Overview 

The purpose of these set of tests is to measure performance of Kiwi release. Find possible issues, bottlenecks. PERF-198 - Getting issue details... STATUS

Environment 

Software versions (Test 1-2)

• mod-oai-pmh:3.7.0-SNAPSHOT.188.  
• edge-oai-pmh:2.4.0
• mod-source-record-manager:3.2.3
• mod-source-record-storage:5.2.1
• mod-inventory-storage:22.0.1
• okapi:4.9.0

Original PTF dataset containing 1,212,039 underlying MARC records for 8.7M instances

Software versions (Test 3 with Bugfest Dataset)

• mod-oai-pmh:3.6.1
• edge-oai-pmh:2.4.0
• mod-source-record-manager:3.2.6
• mod-source-record-storage-5.2.5
• mod-inventory-storage-22.0.3
• okapi:4.9.0

Bugfest dataset containing 8,034,444 underlying MARC records for 8.3M instances

Summary

• Kiwi release was able ho harvest 7,808,200 records in 19 hr 8 min (1M records per 2 hours and 15 min).
• Average response time per request 0.874s.
• A couple of issues were found
  •  OutOfMemory exception: MODOAIPMH-374
  • Thread block issue: MODOAIPMH-374
  • When instances didn't have underlying MARC records, multiple repeating calls from mod-edge-oai-pmh to mod-oai-pmh were occurred, resulting in the end-client receiving an timeout, see MODOAIPMH-383

Test flow

Test consist of few calls:

Initial call that was performed only once

/oai/records?verb=ListRecords&metadataPrefix=marc21_withholdings&apikey=[APIKey]

Subsequent harvesting calls:

/oai/records?verb=ListRecords&apikey=[APIKey]&resumptionToken=[resumptionToken]

These calls were performed repeatedly, harvesting 100 records each time until there is no more data in [tenant]_mod_oai_pmh.instances table to harvest.

[resumptionToken] was set to 100, returning in initial call response and in each harvesting call until there is no more records to harvest. When all data has being harvested - resumptionToken will not return with the response.

Issues detected during testing

1) OutOfMemory exception. fixed in scope of MODOAIPMH-374

2) Thread block issue. fixed in scope of MODOAIPMH-374

3) DB timeout.  MODOAIPMH-383 New issue appearing when we're starting DB transferring and harvesting process at the same time. It's leads to high load on DB and it responding with timeout

Test results

Test 1

• Total Underlying SRS records: 1,212,039
• Duration: 4 hr 57 min
• Records transferred: 4,770,043 (should be 8,415,303)
• Records harvested - 20,618 X 100 = 2,061,800.

We can see here unstable part of test. This spikes on chart showing extremely increased response times. which leads to throughput gaps. At this point we still not sure this does it happening we've checked:

• RDS response times (logs) ;PGLogs.log
• mod-oai-pmh (logs);
• nginx-oai-pmh (logs);
• edge-oai-pmh (logs);
• okapi (logs);

At each point we have good response times and we can't see correlation between logs and this chart. 

Service CPU usage has reached ±200% while data transfer. And it's on 50-60% level during data harvesting. However during "unstable part" of test it has drop down to 20-25%.

• Service memory usage is stable. There is no suspects for memory leak.

Notable observations:

• While data transferring process is going on the background DB CPU usage has reached 70%-75%.
• Data transferring process has failed in 10 minutes and transfer only 4770043 from 8M records.
• Harvesting itself consumes 15% DB CPU.

Test 2

• Total Underlying SRS records: 1,212,039
• Duration: 4 hr 25 min
• Records transferred: 3,815,867 (should be 8,415,303)
• Records harvested - 22305 X 100 = 2 230 500.

Test 3 (with Bugfest Dataset)

• Underlying MARC records: 8,034,444
• Records transferred -  8,213,392
• Records harvested - 78082 X 100 = 7,808,200
• Time spent : 19 hr 8 min

Average response time for call with resumption token 0.874 ms

With new data set there is no "unstable parts" in this test

CPU usage is stable and without big spikes. As you can see there is higher CPU usage at the beginning of the test. It's data transferring  process between mod-inventory-stirage and mod-oai-pmh.

We can see here that memory usage is stable and none of containers didn't fail. 

Notable observations:

• Unstable parts of first couple of tests were made by data set:
  • Instances didn't have underlying records and this causes multiple repeating calls from mod-edge-oai-pmh to mod-oai-pmh.
  • This leads to end client to wait until oai-pmh will find records with underlying records. And often client fail with 504 getaway timeout (load balancer timeout 400 seconds).
• Timeouts in DB fixed with changing of dataset to "bugfest" like.
• Jira ticket created to handle client waits: MODOAIPMH-383