CREATE VECTOR INDEX with drop_ratio_search fails with error 1210 for sparse vectors using SINDI/VSAG

Environment

• Version: Server version: 5.7.25 OceanBase seekdb (r) (Built 1-6006e21fa93bdfcf5496d13de61fe94aacaebaa4 Apr 6 2026)
• Platform: arm64
• Device: emulator-5554 (Android Studio Android Virtual Device)
• Startup Command: ./data/local/tmp/seekdb --nodaemon --base-dir /data/local/tmp/seekdb_data --port 5881
• Port: 5881

Description

When creating a vector index on a SPARSEVECTOR column using the SINDI type and VSAG library with the drop_ratio_search parameter specified, the operation fails with error 1210. The same operation succeeds when drop_ratio_search is not specified.

Steps to Reproduce

1. On the machine, navigate to the directory /obdata/data/AndroidTest/ob_opensource_test/tools/deploy.
2. Execute the following commands to set up the test environment and run the specific test case:

export OCEANBASE_HOME=/obdata/data/AndroidTest/ob_opensource_test/
cd ${OCEANBASE_HOME}/tools/deploy
source activate_obd.sh
export OBD_SEEKDB_STATUS_FALLBACK_TCP=1

obd test mysqltest test_env --mysqltest-bin=${OCEANBASE_HOME}/deps/3rd/u01/obclient/bin/mysqltest --obclient-bin=${OCEANBASE_HOME}/deps/3rd/u01/obclient/bin/obclient --init-only --init-sql-dir=${OCEANBASE_HOME}/tools/deploy --init-sql-files='init.sql,init_user.sql|root@sys|test'
obd test mysqltest test_env --mysqltest-bin=${OCEANBASE_HOME}/deps/3rd/u01/obclient/bin/mysqltest --obclient-bin=${OCEANBASE_HOME}/deps/3rd/u01/obclient/bin/obclient --disable-reboot --test-set=vector_index.sparse_vector_rebuild_refresh_index

3. Alternatively, execute the following SQL to reproduce the issue directly:

USE test;

-- The following segment is consistent with the use case; if the cluster has not enabled vectorized memory, you can first execute:
-- ALTER SYSTEM SET ob_vector_memory_limit_percentage = 20;

DROP TABLE IF EXISTS t1;

CREATE TABLE t1 (c1 INT, c2 SPARSEVECTOR);
INSERT INTO t1 VALUES (1, '{1:0.1,2:0.2, 3:0.3}');
INSERT INTO t1 VALUES (2, '{3:0.3, 2:0.2, 4:0.4}');

-- [FAILURE] Expected to succeed, but actual error 1210
CREATE VECTOR INDEX idx1 ON t1(c2)
  WITH (lib=vsag, type=sindi, distance=inner_product, drop_ratio_search=0.1);

-- [CONTROL] Usually succeeds without drop_ratio_search
DROP TABLE IF EXISTS t1;
CREATE TABLE t1 (c1 INT, c2 SPARSEVECTOR);
INSERT INTO t1 VALUES (1, '{1:0.1,2:0.2, 3:0.3}');
CREATE VECTOR INDEX idx2 ON t1(c2)
  WITH (lib=vsag, type=sindi, distance=inner_product);

Actual Result

The CREATE VECTOR INDEX statement with drop_ratio_search specified fails with error 1210.

Impact

This bug prevents users from creating sparse vector indexes with the drop_ratio_search parameter, which is a valid configuration for optimizing search performance.

Start by running vector_index.sparse_vector_rebuild_refresh_index or the direct SQL reproduction for CREATE VECTOR INDEX with SINDI, VSAG, and drop_ratio_search. Trace the error 1210 path for sparse-vector index creation and compare it with the successful case without that parameter. Done means the parameterized index is created successfully and the regression test passes.