【seekdb】【向量索引】【errcode=-7604】 serialize index failed

[Version information] (required)

It is recommended to post the results of bin/observer -V. If this test also involves obproxy version changes, it is also recommended to post the results of obproxy -V

：https://work.oceanbase-dev.com/automerge/iteration-branch-map

[Is it a temporary version provided by RD]

No/xxx temporarily provided

【Difficulty of recurrence】

Must appear/occasionally/uncertain/other

[Test changes]

Added xx test scenarios/changed to new machines/newly ran xx tools/replaced with new versions

[Are there any other abnormalities or changes in the environment?]

No / The clog disk has been full / it has been done manually. . /Injected xx exception

[Scenario description/reproduction steps (try to upload the reproduction sql as an attachment)] (required)

Reproduction scenario: Continue to execute ddl operation

Error report: [errcode=-7604] [Vsag](Log=BufferStreamReader: The file size is smaller than the memory you want to read.)

web connection:http://:22057/obdata/data/vec/ddl_duomo/obm.z1.obs0/

Log information:

Start by reproducing the failure while continuing DDL operations and correlate errcode -7604 with the logged paths in ob_trans_service_v4.cpp, ob_tx_table_interface.cpp, ob_tablet_create_delete_helper.cpp, and ob_tablet.cpp. Trace the vector-index serialization failure from the log message, then verify that repeated DDL no longer produces the truncated-read error and add or run the relevant regression coverage if the affected test entry point is found.