Improve processed records count calculatation at pipeline increment task.

[azexcy]

the merge method may merge INSERT and DELETE operations, so calculatate count before merge

Changes proposed in this pull request:

• Calculate processed records count before merged operation
• Improve mysql client reconnect

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• My code follows the code of conduct of this project.
• I have self-reviewed the commit code.
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[azexcy]

the ci process result

dataSourceName: ds_0
incremental:
  delay:
    lastEventTimestamps: 1665537963000
    latestActiveTimeMillis: 1665537966842
  position: binlog.000001#182842306
inventory:
  finished:
  - ds_0.t_order_copy#0
processedRecordsCount: 3015
sourceDatabaseType: MySQL
status: EXECUTE_INCREMENTAL_TASK

now the processedRecordsCount is correct when increment task is runing.