Olympia + Firebird + Mon$statements

Remoting SDK
1

Hi, we deploy a omplyia server using firebird 3.0 database and we notice some crashes (A lot of them)

the database is using all the memory in server, and we notice a very high increase in cpu usage too

The first thing we notice is the table mon$statments is keep getting bigger and bigger (maybe the transactions is not been commited?) - i was able to notice this when the server wasn`t very loaded, only 3 users and after a few minutes we get 200+ records in this table

Our .daConnections:

		<Definition>
			<Description/>
			<ConnectionString>FB4.NET?Server=IP;Database=IP:XXXXX;UserID=XXX;Password=XXXXXX</ConnectionString>
			<ConnectionType>Interbase</ConnectionType>
			<Default>True</Default>
			<Name>Olympia.FB.NET</Name>
		</Definition>

we also detected a large number of deadlock:
An exception was raised on the server: deadlock update conflicts with concurrent update concurrent transaction number is 4785765
Inner Exception: IscException: deadlock update conflicts with concurrent update concurrent transaction number is 4785765

we can’t get the transaction, beacause if we try to select anyting from the mon$ tables in firebird the server will crash, cause the very high load on the machine

and the last error just before the server crash:

An exception was raised on the server: too many open handles to database
Inner Exception: IscException: too many open handles to database

again, we cant even select anything from mon$attachments without crashing the server

here is the json

{
  "ServiceName": "PServerSession",
  "Port": 3090,
  "EventTimeout": 180,
  "SessionTimeout": 1800,
  "PoolSize": 1,
  "InMemoryMode": false 
}

we have something like 100 users ±, and 150-200 sessions

before olympia we used a regular sessionmanager in memory (Delphi 10.3)

2

Hi,

Looks like you have caught this issue - Memory leak in Firebird 3 on implicit transaction [DNET743] · Issue #685 · FirebirdSQL/NETProvider · GitHub

as a workarounds, you can try to

  • install the latest versions of Firebird and NETProvider. also use PoolSize = 4 here:

or

  • back to Firebird 2.5
3

Looks fixed in firebird 3.0.3

4

the last .net driver is 9.0.2 dosent seems to work using olympia, do you know wich version i can update?

5

Hi,

Can you retest this issue with the latest Firebird versions, i.e. Firebird 3.0.10, Firebird 4.0.2 and Firebird 2.5.9, pls?

6

I will test using firebird 3.0.10

Can’t test using 2.5 or 4.0+

I will let you know the results

(couldn’t update the ado.net Olympia just crash when I try the last one)

7

Tested using firebird 3.0.10
.net driver version 7.0

same results, at the moment MON$STATEMENTS has 193.404 records

mix of

        DELETE
        FROM
        "EVENTUSERDATA"
        WHERE
        ("EVENTUSER" = ?) AND
        ("EVENTID" = ?)

UPDATE “SESSION”
SET
“LASTACCESSED” = ?,
“DATA” = ?
WHERE
(“ID” = ?)

        INSERT
        INTO "EVENTUSERDATA"
        ("EVENTUSER", "EVENTID")
        VALUES
        (?, ?)

still getting this before crash

An exception was raised on the server: too many open handles to database

and random

An exception was raised on the server: deadlock
update conflicts with concurrent update
concurrent transaction number is 2185594
Inner Exception: IscException: deadlock
update conflicts with concurrent update

8

hello, help! whelp!

9

Hi,

This is issue with NETProvider.
They have closed that bug as not a bug/wontfix so it still be reproduced in FB 3.0

10

Ok, but what can i do ? there is a way to upgrade de .net drivers for olympia?

11

and, they said is cause because this Issues · FirebirdSQL/firebird · GitHub
and that one is fixed

12

Hi,

as for me, in [FB3] Memory Leaks. FB does not release memory after load tests. [CORE5416] they have fixed leaks after load tests.

if you still reproduce issue in FB 3.0.10 so they did incomplete fix and issue is still persist.

I can suggest to try to test this issue with Firebird 2.5.

by other hand, you can try to use 3rd party providers like ODBC Driver for Firebird 32/64-bit - Devart - they may work more stable

13

Ok, im now using sqlite, is stable, not so fast but stable.

there is any chance to upgrade .net drivers for olympia in the future? i notice is using version 7.0.0

the last version is 9.2

i will test using PG too, but fb is easier for me

14

Logged as bugs://D19290.

17

bugs://D19290 was closed as fixed.