bvandeusenandClaude Opus 5.5
ad4f7d9232
Measured on dev (385a579), agent posts cut to five samples still dropped:
flush=8.8s for 990 rows, 6.6s for 680, 8.4s for 1000 — about 110 rows/s,
~9 ms a row, with rules and evaluation near zero. One random read per
row fits a random uuid4 primary key whose index no longer fits in memory:
every new row lands on a random page of it. (Inferred from the rate; the
table and index sizes have not been read.)
- steward.core.ids.time_ordered_id: a UUIDv7-layout string (48-bit ms
timestamp, then random), same 36-char shape as the stored uuid4 ids, so
no migration. Python's uuid7() arrives in 3.14; the image runs 3.13.
- Used for plugin_metrics and its hourly rollup, monitor_results,
audit_events, the docker metrics/hourly/events/logs tables, and the
traefik and unifi time series.
- MAX_SAMPLES_PER_INGEST 5 → 2 (~400 rows) for now: it fits the agent's
10 s even at the old rate, so hosts land data whichever way the new rate
comes out. Raise it once the new rate is measured.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
26 lines
1.0 KiB
Python
26 lines
1.0 KiB
Python
"""Row ids for tables that grow by time.
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A random uuid4 primary key puts every new row on a random page of the key's
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index; once that index outgrows memory, each insert waits for a disk read.
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Measured on the live instance (#5149): plugin_metrics took ~9 ms a row, about
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110 rows/s, so a host agent's post could not finish inside its 10 s timeout.
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A time-ordered id lands every new row at the index's right edge instead.
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"""
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from __future__ import annotations
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import os
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import time
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import uuid
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def time_ordered_id() -> str:
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"""A UUIDv7-layout id (RFC 9562) as a 36-character string: a 48-bit
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millisecond timestamp, then 74 random bits. Same shape and column type as
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the uuid4 ids already stored, so no table changes; Python's own uuid7()
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arrives only in 3.14."""
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ms = time.time_ns() // 1_000_000
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value = (ms & 0xFFFF_FFFF_FFFF) << 80 | int.from_bytes(os.urandom(10), "big")
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value = (value & ~(0xF << 76)) | (0x7 << 76) # version 7
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value = (value & ~(0x3 << 62)) | (0x2 << 62) # RFC 9562 variant
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return str(uuid.UUID(int=value))
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