managing-questdb

name	managing-questdb
description	Use when working with Questdb — questDB time-series database management — monitor tables, partitions, ingestion throughput, query performance, and server health. Use when inspecting table schemas, debugging slow queries, reviewing WAL status, or auditing storage utilization.
connection_type	questdb
preload	false

Managing QuestDB

Manage and monitor QuestDB time-series database — tables, partitions, ingestion, queries, and server health.

Discovery Phase

#!/bin/bash

QUESTDB_API="${QUESTDB_URL:-http://localhost:9000}"

qdb_query() {
    curl -s -G "$QUESTDB_API/exec" --data-urlencode "query=$1" | jq -r '.dataset[] | @tsv'
}

echo "=== Server Status ==="
curl -s "$QUESTDB_API/status" | jq '.' 2>/dev/null || echo "Status endpoint not available"

echo ""
echo "=== Tables ==="
qdb_query "SELECT name, partitionBy, maxUncommittedRows, walEnabled, directoryName
           FROM tables()
           ORDER BY name
           LIMIT 20;" | column -t

echo ""
echo "=== Table Sizes ==="
qdb_query "SELECT table_name, row_count, disk_size
           FROM table_storage()
           ORDER BY disk_size DESC
           LIMIT 15;" | column -t

echo ""
echo "=== Table Columns (sample) ==="
qdb_query "SELECT table_name, column_name, column_type, indexed, indexValueBlockCapacity
           FROM table_columns('${QUESTDB_TABLE:-trades}')
           LIMIT 20;" | column -t

Analysis Phase

#!/bin/bash

QUESTDB_API="${QUESTDB_URL:-http://localhost:9000}"

qdb_query() {
    curl -s -G "$QUESTDB_API/exec" --data-urlencode "query=$1" | jq -r '.dataset[] | @tsv'
}

qdb_meta() {
    curl -s -G "$QUESTDB_API/exec" --data-urlencode "query=$1" | jq '.'
}

echo "=== Partition Info ==="
qdb_query "SELECT * FROM table_partitions('${QUESTDB_TABLE:-trades}')
           ORDER BY index DESC
           LIMIT 10;" | column -t

echo ""
echo "=== WAL Status ==="
qdb_query "SELECT * FROM wal_tables()
           LIMIT 10;" | column -t

echo ""
echo "=== Query Performance (sample) ==="
RESULT=$(qdb_meta "SELECT count() FROM ${QUESTDB_TABLE:-trades}")
echo "$RESULT" | jq '{count: .dataset[0][0], timing: .timings}'

echo ""
echo "=== Recent Data Check ==="
qdb_query "SELECT min(timestamp), max(timestamp), count()
           FROM ${QUESTDB_TABLE:-trades}
           WHERE timestamp > dateadd('d', -1, now());" | column -t

echo ""
echo "=== Active Writers ==="
qdb_query "SELECT * FROM writer_pool()
           LIMIT 10;" | column -t

 
 
curl -s  --data-urlencode  \
  | jq -r  | column -t

 
 
qdb_query  | column -t

Output Format

TABLES
Name             Partition By   WAL Enabled   Max Uncommitted
<table-name>     DAY            true          <n>

TABLE SIZES
Table            Rows           Disk Size
<table-name>     <n>            <bytes>

PARTITIONS
Index    Name         Row Count    Size
<n>      <partition>  <n>          <bytes>

WAL STATUS
Table            Seq Txn    Writer Txn   Segment Count
<table-name>     <n>        <n>          <n>

DATA FRESHNESS
Min Timestamp     Max Timestamp     Count (24h)
<timestamp>       <timestamp>       <n>

Anti-Hallucination Rules

1. NEVER assume resource names — always discover via CLI/API in Phase 1 before referencing in Phase 2.
2. NEVER fabricate metric names or dimensions — verify against the service documentation or --help output.
3. NEVER mix CLI commands between service versions — confirm which version/API you are targeting.
4. ALWAYS use the discovery → verify → analyze chain — every resource referenced must have been discovered first.
5. ALWAYS handle empty results gracefully — an empty response is valid data, not an error to retry.

Counter-Rationalizations

Shortcut	Counter	Why
"I'll skip discovery and check known resources"	Always run Phase 1 discovery first	Resource names change, new resources appear — assumed names cause errors
"The user only asked for a quick check"	Follow the full discovery → analysis flow	Quick checks miss critical issues; structured analysis catches silent failures
"Default configuration is probably fine"	Audit configuration explicitly	Defaults often leave logging, security, and optimization features disabled
"Metrics aren't needed for this"	Always check relevant metrics when available	API/CLI responses show current state; metrics reveal trends and intermittent issues
"I don't have access to that"	Try the command and report the actual error	Assumed permission failures prevent useful investigation; actual errors are informative