Reducing JDBC SchemaDiscovery error timeout

[VardhanThigle]

Reducing MySQL SchemaDiscovery error timeout #1899

Overview

1. The default Backoff used in sourcedb-to-spanner for MySQL connections was quite large than Dataflow's pipeline launch failure.
2. Irrespective of the outer backoff, at the layer of jdbc connection pool, dbcp2 has an indefinite wait to acquire connections.

Fix

1. Added loginTimeout for jdbc (this takes into fact that dbcp2 does not natively support loginTimeOut. In the most Ideal case this can be implemented at the layer of JdbcDataSource too, but, it get's tricky to limit this to only discovery layer and also tricker to unit test)
2. The current loginTimout is limited only for discovery, as we have not faced this issue in runtime and capping run-time timeout could have un-intended side effects needed a thorough scale test. If the connectivity is not correctly configured we will any ways fail fast in the discovery layer.
3. Added stringificaiton of JdbcDataSource for better logging.
4. Minor logging typo fixes.

Sample Error logs

Log-1

com.google.cloud.teleport.v2.source.reader.io.jdbc.dialectadapter.mysql.MysqlDialectAdapter - Sql exception while discovering table list for datasource=JdbcDataSource: {"sourceDbURL":"jdbc:mysql://X.X.X.X:3306/test?allowMultiQueries=true&autoReconnect=true&maxReconnects=10", "initSql":"[SET TIME_ZONE = '+00:00', SET SESSION NET_WRITE_TIMEOUT=1200, SET SESSION NET_READ_TIMEOUT=1200]", "maxConnections","160" } cause=java.sql.SQLException: Cannot create PoolableConnectionFactory (Could not create connection to database server. Attempted reconnect 10 times. Giving up.)

Log-2

com.google.cloud.teleport.v2.source.reader.io.exception.SchemaDiscoveryException: java.sql.SQLException: Cannot create PoolableConnectionFactory (Could not create connection to database server. Attempted reconnect 10 times. Giving up.)
	at com.google.cloud.teleport.v2.source.reader.io.jdbc.dialectadapter.mysql.MysqlDialectAdapter.discoverTables(MysqlDialectAdapter.java:157)
	at com.google.cloud.teleport.v2.source.reader.io.schema.SchemaDiscoveryImpl.lambda$discoverTables$0(SchemaDiscoveryImpl.java:64)
	at com.google.cloud.teleport.v2.source.reader.io.schema.SchemaDiscoveryImpl.doRetries(SchemaDiscoveryImpl.java:114)
	at com.google.cloud.teleport.v2.source.reader.io.schema.SchemaDiscoveryImpl.discoverTables(SchemaDiscoveryImpl.java:63)
	at com.google.cloud.teleport.v2.source.reader.io.jdbc.iowrapper.JdbcIoWrapper.autoInferTableConfigs(JdbcIoWrapper.java:259)
	at com.google.cloud.teleport.v2.source.reader.io.jdbc.iowrapper.JdbcIoWrapper.of(JdbcIoWrapper.java:90)
	at com.google.cloud.teleport.v2.templates.PipelineController.executeSingleInstanceMigration(PipelineController.java:120)
	at com.google.cloud.teleport.v2.templates.SourceDbToSpanner.run(SourceDbToSpanner.java:111)
	at com.google.cloud.teleport.v2.templates.SourceDbToSpanner.main(SourceDbToSpanner.java:88)

Note

Note that Log-1 provides the host details as well as the exception, and is more relevant for debugging the connectivity issues than Log-2.

[codecov]

Codecov Report

Attention: Patch coverage is 93.93939% with 2 lines in your changes missing coverage. Please review.

Project coverage is 51.54%. Comparing base (0ac9251) to head (609d14a).
Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
...source/reader/io/jdbc/iowrapper/JdbcIoWrapper.java	90.90%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #1899      +/-   ##
============================================
+ Coverage     44.60%   51.54%   +6.93%     
+ Complexity     3549     1278    -2271     
============================================
  Files           832      370     -462     
  Lines         49282    20155   -29127     
  Branches       5184     2043    -3141     
============================================
- Hits          21983    10389   -11594     
+ Misses        25654     9108   -16546     
+ Partials       1645      658     -987     

Components	Coverage Δ
spanner-templates	66.24% <93.93%> (+0.86%)	⬆️
spanner-import-export	∅ <ø> (∅)
spanner-live-forward-migration	74.80% <ø> (ø)
spanner-live-reverse-replication	75.50% <ø> (ø)
spanner-bulk-migration	84.32% <93.93%> (+0.04%)	⬆️

Files with missing lines	Coverage Δ
...jdbc/dialectadapter/mysql/MysqlDialectAdapter.java	99.63% <ø> (ø)
...ctadapter/postgresql/PostgreSQLDialectAdapter.java	87.15% <ø> (ø)
...ource/reader/io/jdbc/iowrapper/JdbcDataSource.java	88.09% <100.00%> (+0.29%)	⬆️
.../io/jdbc/iowrapper/config/JdbcIOWrapperConfig.java	100.00% <100.00%> (ø)
...iowrapper/config/defaults/MySqlConfigDefaults.java	100.00% <100.00%> (ø)
...pper/config/defaults/PostgreSQLConfigDefaults.java	100.00% <100.00%> (ø)
...source/reader/io/jdbc/iowrapper/JdbcIoWrapper.java	93.56% <90.90%> (-0.40%)	⬇️

... and 479 files with indirect coverage changes

[bharadwaj-aditya]

LGTM Overall. Just a minor question.