A Software Engineer at San Diego Gas & Electric (SDG&E) plays a pivotal role in shaping the company's technological landscape. As part of a team focused on delivering innovative solutions, you will contribute to projects that enhance operational efficiency, improve customer experiences, and support the company’s mission of providing safe and reliable energy. Your work will directly impact the functionality of various products and services, ranging from customer management systems to grid management technologies. The significance of your role cannot be overstated. You will engage in projects that not only affect internal operations but also have far-reaching implications for the communities served by SDG&E. The complexity of the tasks you will tackle, from software development to systems integration, requires a strategic mindset and a passion for continuous improvement. This position offers a unique opportunity to work at the intersection of technology and community service, making it both rewarding and impactful. At SDG&E, you will be part of a collaborative environment where you can leverage cutting-edge technologies and methodologies. The role demands creativity and technical acumen, inviting you to solve real-world problems while contributing to a culture of sustainability and responsibility.
Phone or Virtual Interview
reportedInitial 30-45 minute interview with an HR representative and possibly a technical lead to assess your background and experiences.
What to demonstrate
- Initial 30-45 minute interview with an HR representative and possibly a technical lead to assess your background and experiences
- Depth in Behavioral Interviewing
How to prepare
- Answer aloud and timed: Describe a situation where you had to work as part of a team to achieve a goal.
- Answer aloud and timed: Can you share an experience where you faced a conflict and how you resolved it?
In-Person Interview
reportedSeries of back-to-back interviews with various team members, including managers and directors, focusing on behavioral questions and technical skills.
What to demonstrate
- Series of back-to-back interviews with various team members
- Including managers and directors
- Focusing on behavioral questions and technical skills
How to prepare
- Answer aloud and timed: Tell me about a time you demonstrated leadership in a project.
- Answer aloud and timed: How do you handle feedback from peers or supervisors?
Informal Team Meeting
reportedOpportunity to meet team members in informal settings, such as lunch, to gauge team dynamics.
What to demonstrate
- Opportunity to meet team members in informal settings, such as lunch, to gauge team dynamics
- Depth in Behavioral Interviewing
How to prepare
- Answer aloud and timed: What motivates you to perform your best at work?
- Answer aloud and timed: Explain a technical project you worked on and your specific contributions.
PracHub editorial advice for the preparation topics above.
Research the Company
Understand SDG&E's mission, values, and community initiatives; this will help you articulate your fit during the interview.
Practice the STAR Technique
Use the STAR (Situation, Task, Action, Result) method to structure your responses to behavioral questions effectively.
Maintain a Collaborative Mindset
Emphasize teamwork and collaboration in your answers, reflecting the company's emphasis on community and collective success.
Engage with Interviewers
Prepare thoughtful questions to ask your interviewers, demonstrating your interest in the role and the company's projects.
Choose a category, try a prompt, then open its approach, worked solution or follow-up when you need it.
Find overlapping job attempts and peak concurrency from lease records
A day of job_run history yields about 50,000,000 attempt records: (job_run_id, job_type, attempt, started_at, finished_at which is NULL when the worker died, lease_expires_at). Leases expire on a clock, so a job that outran its lease ran twice. Produce (a) every job_run_id whose attempts overlapped in wall-clock time and (b) the peak number of simultaneously running attempts per job_type with the minute it occurred. Target O(n log n). State how you treat a NULL finished_at and what clock skew does to your answer.
Approach
- Define the interval before sorting anything: an attempt occupies [started_at, COALESCE(finished_at, lease_expires_at)). finished_at is observed and lease_expires_at is only a promise, so every attempt without a finish contributes an estimate and the whole result is a lower bound on overlap rather than an exact count.
- For peak concurrency, sweep: emit 2n endpoints, sort by (timestamp, kind) with ends ordered before starts at equal timestamps, then walk the sequence maintaining a counter per job_type and record each type's maximum with its timestamp. O(n log n) dominated by the sort, O(n) space, or O(1) extra if the sort is external and the walk streams.
- For overlap detection, do not compare attempts pairwise. A single global sort by (job_run_id, started_at) gives both the grouping and the order; within a group, keep the maximum end seen so far and report an overlap exactly when the next start is less than that running maximum, which is one linear pass after the sort.
- Half-open intervals matter and are easy to get wrong: with closed intervals an attempt ending at the same millisecond another begins reads as concurrency two, and across 50,000,000 records that artefact swamps the real signal.
Follow-up
- A handler is not idempotent and you have found 400 overlapping jobs. Which of them actually caused damage, and what would you query to find out?
- Peak concurrency for one job_type is 4 against a configured cap of 4. Is the cap working, or is the data hiding attempts that never started?
Collapse a redelivered event batch into per-aggregate high-water marks
You drain a batch of up to 5,000,000 events, each (aggregate_id BIGINT, aggregate_version INT, event_type, payload). The log guarantees order within one aggregate only; the batch merges 64 partitions, and a relay failover has redelivered a range, so an older version for an aggregate can appear after a newer one. Given a map of last_applied_version per aggregate, produce the events worth applying, at most one per (aggregate_id, version), plus the count discarded. Target O(n) time. State the memory for 2,000,000 distinct aggregates and what you do when it does not fit.
Approach
- One pass, one hash map from aggregate_id to the highest version kept, and a discard counter. An event whose version is at or below last_applied_version for its aggregate is dropped without further work, which is the whole reason the event carries its version rather than a delta. O(n) expected time, O(d) space in distinct aggregates.
- Keep the maximum, never the last occurrence. The redelivered range means the final appearance of an aggregate in the batch can be an older version than one seen earlier in the same batch, so last-wins applies stale state over newer state and the projection regresses with no error anywhere.
- Cost the memory instead of calling it large: an 8-byte key plus a 4-byte version is 12 bytes of payload, and an open-addressed table held at a 0.7 load factor costs roughly 17 bytes per entry before per-slot metadata, so 2,000,000 aggregates is tens of megabytes in a native layout and several times that in a runtime that boxes both key and value.
- If the distinct set exceeds memory, partition on hash(aggregate_id) mod P and reduce each partition independently. Every event for one aggregate hashes to the same partition, so the per-partition result is exact and the merge is concatenation rather than a second reduction.
Follow-up
- The payload is a patch rather than a snapshot, so applying only the highest version loses the intermediate changes. What changes in your reduction?
- How do you detect that version 7 arrived while version 6 was never delivered, and what should the consumer do about the gap?
Merge partitioned event streams into one ordered feed with bounded lateness
The read-model service consumes 64 log partitions carrying about 4,000 events per second in total. Each partition is ordered within itself, but partitions drift by up to 30 seconds, and the activity feed must present a tenant's events in occurred_at order. Produce the merge. State its complexity, the buffer it requires in events and in bytes, what happens when one partition is idle, and what you do with an event that arrives after you have already emitted its position. Payloads average 1 KB.
Approach
- Merge with a min-heap over the 64 partition heads keyed on (occurred_at, event_id): O(log P) per event and O(n log P) overall. The tie-break on event_id is what makes the output deterministic when two partitions carry the same millisecond, which matters because the feed is paginated and a non-deterministic order reorders pages under the reader.
- Emitting the heap head is only correct once every partition has produced everything up to that timestamp, so the emit condition is a watermark: the minimum across partitions of the highest occurred_at seen, less the allowed lateness. Events are held until the watermark passes them, which is what turns individually ordered streams into a jointly ordered one.
- Size the buffer from the lateness rather than guessing: 4,000 events per second times 30 seconds is 120,000 buffered events, and at 1 KB each about 120 MB of heap. That number is the real price of the ordering guarantee and belongs in front of whoever asked for it.
- Handle the idle partition explicitly, because it fails the feed rather than corrupting it: a partition with no traffic never advances its own maximum, so the watermark freezes and output stops entirely. Either every partition emits a periodic idle marker carrying the broker's current time, or the watermark falls back to wall clock for a partition silent beyond a threshold.
Follow-up
- The lateness budget is raised to five minutes. What is the new buffer, and what besides memory changes?
- The consumer restarts. Where does it resume from, and what does the feed look like for the first 30 seconds?
Hold a per-tenant active cap against concurrent creates
A tenant on the standard plan may hold at most 50 resources with status='active'. The create handler runs SELECT count(*) FROM resource WHERE tenant_id = $1 AND status = 'active', compares to 50, then inserts. Two creates arrive 3 ms apart on different instances and the tenant lands at 51. Name the anomaly, say whether PostgreSQL 16 READ COMMITTED or REPEATABLE READ prevents it and why, then give an implementation that holds the cap at READ COMMITTED with the exact statements. Finally, say what changes when the cap is 'at most one running export per tenant' on job_run.
Approach
- Name it: write skew. The two transactions read an overlapping set and write disjoint rows, so there is no row-level conflict for the engine to detect and each commit is individually legal.
- Rule out the levels precisely. READ COMMITTED takes a fresh snapshot per statement and takes no lock on the counted rows, so both see 49. PostgreSQL's REPEATABLE READ is snapshot isolation: it removes non-repeatable reads and phantoms within the snapshot but still admits write skew, because the anomaly is not a re-read of a changed row, it is a read of a set that a concurrent transaction invalidates. Only SERIALIZABLE closes it, by tracking the read dependency and aborting one transaction with SQLSTATE 40001 — a guarantee that exists only if the application re-runs the whole transaction from the read.
- Convert the set predicate into a single-row conflict: keep tenant.active_resource_count and run UPDATE tenant SET active_resource_count = active_resource_count + 1 WHERE tenant_id = $1 AND active_resource_count < 50 in the same transaction as the INSERT. Zero affected rows is the cap, returned as 409. The row lock serialises the decision at any isolation level, and contention is bounded to one tenant's row — which is also the fair-scheduling unit, unlike a global counter that would convoy every tenant behind one row.
- State the cost you just took on: a counter is a second source of truth that can drift, so every path that changes status must adjust it inside the same transaction, and a periodic reconciliation has to exist, with resource_revision as the authority for what the count should have been.
Follow-up
- A resource moves from archived back to active. Which statements change, and what breaks if the counter update and the status change land in different transactions?
- The cap becomes plan-dependent and a plan can change mid-month. Where does the number 50 live, and who reads it?
Explain why the owner filter ignores the listing index
The only index on resource is (tenant_id, status, updated_at DESC, resource_id DESC). A new endpoint returns one user's resources across all statuses, newest created first: WHERE tenant_id = $1 AND owner_user_id = $2 ORDER BY created_at DESC LIMIT 20. On a tenant with 2M rows it takes 900 ms and EXPLAIN shows a sort above a large scan. Explain precisely why the existing index cannot serve it, give the index that can, and state which of these the new index still will not help: owner_user_id alone across tenants; the same query ordered by updated_at. PostgreSQL 16.
Approach
- Separate the two jobs an index does. For filtering, a composite btree is seekable only on a left prefix, so with no predicate on status the scan can at best range over tenant_id and test owner_user_id per row; PostgreSQL 16 has no btree skip scan to jump the unconstrained column.
- For ordering, the index is sorted by (status, updated_at) within a tenant and not by created_at, so the LIMIT cannot stop early: every matching row is read and then sorted. That is the 'Sort Method: top-N heapsort' line, and it is why the plan reads 2M rows to answer with 20.
- Derive the replacement from the access path — equality, equality, then the ordering column: CREATE INDEX CONCURRENTLY ON resource (tenant_id, owner_user_id, created_at DESC). The scan seeks to the (tenant, owner) range and walks 20 entries in order, so the Sort node disappears along with the row-read.
- Treat INCLUDE (title, status) as conditional, not free. An index-only scan still visits the heap for any row whose page is not marked all-visible, so on a table taking 1.2k writes/second the win depends on autovacuum keeping the visibility map current, and the wider index costs more on every insert.
Follow-up
- 90% of rows are status='active'. Would a partial index WHERE status = 'active' change your answer, and for which of the three queries?
- A dashboard runs this for 40 owners in one page load. What changes about the design?
Explain a technical project you worked on and your specific contributions.
Explain a technical project you worked on and your specific contributions.
Approach
- Clarify what is being asked and what a complete answer contains.
- State your assumptions explicitly before working the problem.
- Say what you would check first and why it is the highest-information step.
- Work from the requirement backwards to the design.
Follow-up
- What assumption would you test first?
- How would you know your answer was wrong?
Describe the tools or technologies you are most comfortable with.
Describe the tools or technologies you are most comfortable with.
Approach
- Clarify what is being asked and what a complete answer contains.
- State your assumptions explicitly before working the problem.
- Say what you would check first and why it is the highest-information step.
- Work from the requirement backwards to the design.
Follow-up
- What assumption would you test first?
- How would you know your answer was wrong?
How do you ensure the quality and performance of your code?
How do you ensure the quality and performance of your code?
Approach
- Clarify what is being asked and what a complete answer contains.
- State your assumptions explicitly before working the problem.
- Say what you would check first and why it is the highest-information step.
- Work from the requirement backwards to the design.
Follow-up
- What assumption would you test first?
- How would you know your answer was wrong?
Describe a complex problem you solved and the steps you took to address it.
Describe a complex problem you solved and the steps you took to address it.
Approach
- Clarify what is being asked and what a complete answer contains.
- State your assumptions explicitly before working the problem.
- Say what you would check first and why it is the highest-information step.
- Work from the requirement backwards to the design.
Follow-up
- What assumption would you test first?
- How would you know your answer was wrong?
If you were given a project with tight deadlines, how would you prioritize tasks?
If you were given a project with tight deadlines, how would you prioritize tasks?
Approach
- Clarify what is being asked and what a complete answer contains.
- State your assumptions explicitly before working the problem.
- Say what you would check first and why it is the highest-information step.
- Work from the requirement backwards to the design.
Follow-up
- What assumption would you test first?
- How would you know your answer was wrong?
How do you approach debugging an issue in your code?
How do you approach debugging an issue in your code?
Approach
- Establish what changed and when, before forming any theory.
- Pick a bisection that eliminates candidates whichever way it turns out.
- Check the instrumentation before believing the symptom.
- Separate the trigger from the cause; the deploy is rarely the bug.
Follow-up
- What would you look at first, and what would it rule out?
- How would you tell a cause from a coincidence here?
Built from the rounds and topics San Diego Gas & Electric candidates report.
Prepare, practise & reflect
One practical outcome each day. Spend longer where you need it.
0 / 7 done01Map the San Diego Gas & Electric loop
- Write out the reported sequence: Phone or Virtual Interview, In-Person Interview, Informal Team Meeting.
- For each round, write one sentence on what it is judging, from the description above, and mark the one you are least ready for.
Deliverable: A one-page map of the 3 reported rounds, with the weakest marked.
02Work Behavioral Interviewing
- Spend the session on Behavioral Interviewing, which San Diego Gas & Electric candidates report being tested on.
- Write one worked example in Behavioral Interviewing and time yourself on it.
Deliverable: One timed worked example in Behavioral Interviewing.
03Work STAR Interview Technique
- Spend the session on STAR Interview Technique, which San Diego Gas & Electric candidates report being tested on.
- Write one worked example in STAR Interview Technique and time yourself on it.
Deliverable: One timed worked example in STAR Interview Technique.
04Work Situational Questions
- Spend the session on Situational Questions, which San Diego Gas & Electric candidates report being tested on.
- Write one worked example in Situational Questions and time yourself on it.
Deliverable: One timed worked example in Situational Questions.
05Answer out loud: Behavioral / Leadership
- Answer aloud, timed: Describe a situation where you had to work as part of a team to achieve a goal.
- Answer aloud, timed: Can you share an experience where you faced a conflict and how you resolved it?
Deliverable: Spoken answers to 2 reported Behavioral / Leadership question(s), under time.
06Answer out loud: Technical / Domain Knowledge
- Answer aloud, timed: Explain a technical project you worked on and your specific contributions.
- Answer aloud, timed: Describe the tools or technologies you are most comfortable with.
Deliverable: Spoken answers to 2 reported Technical / Domain Knowledge question(s), under time.
07Answer out loud: Problem-Solving / Case Studies
- Answer aloud, timed: Describe a complex problem you solved and the steps you took to address it.
- Answer aloud, timed: How do you approach debugging an issue in your code?
Deliverable: Spoken answers to 2 reported Problem-Solving / Case Studies question(s), under time.
Expand any day for tasks and deliverables. Your progress is saved on this device.
Behavioural rounds judge the decision you made and what it cost.
Describe a situation where you had to work as part of a team to achieve a goal.
Describe a situation where you had to work as part of a team to achieve a goal.
Approach
- Pick a story where you made the decision, not one where you watched it.
- State the situation in two sentences and spend the rest on the reasoning.
- Give the blast radius: what could have broken, and what you measured.
- Name the disagreement and how you resolved it with evidence.
Follow-up
- What would you do differently if you ran that again?
- How did you know your change caused the improvement?
Can you share an experience where you faced a conflict and how you resolved it?
Can you share an experience where you faced a conflict and how you resolved it?
Approach
- Pick a story where you made the decision, not one where you watched it.
- State the situation in two sentences and spend the rest on the reasoning.
- Give the blast radius: what could have broken, and what you measured.
- Name the disagreement and how you resolved it with evidence.
Follow-up
- What would you do differently if you ran that again?
- How did you know your change caused the improvement?
Tell me about a time you demonstrated leadership in a project.
Tell me about a time you demonstrated leadership in a project.
Approach
- Pick a story where you made the decision, not one where you watched it.
- State the situation in two sentences and spend the rest on the reasoning.
- Give the blast radius: what could have broken, and what you measured.
- Name the disagreement and how you resolved it with evidence.
Follow-up
- What would you do differently if you ran that again?
- How did you know your change caused the improvement?
How do you handle feedback from peers or supervisors?
How do you handle feedback from peers or supervisors?
Approach
- Pick a story where you made the decision, not one where you watched it.
- State the situation in two sentences and spend the rest on the reasoning.
- Give the blast radius: what could have broken, and what you measured.
- Name the disagreement and how you resolved it with evidence.
Follow-up
- What would you do differently if you ran that again?
- How did you know your change caused the improvement?
What motivates you to perform your best at work?
What motivates you to perform your best at work?
Approach
- Pick a story where you made the decision, not one where you watched it.
- State the situation in two sentences and spend the rest on the reasoning.
- Give the blast radius: what could have broken, and what you measured.
- Name the disagreement and how you resolved it with evidence.
Follow-up
- What would you do differently if you ran that again?
- How did you know your change caused the improvement?
Why do you want to work for SDG&E?
Why do you want to work for SDG&E?
Approach
- Pick a story where you made the decision, not one where you watched it.
- State the situation in two sentences and spend the rest on the reasoning.
- Give the blast radius: what could have broken, and what you measured.
- Name the disagreement and how you resolved it with evidence.
Follow-up
- What would you do differently if you ran that again?
- How did you know your change caused the improvement?
How do you see yourself contributing to a community-focused company?
How do you see yourself contributing to a community-focused company?
Approach
- Pick a story where you made the decision, not one where you watched it.
- State the situation in two sentences and spend the rest on the reasoning.
- Give the blast radius: what could have broken, and what you measured.
- Name the disagreement and how you resolved it with evidence.
Follow-up
- What would you do differently if you ran that again?
- How did you know your change caused the improvement?
How would you approach a situation where you disagree with a team member on a technical solution?
How would you approach a situation where you disagree with a team member on a technical solution?
Approach
- Pick a story where you made the decision, not one where you watched it.
- State the situation in two sentences and spend the rest on the reasoning.
- Give the blast radius: what could have broken, and what you measured.
- Name the disagreement and how you resolved it with evidence.
Follow-up
- What would you do differently if you ran that again?
- How did you know your change caused the improvement?
- 01
Describe a situation where you had to work as part of a team to achieve a goal.
- 02
Can you share an experience where you faced a conflict and how you resolved it?
- 03
Tell me about a time you demonstrated leadership in a project.
- 04
How do you handle feedback from peers or supervisors?
What is the interview difficulty level, and how much preparation time is typical?
The interview process is generally considered moderate in difficulty, focusing heavily on behavioral questions. Candidates typically benefit from several weeks of preparation time to review relevant technical concepts and practice their responses.
San Diego Gas & Electric Software Engineer candidate reports ↗What differentiates successful candidates?
Successful candidates often demonstrate a strong alignment with SDG&E's values, showcasing both technical proficiency and a genuine interest in community service. They effectively communicate their problem-solving approaches and exhibit a collaborative mindset.
San Diego Gas & Electric Software Engineer candidate reports ↗What is the culture and working style like at SDG&E?
The culture at SDG&E emphasizes collaboration, innovation, and community impact. Employees are encouraged to contribute ideas and work together to solve challenges, fostering a supportive and engaging work environment.
San Diego Gas & Electric Software Engineer candidate reports ↗What is the typical timeline from the initial screen to an offer?
The timeline can vary but generally spans from a few weeks to a couple of months, depending on the number of interview rounds and the scheduling of additional assessments.
San Diego Gas & Electric Software Engineer candidate reports ↗Are there remote work or hybrid expectations?
While many roles may offer hybrid options, it is essential to clarify specific arrangements during the interview process, as team dynamics and project needs can influence work location flexibility.
San Diego Gas & Electric Software Engineer candidate reports ↗What topics does San Diego Gas & Electric test in interviews?
San Diego Gas & Electric interviews most often cover Panel Interviewing, Behavioral Interviewing, Interview Preparation, Communication Skills, and Stakeholder Management. The exact emphasis depends on the specific role you apply for.
San Diego Gas & Electric Software Engineer candidate reports ↗Sources & methodology 3 sources ↗
No official company page is cited. Rounds and questions come from candidate reports and PracHub editorial material; each source shows the date it was read.
- 01San Diego Gas & Electric Software Engineer candidate reports ↗
Company-reported rounds, questions and FAQ.
Candidate reports · Accessed 2026-09-22 - 02PracHub Software Engineer practice ↗
PracHub practice material, not company-reported.
PracHub page · Accessed 2026-09-22 - 03PracHub preparation framework ↗
PracHub preparation guidance.
PracHub page · Accessed 2026-09-22
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