VReplication: add table for logging stream errors, state changes and key workflow steps #7831

rohit-nayak-ps · 2021-04-12T20:18:22Z

Description

This PR adds a new table to the _vt sidecar database. The _vt.vreplication_log table will record certain types of events. To start with we record

stream creation along with stream parameters
stream errors
state changes
key workflow steps (currently start and end of the copy phase) (Todo)

CREATE TABLE IF NOT EXISTS _vt.vreplication_log (
	id BIGINT(20) AUTO_INCREMENT,
	vrepl_id INT NOT NULL,
	type VARBINARY(256) NOT NULL,
	state VARBINARY(100) NOT NULL,
	created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
	updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
	message text NOT NULL,
	count BIGINT(20) NOT NULL DEFAULT 1,
	PRIMARY KEY (id))

The value of the message will usually be a string. In the case of stream inserts it records all the parameters including the binlogsource field.

Before inserting a new row we check if the latest message matches the state and message of the new message and if it does then it increments the count. This prevents any repeated errors from spamming the table.

Tests

When I tried adding the queries related to the vreplication_log to expect them during other vreplication tests it lead to a huge number of updates to existing tests and also created race conditions and other flakiness. For now we ignore these queries
during the workflow and test the log insertion code separately.

Checklist

Should this PR be backported?
Tests were added or are not required
Documentation was added or is not required

Impacted Areas in Vitess

Components that this PR will affect:

VReplication
VTAdmin

rohit-nayak-ps · 2021-04-12T22:43:48Z

Sample output from local example

mysql> select * from _vt.vreplication_log where vrepl_id = 1 order by id asc \G
*************************** 1. row ***************************
        id: 1
  vrepl_id: 1
      type: Stream Created
     state: Stopped
created_at: 2021-04-13 21:26:36
updated_at: 2021-04-13 21:26:36
   message: {"cell":"","db_name":"vt_customer","id":"1","max_replication_lag":"9223372036854775807","max_tps":"9223372036854775807","pos":"","source":"keyspace:\"commerce\" shard:\"0\" filter:\u003crules:\u003cmatch:\"customer\" filter:\"select * from customer\" \u003e rules:\u003cmatch:\"corder\" filter:\"select * from corder\" \u003e \u003e ","state":"Stopped","tablet_types":"","time_updated":"1618341996","transaction_timestamp":"0","workflow":"commerce2customer"}
     count: 1
*************************** 2. row ***************************
        id: 2
  vrepl_id: 1
      type: State Changed
     state: Running
created_at: 2021-04-13 21:26:36
updated_at: 2021-04-13 21:26:36
   message: 
     count: 1
*************************** 3. row ***************************
        id: 3
  vrepl_id: 1
      type: State Changed
     state: Copying
created_at: 2021-04-13 21:26:36
updated_at: 2021-04-13 21:26:36
   message: 
     count: 1
*************************** 4. row ***************************
        id: 4
  vrepl_id: 1
      type: Started Copy Phase
     state: Copying
created_at: 2021-04-13 21:26:36
updated_at: 2021-04-13 21:26:36
   message: Copy phase started for 2 table(s)
     count: 1
*************************** 5. row ***************************
        id: 5
  vrepl_id: 1
      type: Ended Copy Phase
     state: Copying
created_at: 2021-04-13 21:26:37
updated_at: 2021-04-13 21:26:37
   message: Copy phase completed at gtid fdbc7d6b-9c8d-11eb-b544-04ed332e05c2:1-43
     count: 1
*************************** 6. row ***************************
        id: 6
  vrepl_id: 1
      type: State Changed
     state: Running
created_at: 2021-04-13 21:26:37
updated_at: 2021-04-13 21:26:37
   message: 
     count: 1
*************************** 7. row ***************************
        id: 7
  vrepl_id: 1
      type: State Changed
     state: Stopped
created_at: 2021-04-13 21:26:39
updated_at: 2021-04-13 21:26:39
   message: 
     count: 2
*************************** 8. row ***************************
        id: 8
  vrepl_id: 1
      type: Stream Deleted
     state: 
created_at: 2021-04-13 21:26:39
updated_at: 2021-04-13 21:26:39
   message: 
     count: 1
8 rows in set (0.00 sec)

ajm188

This looks amazing!! I'm very excited to try this out ❤️

ajm188 · 2021-04-17T01:37:39Z

go/vt/vttablet/tabletmanager/vreplication/utils.go

+	// LogStateChange is used when the state of the stream changes
+	LogStateChange = "State Changed"
+
+	// TODO: LogError is not used atm. Currently irrecoverable errors, resumable errors and informational messages


👍 I'm not sure if you have any ideas about to do this more advanced error detection/categorization, but I'm happy to brainstorm with you if you want!

doeg · 2021-04-27T17:47:07Z

go/vt/vttablet/tabletmanager/vreplication/utils.go

+)
+
+const (
+	createVReplicationLog = `CREATE TABLE IF NOT EXISTS _vt.vreplication_log (


In our experiments, we were seeing the _vt.vreplication_log table created on the tablet but inaccessible from VReplicationExec:

vitess@abe8006adf7f:/vt/local$ vtctlclient VreplicationExec zone1-0000000400 "select * from _vt.vreplication_log" VreplicationExec Error: rpc error: code = Unknown desc = TabletManager.VReplicationExec on zone1-0000000400 error: invalid table name: _vt.vreplication_log: invalid table name: _vt.vreplication_log E0427 15:05:50.761692 9477 main.go:72] remote error: rpc error: code = Unknown desc = TabletManager.VReplicationExec on zone1-0000000400 error: invalid table name: _vt.vreplication_log: invalid table name: _vt.vreplication_log

@ajm188 found that the switch statements in controller_plan.go return "invalid table name" error as they've not been updated to include the _vt.vreplication_log table. We were able to patch it like this (and, we only updated one of the four switch statements for brevity):

diff --git a/go/vt/vttablet/tabletmanager/vreplication/controller_plan.go b/go/vt/vttablet/tabletmanager/vreplication/controller_plan.go index ed42cf1839..c7ac3d45d4 100644 --- a/go/vt/vttablet/tabletmanager/vreplication/controller_plan.go +++ b/go/vt/vttablet/tabletmanager/vreplication/controller_plan.go @@ -133,6 +133,7 @@ func buildUpdatePlan(upd *sqlparser.Update) (*controllerPlan, error) { }, nil case vreplicationTableName: // no-op + default: return nil, fmt.Errorf("invalid table name: %v", sqlparser.String(upd.TableExprs)) } @@ -222,7 +223,7 @@ func buildDeletePlan(del *sqlparser.Delete) (*controllerPlan, error) { func buildSelectPlan(sel *sqlparser.Select) (*controllerPlan, error) { switch sqlparser.String(sel.From) { - case vreplicationTableName, reshardingJournalTableName, copyStateTableName: + case vreplicationTableName, reshardingJournalTableName, copyStateTableName, vreplicationLogTableName: return &controllerPlan{ opcode: selectQuery, }, nil diff --git a/go/vt/vttablet/tabletmanager/vreplication/utils.go b/go/vt/vttablet/tabletmanager/vreplication/utils.go index dd89ea3bd1..9f542b8d15 100644 --- a/go/vt/vttablet/tabletmanager/vreplication/utils.go +++ b/go/vt/vttablet/tabletmanager/vreplication/utils.go @@ -26,7 +26,8 @@ import ( ) const ( - createVReplicationLog = `CREATE TABLE IF NOT EXISTS _vt.vreplication_log ( + vreplicationLogTableName = "_vt.vreplication_log" + createVReplicationLog = `CREATE TABLE IF NOT EXISTS _vt.vreplication_log ( id BIGINT(20) AUTO_INCREMENT, vrepl_id INT NOT NULL, type VARBINARY(256) NOT NULL,

... and then see the rows via VReplicationExec:

vitess@61befc15be72:/vt/local$ vtctlclient VreplicationExec zone1-0000000400 "select count(*) from _vt.vreplication_log" +----------+ | count(*) | +----------+ | 6 | +----------+

Ah, hadn't thought of VReplicationExec for this table. I think we should add it only for Select and possibly Delete, right? Insert/Update shouldn't be allowed?

Hmm, even the delete is hardcoded in multiple places for the vreplication table and will require a little more time and tests :( I am going to just make the same changes you made so it works with Select for now. Delete can be implemented in a follow-up PR.

Updating Select for now sounds great!!! 🎉 This will be amazing to have regardless!

doeg · 2021-04-27T18:07:17Z

go/vt/vttablet/tabletmanager/vreplication/utils.go

+	// Enum values for type column of _vt.vreplication_log
+
+	// LogStreamCreate is used when a row in _vt.vreplication is inserted via VReplicationExec
+	LogStreamCreate = "Stream Created"


Is it possible/reasonable/idiomatic to make a proto enum for this? That way we also get a TypeScript enum generated for us. (Otherwise, I'll have to duplicate these strings on the front-end at some point.)

I had punted on the enum: I think we discussed that this would be implemented as part of the vtadmin API around these logs.

Revisiting at VTAdmin time makes sense to me!

…icationExec and setMessage/State Signed-off-by: Rohit Nayak <rohit@planetscale.com>

Signed-off-by: Rohit Nayak <rohit@planetscale.com>

doeg

Thank you again!!! 🎉 🎉 🎉 Can't wait to show you the end result in the UI!

rohit-nayak-ps changed the title ~~Do Not Merge: VReplication: add log table~~ VReplication: add table for logging stream errors, state changes and key workflow steps Apr 12, 2021

rohit-nayak-ps mentioned this pull request Apr 12, 2021

VReplication: add table for logging stream errors, state changes and key workflow steps #7818

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rohit-nayak-ps force-pushed the rn-vr-log2 branch 3 times, most recently from f41805b to d865b2f Compare April 15, 2021 08:33

rohit-nayak-ps requested review from rafael, ajm188 and a team April 15, 2021 09:20

rohit-nayak-ps marked this pull request as ready for review April 15, 2021 09:21

rohit-nayak-ps requested a review from deepthi as a code owner April 15, 2021 09:21

ajm188 approved these changes Apr 17, 2021

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doeg reviewed Apr 27, 2021

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rohit-nayak-ps added 9 commits April 27, 2021 23:02

Create log table. Util functions to insert logs. Insert logs in VRepl…

e692693

…icationExec and setMessage/State Signed-off-by: Rohit Nayak <rohit@planetscale.com>

Ignore queries related to _vt.vreplication_log in tests

b616143

Signed-off-by: Rohit Nayak <rohit@planetscale.com>

Add test for vreplication log and fix string conversion bug

0992d39

Signed-off-by: Rohit Nayak <rohit@planetscale.com>

Fix test

1cf7286

Signed-off-by: Rohit Nayak <rohit@planetscale.com>

Add logs for start and end of the copy phase

b6d39ac

Signed-off-by: Rohit Nayak <rohit@planetscale.com>

Added comments and refactored tests

fa9de69

Signed-off-by: Rohit Nayak <rohit@planetscale.com>

Add license file. Minor refactor

4a1ab94

Signed-off-by: Rohit Nayak <rohit@planetscale.com>

Use withDDL for vreplication log queries

427cac8

Signed-off-by: Rohit Nayak <rohit@planetscale.com>

Add ability to select from vreplication_log in VReplicationExec

f57350c

Signed-off-by: Rohit Nayak <rohit@planetscale.com>

rohit-nayak-ps force-pushed the rn-vr-log2 branch from 1966c93 to f57350c Compare April 27, 2021 21:03

doeg approved these changes Apr 27, 2021

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rohit-nayak-ps merged commit 01fb7e5 into vitessio:master Apr 27, 2021

rohit-nayak-ps deleted the rn-vr-log2 branch April 27, 2021 21:38

systay added Component: VReplication Type: Enhancement Logical improvement (somewhere between a bug and feature) labels Apr 28, 2021

rafael mentioned this pull request May 4, 2021

Slack vitess 9 2021.03.16r4 tinyspeck/vitess#207

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ajm188 mentioned this pull request Jun 4, 2021

[vtctld] Add vreplication_log data to VtctldServer.GetWorkflows #8260

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VReplication: add table for logging stream errors, state changes and key workflow steps #7831

VReplication: add table for logging stream errors, state changes and key workflow steps #7831

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VReplication: add table for logging stream errors, state changes and key workflow steps #7831

VReplication: add table for logging stream errors, state changes and key workflow steps #7831

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rohit-nayak-ps commented Apr 12, 2021 • edited Loading

Description

Tests

Checklist

Impacted Areas in Vitess

rohit-nayak-ps commented Apr 12, 2021 • edited Loading

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rohit-nayak-ps commented Apr 12, 2021 •

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