnection(url, props);
> PGConnection replConnection = conn.unwrap(PGConnection.class);
>
> PGReplicationStream stream = replConnection.getReplicationAPI()
> .replicationStream().logical()
> .withSlotName("replication_slot3")
> .withSlotOption("include-xids", true)
> .withSlotOption("include-timestamp", "on")
> .withSlotOption("skip-empty-xacts", true)
> .withStatusInterval(20, TimeUnit.MILLISECONDS).start();
> while (true) {
>
> ByteBuffer msg = stream.read();
>
> if (msg == null) {
> TimeUnit.MILLISECONDS.sleep(10L);
> continue;
> }
>
> int offset = msg.arrayOffset();
> byte[] source = msg.array();
> int length = source.length - offset;
> String data = new String(source, offset, length);
>* System.out.println(data);*
>
> stream.setAppliedLSN(stream.getLastReceiveLSN());
> stream.setFlushedLSN(stream.getLastReceiveLSN());
>
> }
>
> Even the slightest modification in the code like commenting
> *System.out.println(data)*;
> which is just printing the data in the console, causes connection
> breakdown problem with
> following error msg
>
> 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:155)
> at
> org.postgresql.core.v3.replication.V3PGReplicationStream.readInternal(V3PGReplicationStream.java:124)
> at
> org.postgresql.core.v3.replication.V3PGReplicationStream.read(V3PGReplicationStream.java:70)
> at Server.main(Server.java:52)
> Caused by: java.net.SocketException: Socket closed
> at java.net.SocketInputStream.socketRead0(Native Method)
> at java.net.SocketInputStream.socketRead(SocketInputStream.java:116)
> at java.net.SocketInputStream.read(SocketInputStream.java:171)
> at java.net.SocketInputStream.read(SocketInputStream.java:141)
> 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
>
> I am trying to implement some logic like filtering out the unrelated table
> after reading log.
> But due to this unusual behavior I couldn't implement properly.
> Can somebody give me some hint how to solve this problem.
>
> Thank you.
>

[HACKERS] pgjdbc logical replication client throwing exception

[Dipesh Dangol]

hi,

I am trying to implement logical replication stream API of postgresql.
I am facing unusual connection breakdown problem. Here is the simple code
that I am
using to read WAL file:

String url = "jdbc:postgresql://pcnode2:5432/benchmarksql";
Properties props = new Properties();
PGProperty.USER.set(props, "benchmarksql");
PGProperty.PASSWORD.set(props, "benchmarksql");
PGProperty.ASSUME_MIN_SERVER_VERSION.set(props, "9.4");
PGProperty.REPLICATION.set(props, "database");
PGProperty.PREFER_QUERY_MODE.set(props, "simple");

Connection conn = DriverManager.getConnection(url, props);
PGConnection replConnection = conn.unwrap(PGConnection.class);

PGReplicationStream stream = replConnection.getReplicationAPI()
.replicationStream().logical()
.withSlotName("replication_slot3")
.withSlotOption("include-xids", true)
.withSlotOption("include-timestamp", "on")
.withSlotOption("skip-empty-xacts", true)
.withStatusInterval(20, TimeUnit.MILLISECONDS).start();
while (true) {

ByteBuffer msg = stream.read();

if (msg == null) {
TimeUnit.MILLISECONDS.sleep(10L);
continue;
}

int offset = msg.arrayOffset();
byte[] source = msg.array();
int length = source.length - offset;
String data = new String(source, offset, length);
   * System.out.println(data);*

stream.setAppliedLSN(stream.getLastReceiveLSN());
stream.setFlushedLSN(stream.getLastReceiveLSN());

}

Even the slightest modification in the code like commenting
*System.out.println(data)*;
which is just printing the data in the console, causes connection breakdown
problem with
following error msg

org.postgresql.util.PSQLException: Database connection failed when reading
from copy
at org.postgresql.core.v3.QueryExecutorImpl.readFromCopy(QueryE
xecutorImpl.java:1028)
at org.postgresql.core.v3.CopyDualImpl.readFromCopy(CopyDualImp
l.java:41)
at org.postgresql.core.v3.replication.V3PGReplicationStream.rec
eiveNextData(V3PGReplicationStream.java:155)
at org.postgresql.core.v3.replication.V3PGReplicationStream.rea
dInternal(V3PGReplicationStream.java:124)
at org.postgresql.core.v3.replication.V3PGReplicationStream.
read(V3PGReplicationStream.java:70)
at Server.main(Server.java:52)
Caused by: java.net.SocketException: Socket closed
at java.net.SocketInputStream.socketRead0(Native Method)
at java.net.SocketInputStream.socketRead(SocketInputStream.java:116)
at java.net.SocketInputStream.read(SocketInputStream.java:171)
at java.net.SocketInputStream.read(SocketInputStream.java:141)
at org.postgresql.core.VisibleBufferedInputStream.readMore(Visi
bleBufferedInputStream.java:140)
at org.postgresql.core.VisibleBufferedInputStream.ensureBytes(V
isibleBufferedInputStream.java:109)
at org.postgresql.core.VisibleBufferedInputStream.read(VisibleB
ufferedInputStream.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(QueryE
xecutorImpl.java:1026)
... 5 more

I am trying to implement some logic like filtering out the unrelated table
after reading log.
But due to this unusual behavior I couldn't implement properly.
Can somebody give me some hint how to solve this problem.

Thank you.

Re: [HACKERS] pgjdbc logical replication client throwing exception

[dipesh]

Hi,

I am also facing the same issue. Have you solved the problem?
Could you please guide me how to deal with it.

Thanks,
Dipesh



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Re: [HACKERS] pgjdbc logical replication client throwing exception

[sanyam jain]

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 <sanyamjai...@live.in>
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

[sanyam jain]

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

[Peter Eisentraut]

On 6/23/17 06:11, sanyam jain wrote:
> 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:

What does the server log say?  If nothing interesting, turn up debugging.

-- 
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PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services


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[HACKERS] pgjdbc logical replication client throwing exception

[sanyam jain]

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