Mysql Java Connector Ubuntu
Angie Troia
It looks from other questions (askubuntu, stackoverflow) that it was contained in libmysql-java (which is no longer there), and then moved to libmariadb-java (weird because as far as I know, it's different database - but I found sort of confirmation on debian package description).
MariaDB Connector/J is a Type 4 JDBC driver. It was developed specifically asa lightweight JDBC connector for use with MariaDB and MySQL database servers.It was originally based on the Drizzle JDBC code with numerous additions andbug fixes.
The following subsections show the formatting of JDBC connection strings forMariaDB and MySQL database servers. Additionally, sample code is provided thatdemonstrates how to connect to one of these servers and create a table.
The preferred way to get a connection with MariaDB Connector/J is to use the DriverManager class.When the DriverManager class is used to locate and load MariaDB Connector/J, the application needs no further configuration. The DriverManager class will automatically load MariaDB Connector/J and allow it to be used in the same way as any other JDBC driver.
MariaDB Connector/J 3.0 only accepts jdbc:mariadb: as the protocol in connection strings by default. When both MariaDB Connector/J and the MySQL drivers are found in the class-path, using jdbc:mariadb: as the protocol helps to ensure that Java chooses MariaDB Connector/J.
driver 3.0 is a complete rewrite of the connector. Specific support for aurora has not been implemented in 3.0, since it relies on pipelining. Aurora is not compatible with pipelining.Issues for Aurora were piling up without the community proposing any PR for them and without access for us to test those modifications. (2.x version has a 5 years support).
GSSAPI in windows isn't well supported in java, causing recurrent issues. Since 3.1, waffle-jna is marked as a dependency to provide good GSSAPI support without problems. This has the drawback to make connector and dependencies to a size of around 4Mb.
By default, the connector adopts the JVM's default time zone. If the client and server reside in different time zones, it's recommended to configure the connection time zone to match the JVM's default by setting forceConnectionTimeZoneToSession to true.This ensures proper operation of time functions.
Due to its wider range, DATETIME is sometimes mistakenly used to store a specific point in time. While this might work if the client and server share the same time zone, it creates problems when they differ.
While using DATETIME instead of TIMESTAMP is generally discouraged, a specific combination of settings ("preserveInstants=true&connectionTimeZone=SERVER") can force all Java Timestamp exchanges to be converted to the connection's time zone during storage and retrieval. However, this approach is not recommended for long-term solutions.
The MariaDB Connector/J versions before 3.4 offered a single "timezone" option. While this functionality remains compatible, it's now separated into two distinct settings: connectionTimeZone and forceConnectionTimeZoneToSession. Here's a breakdown of how the old option translates to the new ones:"timezone=America/Los_Angeles" is equivalent to "connectionTimeZone=America/Los_Angeles&forceConnectionTimeZone=true
The fastest way to load lots of data is using LOAD DATA INFILE.
However, using "LOAD DATA LOCAL INFILE" (ie: loading a file from the client) may be a security problem if someone can execute a query from the client, he can have access to any file on the client (according to the rights of the user running the client process).
To avoid using too much memory, rather use Statement.setFetchSize(int numberOfRowInMemory) to indicate the number of rows that will be stored in memory
Example :
using Statement.setFetchSize(1000) indicates that 1000 rows will be stored in memory.
So, when the query has executed, 1000 rows will be in memory. After 1000 ResultSet.next(), the next 1000 rows will be stored in memory, and so on.
If another query is run on same connection while the resultset has not been completly read, the connector will fetch all remaining rows before executing the query. This can lead to still needing lots of memory. Recommendation is then to use another connection for simultaneous operations.
Note that the server usually expects clients to read off the result set relatively quickly. The net_write_timeout server variable controls this behavior (defaults to 60s).If you don't expect results to be handled in this amount of time there is a different possibility:
If another query is executed on the same connection when a streaming resultset has not been fully read, the connector will put the whole remaining streaming resultset in memory in order to execute the next query. This can lead to OutOfMemoryError if not handled.
Before version 1.4.0, the only accepted value for fetch size was Statement.setFetchSize(Integer.MIN_VALUE) (equivalent to Statement.setFetchSize(1)). This value is still accepted for compatilibity reasons but rather use Statement.setFetchSize(1), since according to JDBC the value must be >= 0.
The driver uses server prepared statements as a standard to communicate with the database (since 1.3.0). If the "allowMultiQueries" options are set to true, the driver will only use text protocol. Prepared statements (parameter substitution) is handled by the driver, on the client side.
To use this credential authentication, com.amazonaws:aws-java-sdk-rds dependency must be registred in classpath.Implementation use SDK DefaultAWSCredentialsProviderChain and DefaultAwsRegionProviderChain to get IAM credential and region.see DefaultAWSCredentialsProviderChain and DefaultAwsRegionProviderChain to check how those information can be retrieved (environment variable / system properties, files, ...)
New authentication plugins can be created implementing interface org.mariadb.jdbc.authentication.AuthenticationPlugin, and listing new plugin in a META-INF/services/org.mariadb.jdbc.authentication.AuthenticationPlugin file.
Custom SSL implementation can be used implementing A connection to a server initially creates a socket. When set, SSL socket is layered over this existing socket. Implementing org.mariadb.jdbc.tls.TlsSocketPlugin permit to provide custom SSL implementation for example create a new HostnameVerifier implementation.
Most of the time this will be caused by reading a query that has a large resultset; the server usually expects clients to read off the result set relatively quickly. The net_write_timeout server variable controls this behavior (defaults to 60s). If the client doesn't read the whole resultset in that amount of time, the server will discard the connection.If you don't expect results to be handled in this amount of time there is another possibility:
Connection.isValid() is a good approach. Connection.isValid() is doing a ping (ping in mysql protocol, not network ping). Connection pool using JDBC4 Validation are using automatically this Connection.isValid()
I've installed a stock mysql 5.5 installation, and while I can connect to the mysql service via the mysql command, and the service seems to be running, I cannot connect to it through spring+tomcat or from an external jdbc connector.
1) Verify the address mysql is bound to, it's probably 127.0.0.1 (only) which I believe is the default (at least on standard Ubuntu server). You'll have to comment out the bind-addressparameter in my.cnf to bind to all available addresses (you can't choose multiple, it's one or all).
I spend some days to solve this problem. I have tested many approaches that have been mentioned in different web sites, but non of them worked. Finally I changed my code and found out what was the problem. I'll try to tell you about different approaches and sum them up here.
While I was seeking the internet to find the solution for this error, I figured out that there are many solutions that worked for at least one person, but others say that it doesn't work for them! why there are many approaches to this error?It seems this error can occur generally when there is a problem in connecting to the server. Maybe the problem is because of the wrong query string or too many connections to the database.
But what solved my problem?My problem was that I had many SELECTs on database. Each time I created connection and then closed it. Although I closed the connection every time, but the system faced with many connections and gave me that error. What I did was that I defined my connection variable as a public (or private) variable for whole class and initialized it in the constructor. Then every time I just used that connection. It solved my problem and also increased my speed dramatically.
There is no simple and unique way to solve this problem. I suggest you to think about your own situation and choose above solutions. If you take this error at the beginning of the program and you are not able to connect to the database at all, you might have problem in your connection string. But If you take this error after several successful interaction to the database, the problem might be with number of connections and you may think about changing "wait_timeout" and other MySQL settings or rewrite your code how that reduce number of connections.
This can also be caused by wrong proxy settings.I had this problem trying to connect via jdbc to a MySQL instance running in a Parallels virtual appliance on my Mac.The jdbc connection uses the system-level network settings and since I was behind a SOCKS proxy I had to set the MySql host as a non-proxy host (e.g., on a Mac you can configure that in Settings->Network->Advanced->Proxies, and finally add the hostname or IP address in the "Bypass proxy settings for these Hosts and Domains").
i had a very similar problem for almost a day, and it drove me crazy! but i managed to found the solution, and it was very, very simple, you just need to /etc/init.d/tomcat6 to change TOMCAT6_SECURITY=yes to TOMCAT6_SECURITY=no.it's not my solution, i found it here, as you can see, i am running ubuntu, hope this works.
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