Upgrade to Pro — share decks privately, control downloads, hide ads and more …

10 Key Performance Indicators Spencer Brody, So...

mongodb
November 28, 2011

10 Key Performance Indicators Spencer Brody, Software Engineer, 10gen

MongoDallas 2011

That's right: you too can learn to read the omens and ensure that your MongoDB deployment stays in tip-top shape. We'll look at memory usage, file sizes, flushing, journaling, and all the special incantations that reveal MongoDB's true inner self. By the end of the talk, you'll have ten concrete steps you can take to address performance degradation before it happens. You'll also get a few tips on application design and pointers on remote monitoring.

mongodb

November 28, 2011
Tweet

More Decks by mongodb

Other Decks in Technology

Transcript

  1. Questions about speed • MongoDB is a high-performance database, but

    how do I know that I’m getting the best performance? Monday, November 28, 2011
  2. 2. serverStatus > db.serverStatus(); { "host" : "Spencer-MacBook.local", "version" :

    "1.9.1-pre-", "process" : "mongod", "uptime" : 619052, // Lots more stats... } Monday, November 28, 2011
  3. 3. Profiler > db.setProfilingLevel(2); { "was" : 0, "slowms" :

    100, "ok" : 1 } Monday, November 28, 2011
  4. 3. Profiler > db.system.profile.find() { "ts" : ISODate("2011-09-30T02:07:11.370Z"), "op" :

    "query", "ns" : "docs.spreadsheets", "nscanned" : 20001, "nreturned" : 1, "responseLength" : 241, "millis" : 1407, "client" : "127.0.0.1", "user" : "" } Monday, November 28, 2011
  5. 1. Slow operations Sun May 22 19:01:47 [conn10] query docs.spreadsheets

    ntoreturn:100 reslen:510436 nscanned:19976 { username: “Brody, Spencer”} nreturned:100 147ms Monday, November 28, 2011
  6. 2. Resident Memory > db.serverStatus().mem { "bits" : 64, //

    Need 64, not 32 "resident" : 7151, // Physical memory "virtual" : 14248, // Files + heap "mapped" : 6942 // Data files } Monday, November 28, 2011
  7. 2. Resident Memory > db.stats() { "db" : "docs", "collections"

    : 3, "objects" : 805543, "avgObjSize" : 5107.312096312674, "dataSize" : 4114159508, // ~4GB "storageSize" : 4282908160, // ~4GB "numExtents" : 33, "indexes" : 3, "indexSize" : 126984192, // ~126MB "fileSize" : 8519680000, // ~8.5GB "ok" : 1 } Monday, November 28, 2011
  8. 3. Page faults > db.serverStatus().extra_info { "note" : "fields vary

    by platform", “heap_usage_bytes” : 210656, “page_faults” : 2381 } Monday, November 28, 2011
  9. 4. Write lock percentage > db.serverStatus().globalLock { "totalTime" : 2809217799,

    "lockTime" : 13416655, "ratio" : 0.004775939766854653, } Monday, November 28, 2011
  10. Concurrency • One writer OR many readers • Global RWlock

    • Yields on long-running ops and if we’re likely to go to disk. Monday, November 28, 2011
  11. 5. Background Flushing > db.serverStatus().backgroundFlushing { "flushes" : 5634, "total_ms"

    : 83556, "average_ms" : 14.830670926517572, "last_ms" : 4, "last_finished" : ISODate("2011-09-30T03:30:59.052Z") } Monday, November 28, 2011
  12. Disk utilization iostat -x 2 Linux 2.6.38-12-generic (ubuntu) 11/17/2011 _x86_64_

    (8 CPU) avg-cpu: %user %nice %system %iowait %steal %idle 10.69 0.62 1.58 0.47 0.00 86.63 Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await r_await w_await svctm %util sda 0.00 5.89 0.10 0.36 3.80 25.10 123.85 0.02 48.10 0.84 61.27 0.70 0.03 sdb 0.13 264.95 0.78 10.07 16.31 1103.36 206.52 2.34 215.60 23.01 230.48 3.25 3.52 Monday, November 28, 2011
  13. 6. Replication lag PRIMARY> rs.status() { "set" : "replSet", "date"

    : ISODate("2011-09-30T02:28:21Z"), "myState" : 1, "members" : [ { "_id" : 0, "name" : "Spencer-MacBook.local:30001", "health" : 1, "state" : 1, "stateStr" : "PRIMARY", "optime" : { "t" : 1317349400000, "i" : 1 }, "optimeDate" : ISODate("2011-09-30T02:23:20Z"), "self" : true }, { "_id" : 1, "name" : "Spencer-MacBook.local:30002", "health" : 1, "state" : 2, "stateStr" : "SECONDARY", "uptime" : 302, "optime" : { "t" : 1317349400000, "i" : 1 }, "optimeDate" : ISODate("2011-09-28T10:17:47Z"), "lastHeartbeat" : ISODate("2011-09-30T02:28:19Z"), "pingMs" : 0 } ], "ok" : 1 } Monday, November 28, 2011
  14. 7. Reader and Writer queues > db.serverStatus().globalLock { "totalTime" :

    2809217799, "lockTime" : 13416655, "ratio" : 0.004775939766854653, "currentQueue" : { "total" : 1, "readers" : 1, "writers" : 0 }, "activeClients" : { "total" : 2, "readers" : 1, "writers" : 1 } } Monday, November 28, 2011
  15. 7. Reader and Writer queues > db.currentOp() { "inprog" :

    [ { "opid" : 6996, "active" : true, "lockType" : "read", "waitingForLock" : true, "secs_running" : 1, "op" : "query", "ns" : "docs.spreadsheets", "query" : { “username” : “Brody, Spencer” }, "client" : "10.71.194.111:51015", "desc" : "conn", "threadId" : "0x152693000", "numYields" : 0 }, ] } Monday, November 28, 2011
  16. 9. Network speed > db.serverStatus().network { "bytesIn" : 877291, "bytesOut"

    : 846300, "numRequests" : 9186 } Monday, November 28, 2011
  17. 10. Fragmentation db.spreadsheets.stats() { "ns" : "docs.spreadhseets", "size" : 8200046932,

    // ~8GB "storageSize" : 11807223808, // ~11GB "paddingFactor" : 1.4302, "totalIndexSize" : 345964544, // ~345MB "indexSizes" : { "_id_" : 66772992, “username_1_filename_1” : 146079744, “username_1_updated_at_1” : 133111808 }, "ok" : 1 } Monday, November 28, 2011
  18. storageSize / size > 2 • Might not be reclaiming

    free space fast enough • Padding factor might not be correctly calibrated • db.spreadsheets.runCommand(“compact”) Monday, November 28, 2011
  19. paddingFactor > 2 • You might have the wrong data

    model • You might be growing documents too much • Should review Schema Design Monday, November 28, 2011