SQL Monitor (SQLM) and SQL Performance Tuning Worklist (SWLT)
SQL Monitor (SQLM) records aggregated Open SQL usage and runtime statistics over a monitoring period with source-position context, making it useful for finding SQL that is expensive because of frequency as well as single-call cost. The SQL Performance Tuning Worklist (SWLT) combines runtime/usage information with static checks such as ATC findings to prioritize custom-code SQL remediation by real production relevance.
Practical reference for SQL Monitor (SQLM) and SQL Performance Tuning Worklist (SWLT), including how the mechanism works, when it is appropriate, where it fits in SAP runtime/architecture, a realistic example, decision guidance, failure patterns, S/4HANA direction and operational ownership.
Reviewed by an ERPClimb SAP consultant on 20 Sept 2026· 775 words
What it is
A focused ST05 trace is excellent for one reproduction but cannot easily answer which custom SQL statements matter across days of productive usage. SQL Monitor collects aggregated statistics for SQL statements executed while monitoring is active, including caller/source context and counts/runtime measures depending on release. SWLT consumes runtime information and static code-analysis findings to build a worklist of candidates whose technical issue is both detectable and actually used. This is particularly useful in S/4HANA migration/performance programs where thousands of static findings exist but only a subset are hot in production.
When to use it
Use SQLM when you need workload evidence over time rather than one user trace: repeated expensive statements, SQL called millions of times, custom objects that are actually executed, or before/after monitoring during tuning. Use SWLT to prioritize remediation based on static issue plus dynamic execution relevance. Do not leave monitoring active without operational planning on very high-volume systems; choose scope/duration appropriate to the goal and follow system guidance.
How it fits the stack
SQLM complements ATC/Code Inspector, SCMON/usage data, ST05 and SAT. ATC can say code pattern X is risky; SQLM can say whether it actually runs and how often. SWLT brings those views together for prioritization. HANA DB tools show server-side expensive statements, but SQLM's ABAP source attribution is valuable for finding the custom source position responsible. Custom Code Migration apps use similar evidence-driven principles for S/4HANA remediation.
A worked example
A conversion program produces 20,000 ATC SQL findings. Rather than treating all equally, the team enables SQL monitoring for a representative business period, then uses SWLT to focus on frequently executed custom statements with high runtime and known static issues. A rarely executed month-end utility is scheduled later, while an inefficient SELECT inside a transaction used thousands of times daily is fixed first. This turns a theoretical backlog into a business-relevant performance plan.
How to choose
- Use ST05 for one reproducible request; use SQLM when you need aggregated runtime evidence across many executions.
- Combine runtime evidence with ATC/static findings before prioritizing large remediation backlogs.
- Choose monitoring windows that include representative business cycles.
- Filter by package/component/custom code where possible to keep analysis actionable.
- Retest after remediation to confirm runtime/statement count changed as expected.
Common pitfalls
- Prioritizing solely by static severity without checking whether code is ever executed.
- Treating the single slowest SQL as the biggest workload cost while ignoring a moderately slow statement executed millions of times.
- Collecting monitoring data during an unrepresentative quiet period.
- Leaving old monitor data mixed with a new release and drawing incorrect comparisons.
- Assuming SQLM itself explains the HANA execution plan; use ST05/PlanViz/DB tools when deeper DB analysis is required.
ECC, S/4HANA and clean core
SQLM/SWLT are particularly valuable in S/4HANA custom-code optimization and conversion projects because the objective is not only syntax compatibility but productive workload efficiency. HANA simplifies some access paths while making set-oriented design and high-frequency round trips more visible. Availability and exact UI/tooling vary by ABAP platform release and cloud deployment.
Whose problem this is
Performance/ABAP teams operate the analysis, Basis coordinates productive monitoring windows, and application owners confirm representative workloads. Program owners fix and retest the high-priority candidates. Architecture/governance teams can use results to enforce evidence-based modernization rather than blanket rewrites.
Related SAP objects
Reviewed pages this object connects to in the ERPClimb knowledge graph.
Source: ERPClimb — https://erpclimb.com/sap-technical-topics/sql-monitor-sqlm-swltERPClimb is an independent platform and is not affiliated with SAP SE. Reference pages are written and reviewed by SAP consultants for learning and troubleshooting.