[Enhancement]: Add dynamic configuration for lower_case_table_names i… by SimonChou12138 · Pull Request #156 · oceanbase/seekdb

SimonChou12138 · 2026-02-05T03:30:20Z

Task Description

Fix hardcoded table names in SQL queries to support lower_case_table_names system variable. This resolves issues where system tables cannot be found when lower_case_table_names=0 (case-sensitive mode) is configured.

Related to case-sensitivity handling for MySQL compatibility.

Solution Description

Replace hardcoded table names with constants: Changed direct string literals like __all_server and __all_zone to use constants from ob_inner_table_schema_constants.h (e.g., OB_ALL_SERVER_TNAME, OB_ALL_ZONE_TNAME)
Read lower_case_table_names from system variables: Modified bootstrap and schema initialization code to dynamically read the lower_case_table_names setting instead of hardcoding OB_LOWERCASE_AND_INSENSITIVE
Support environment variable configuration: Added support for setting lower_case_table_names via the LOWER_CASE_TABLE_NAMES environment variable in main.cpp
Set proper name_case_mode for system tables: Ensured system tables always use case-sensitive mode (OB_ORIGIN_AND_SENSITIVE) regardless of tenant settings, while user tables respect the tenant's lower_case_table_names configuration

Modified files:

src/observer/main.cpp
src/rootserver/ob_bootstrap.cpp
src/share/ob_locality_table_operator.cpp
src/share/schema/ob_schema_mgr.cpp
src/share/schema/ob_schema_utils.cpp
src/share/schema/ob_server_schema_service.cpp
src/storage/tx/wrs/ob_tenant_weak_read_cluster_service.cpp

Passed Regressions

Manually tested with lower_case_table_names=0 configuration
Verified system tables are accessible with case-sensitive mode
Confirmed bootstrap process completes successfully
Tested SQL queries against system tables work correctly
After making the modifications, I rebuilt and mirrored the image for running. Then, I added an environment variable to the Docker configuration to pull up the container. After verifying the settings and querying the configuration, I found that the parameter was effective

Upgrade Compatibility

This change is backward compatible:

Default behavior remains unchanged (defaults to lower_case_table_names=1)
Existing deployments will continue to work without modification
New configuration option is opt-in via environment variable or command-line parameter

Other Information

This fix improves MySQL compatibility by properly supporting the lower_case_table_names system variable, which is important for:

Cross-platform deployments (Linux/macOS/Windows)
Migration from MySQL databases with case-sensitive table names
Compliance with MySQL standard behavior

Release Note

Enhancement: Added proper support for lower_case_table_names system variable. System table names are now referenced using constants instead of hardcoded strings, enabling case-sensitive table name mode (lower_case_table_names=0) to work correctly. This improves MySQL compatibility and supports cross-platform deployments.

…nstead of hard coding

CLAassistant · 2026-02-05T03:30:27Z

All committers have signed the CLA.

Copilot

Pull request overview

This PR aims to make table-name handling compatible with MySQL lower_case_table_names, removing hardcoded inner-table names and making name-case mode configurable during bootstrap/initialization (including via an environment variable).

Changes:

Replace hardcoded inner-table names in SQL strings with ob_inner_table_schema_constants.h constants.
Read lower_case_table_names dynamically from system-variable defaults during bootstrap/schema initialization (instead of hardcoding).
Allow setting lower_case_table_names via LOWER_CASE_TABLE_NAMES environment variable during process startup.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
src/observer/main.cpp	Reads `LOWER_CASE_TABLE_NAMES` env var and injects `lower_case_table_names` into startup variables if not provided on cmdline.
src/rootserver/ob_bootstrap.cpp	Uses `SYS_VAR_LOWER_CASE_TABLE_NAMES` to set `arg.name_case_mode_` for sys-tenant creation.
src/share/ob_locality_table_operator.cpp	Replaces `__all_server` / `__all_zone` literals with constants in a join query.
src/share/schema/ob_schema_mgr.cpp	Changes how `name_case_mode` is applied when adding table schemas, with special handling for system tables.
src/share/schema/ob_schema_utils.cpp	Sets `name_case_mode` during inner-table schema construction based on `lower_case_table_names`.
src/share/schema/ob_server_schema_service.cpp	Initializes basic tenant sys-variable schema using `lower_case_table_names` default value.
src/storage/tx/wrs/ob_tenant_weak_read_cluster_service.cpp	Replaces `__all_server` literal with `OB_ALL_SERVER_TNAME` in a SQL string.

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Copilot · 2026-02-10T06:11:33Z

src/share/schema/ob_schema_utils.cpp

+  // Get name_case_mode from system variable BEFORE creating tables
+  ObNameCaseMode name_case_mode = OB_LOWERCASE_AND_INSENSITIVE; // default
+  if (OB_SUCC(ret) && construct_all) {
+    int64_t var_idx = ObSysVarsToIdxMap::get_store_idx(SYS_VAR_LOWER_CASE_TABLE_NAMES);
+    ObString lower_case_value = ObSysVariables::get_value(var_idx);
+


This new code uses ObSysVarsToIdxMap and ObSysVariables, but this .cpp file doesn't include the header that declares them (e.g., share/system_variable/ob_system_variable.h). Relying on transitive includes is brittle and can break builds if include order changes; please add the required include(s) in this file.

Okay, I'll put it at the beginning. Even though it can run without it after the image is built and pulled up

Copilot · 2026-02-10T06:11:33Z

src/share/schema/ob_schema_utils.cpp

@@ -652,21 +677,26 @@ int ObSchemaUtils::construct_inner_table_schemas(
        } else if (!construct_all && is_sys_tenant(tenant_id)
            && table_schema.get_table_id() == OB_ALL_CORE_TABLE_TID) {
          // sys tenant's __all_core_table's schema is built separately in bootstrap
-        } else if (OB_FAIL(ObSchemaUtils::construct_tenant_space_full_table(
-                tenant_id, table_schema))) {
-          LOG_WARN("fail to construct tenant space table", KR(ret), K(tenant_id));
-        } else if (OB_FAIL(ObSysTableChecker::is_inner_table_exist(
-                tenant_id, table_schema, exist))) {
-          LOG_WARN("fail to check inner table exist",
-              KR(ret), K(tenant_id), K(table_schema));
-        } else if (!construct_all && !exist) {
-          // skip
-        } else if (OB_FAIL(tables.push_back(table_schema))) {
-          LOG_WARN("fail to push back table schema", KR(ret), K(table_schema));
-        } else if (OB_FAIL(ObSysTableChecker::append_sys_table_index_schemas(
-                tenant_id, table_schema.get_table_id(), tables))) {
-          LOG_WARN("fail to append sys table index schemas",
-              KR(ret), K(tenant_id), "table_id", table_schema.get_table_id());
+        } else {
+          // Set name_case_mode for system tables
+          table_schema.set_name_case_mode(name_case_mode);
+


construct_inner_table_schemas() only reads SYS_VAR_LOWER_CASE_TABLE_NAMES when construct_all==true, but most call sites use the default (construct_all==false) when creating tenant inner tables. That means name_case_mode is forced to the hardcoded default (OB_LOWERCASE_AND_INSENSITIVE) in those paths, so lower_case_table_names=0 won't actually be honored during tenant schema construction.

You're right.

Copilot · 2026-02-10T06:11:34Z

src/share/schema/ob_schema_utils.cpp

+    if (OB_SUCC(ret) && construct_all) {
+      for (int64_t i = 0; i < tables.count(); ++i) {
+        ObTableSchema &table = tables.at(i);
+        table.set_name_case_mode(name_case_mode);


This sets name_case_mode for inner/system tables based on lower_case_table_names (and then applies it to all generated index/lob schemas too). That conflicts with the stated requirement (and the comment in ObSchemaMgr::add_table) that system tables should always use OB_ORIGIN_AND_SENSITIVE; with the current ObSchemaMgr logic preserving pre-set values, system tables can end up non-sensitive. Consider forcing OB_ORIGIN_AND_SENSITIVE here for inner tables, or ensure ObSchemaMgr overrides system tables unconditionally.

Suggested change

table.set_name_case_mode(name_case_mode);

// System/inner tables must always use OB_ORIGIN_AND_SENSITIVE, regardless of lower_case_table_names.

if (table.is_inner_table() || table.is_sys_table()) {

table.set_name_case_mode(OB_ORIGIN_AND_SENSITIVE);

} else {

table.set_name_case_mode(name_case_mode);

}

You're right.

Copilot · 2026-02-10T06:11:34Z

src/share/schema/ob_schema_mgr.cpp

+    // System tables ALWAYS use case-sensitive mode (OB_ORIGIN_AND_SENSITIVE = 0)
+    // regardless of tenant's lower_case_table_names setting
+    if (is_system_table) {
+      if (new_table_schema->get_name_case_mode() == OB_NAME_CASE_INVALID) {
+        // System table arrived with invalid mode - set it to case-sensitive
+        new_table_schema->set_name_case_mode(OB_ORIGIN_AND_SENSITIVE);
+      }
+      // Otherwise preserve the mode already set
+    } else {
+      // For user tables, use tenant's name_case_mode
+      new_table_schema->set_name_case_mode(mode);
+    }


The comment says system tables ALWAYS use OB_ORIGIN_AND_SENSITIVE, but the implementation only sets it when the incoming schema's name_case_mode is invalid; otherwise it preserves whatever was set upstream. Since upstream code can now set inner tables to a non-sensitive mode, this can violate the intended invariant. If system tables must always be case-sensitive, set OB_ORIGIN_AND_SENSITIVE unconditionally for is_system_table.

You're right.

Copilot · 2026-02-10T06:11:34Z

src/observer/main.cpp

+    if (!has_lower_case_in_cmdline) {
+      const char *env_value = getenv("LOWER_CASE_TABLE_NAMES");
+      if (nullptr != env_value && strlen(env_value) > 0) {
+        ObString key("lower_case_table_names");
+        ObString value(env_value);
+        if (OB_FAIL(opts.variables_.push_back(std::make_pair(key, value)))) {


parse_args() now uses getenv() and strlen(), but this file doesn't include /<stdlib.h> (for getenv) or /<string.h> (for strlen) on non-macOS builds. Please include the proper headers to avoid relying on transitive includes and to keep compilation portable.

You are right, input verification is indeed necessary

…standardization

SimonChou12138 · 2026-02-25T01:44:27Z

@hnwyllmm Hello, could you please help review it

[Enhancement]: Add dynamic configuration for lower_case_table_names i…

b4fa0d5

…nstead of hard coding

SimonChou12138 mentioned this pull request Feb 5, 2026

[Enhancement]: Add dynamic configuration for lower_case_table_names instead of hard coding #155

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hnwyllmm requested a review from Copilot February 10, 2026 06:05

Copilot started reviewing on behalf of hnwyllmm February 10, 2026 06:05 View session

Copilot AI reviewed Feb 10, 2026

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SimonChou12138 and others added 2 commits February 14, 2026 09:43

[Enhancement]: lower_case_table_names configuration and system table …

d04d135

…standardization

Merge branch 'oceanbase:develop' into develop

95c9295

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Task Description

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Upgrade Compatibility

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SimonChou12138 commented Feb 25, 2026

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