字段长度超过限制

[skymoou]

CREATE TABLE IF NOT EXISTS actiontech_udup.gtid_executed_v2 (
job_uuid binary(16) NOT NULL COMMENT 'unique identifier of job',
source_uuid binary(16) NOT NULL COMMENT 'uuid of the source where the transaction was originally executed.',
interval_gtid text NOT NULL COMMENT 'number of interval.'
);

当做全量同步的时候， interval_gtid 字段长度不够，直接导致job失败 报错信息：
2018/10/25 10:31:09.274531 [ERR] agent: Task "Dest" for alloc "589aa77c-db36-b485-b36d-42b8f3ff2a3d" failed: Wait returned exit code 2, and error Error 1406: Data too long for column 'interval_gtid' at row 1

[skymoou]

建议可以将字段长度适当修正，增加字段长度

Caused by discrete GTID GNO

123456789:123456791:123456793:123456795:123456797:123456799:123456801:123456803:123456805:123456807:123456809:123456811:123456813:123456815:123456817:123456819:123456821:123456823:123456825:123456827:123456829:123456831:123456833:123456835:123456837:123456839:123456841:123456843:123456845:123456847:123456849:123456851:123456853:123456855:123456857:123456859:123456861...

Two considerations

• text can hold 64KB.
  • while mediumtext: 16MB (256X larger); longtext: 4GB (256*256=65536X larger)
    • any performance drawback?
• Discrete gtid gno values make us cannot store it in intervals like a-b:c-d
  • (Use a better scheme to store the values)
  • complement the gap to make it continuous
    • introducing inconsistency?
  • store as binary / numerically instead of text
  • compressed storage

75a3d86

fix _ #342: Data too long for column 'interval_gtid' …

• use longtext (4GB) instead of text (64KB)
• migrate gtid_executed_v2 to gtid_executed_v3
• prevent task if future gtid_executed table present

TODO gtid_executed_v4

• compression
• binary storage

NB: migrating gtid_executed_v2 to gtid_executed_v3 is one-way.