JDBC: pooled connection not seeing new row
The problem here is easy to reproduce:
1) First a request creates a row. The front-end receives the row-ID.
2) Then another request is sent to read the row's data using the ID (like 200 ms
later).
3) There is no such row!!!
The architecture is for a high-throughput financial exchange. Many many orders per second need to be inserted into the DB. The implementation is in Java 8.
Each request-thread owns an open connection, inside a wrapper that stores some cached PreparedStatements as well. All specific for the application, that is why we're not using a regular pool.
All connections are kept in the transaction mode (autocommit=false) as 90% of the requests will end executing a transaction. Autocommit remains FALSE forever after creating the connection. "Selects" also use this connection.
Then each use of the connection uses the regular 'commit()' or 'rollback()' in the end. Selects do not call them. Only updates or inserts.
For the problem I'm seeing:
I found a "fix" that is to call 'commit()' or 'rollback()' before using the connection. By doing this, the data visible to the connection seems to be refreshed and it works fine. By the way, the tx-level is the default for Amazon Aurora MySQL, REPEATABLE_READ.
I have seen the existence of beginRequest() and endRequest() methods but their documentation got me a little bit confused.
My question is: is this the expected behaviour? What's the most performant approach to handle this? How to indicate to a connection that we want it to see refreshed data from DB?
Thanks
mysql jdbc aws-aurora auto-commit
asked 2 mins ago
Ernani SottomaiorErnani Sottomaior
1
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The problem here is easy to reproduce:
1) First a request creates a row. The front-end receives the row-ID.
2) Then another request is sent to read the row's data using the ID (like 200 ms
later).
3) There is no such row!!!
The architecture is for a high-throughput financial exchange. Many many orders per second need to be inserted into the DB. The implementation is in Java 8.
Each request-thread owns an open connection, inside a wrapper that stores some cached PreparedStatements as well. All specific for the application, that is why we're not using a regular pool.
All connections are kept in the transaction mode (autocommit=false) as 90% of the requests will end executing a transaction. Autocommit remains FALSE forever after creating the connection. "Selects" also use this connection.
Then each use of the connection uses the regular 'commit()' or 'rollback()' in the end. Selects do not call them. Only updates or inserts.
For the problem I'm seeing:
I found a "fix" that is to call 'commit()' or 'rollback()' before using the connection. By doing this, the data visible to the connection seems to be refreshed and it works fine. By the way, the tx-level is the default for Amazon Aurora MySQL, REPEATABLE_READ.
I have seen the existence of beginRequest() and endRequest() methods but their documentation got me a little bit confused.
My question is: is this the expected behaviour? What's the most performant approach to handle this? How to indicate to a connection that we want it to see refreshed data from DB?
Thanks
mysql jdbc aws-aurora auto-commit
asked 2 mins ago
Ernani SottomaiorErnani Sottomaior
1
New contributor
Ernani Sottomaior is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |
The problem here is easy to reproduce:
1) First a request creates a row. The front-end receives the row-ID.
2) Then another request is sent to read the row's data using the ID (like 200 ms
later).
3) There is no such row!!!
The architecture is for a high-throughput financial exchange. Many many orders per second need to be inserted into the DB. The implementation is in Java 8.
Each request-thread owns an open connection, inside a wrapper that stores some cached PreparedStatements as well. All specific for the application, that is why we're not using a regular pool.
All connections are kept in the transaction mode (autocommit=false) as 90% of the requests will end executing a transaction. Autocommit remains FALSE forever after creating the connection. "Selects" also use this connection.
Then each use of the connection uses the regular 'commit()' or 'rollback()' in the end. Selects do not call them. Only updates or inserts.
For the problem I'm seeing:
I found a "fix" that is to call 'commit()' or 'rollback()' before using the connection. By doing this, the data visible to the connection seems to be refreshed and it works fine. By the way, the tx-level is the default for Amazon Aurora MySQL, REPEATABLE_READ.
I have seen the existence of beginRequest() and endRequest() methods but their documentation got me a little bit confused.
My question is: is this the expected behaviour? What's the most performant approach to handle this? How to indicate to a connection that we want it to see refreshed data from DB?
Thanks
mysql jdbc aws-aurora auto-commit
asked 2 mins ago
Ernani SottomaiorErnani Sottomaior
1
New contributor
Ernani Sottomaior is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
The problem here is easy to reproduce:
1) First a request creates a row. The front-end receives the row-ID.
2) Then another request is sent to read the row's data using the ID (like 200 ms
later).
3) There is no such row!!!
The architecture is for a high-throughput financial exchange. Many many orders per second need to be inserted into the DB. The implementation is in Java 8.
Each request-thread owns an open connection, inside a wrapper that stores some cached PreparedStatements as well. All specific for the application, that is why we're not using a regular pool.
All connections are kept in the transaction mode (autocommit=false) as 90% of the requests will end executing a transaction. Autocommit remains FALSE forever after creating the connection. "Selects" also use this connection.
Then each use of the connection uses the regular 'commit()' or 'rollback()' in the end. Selects do not call them. Only updates or inserts.
For the problem I'm seeing:
I found a "fix" that is to call 'commit()' or 'rollback()' before using the connection. By doing this, the data visible to the connection seems to be refreshed and it works fine. By the way, the tx-level is the default for Amazon Aurora MySQL, REPEATABLE_READ.
I have seen the existence of beginRequest() and endRequest() methods but their documentation got me a little bit confused.
My question is: is this the expected behaviour? What's the most performant approach to handle this? How to indicate to a connection that we want it to see refreshed data from DB?
Thanks
mysql jdbc aws-aurora auto-commit
mysql jdbc aws-aurora auto-commit
asked 2 mins ago
Ernani SottomaiorErnani Sottomaior
1
New contributor
Ernani Sottomaior is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 2 mins ago
Ernani SottomaiorErnani Sottomaior
1
New contributor
Ernani Sottomaior is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 2 mins ago
Ernani SottomaiorErnani Sottomaior
1
New contributor
Ernani Sottomaior is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 2 mins ago
Ernani SottomaiorErnani Sottomaior
1
asked 2 mins ago
Ernani SottomaiorErnani Sottomaior
1
1
New contributor
Ernani Sottomaior is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
Ernani Sottomaior is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Ernani Sottomaior is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
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