multiple HDDs I/O #200
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hi @shreklei Excellent question. First, one clarification - we are primarily optimized to run on SSDs (and not HDDs).
To read more about YugaByte's DocDB (key to document store) subcomponent see: https://docs.yugabyte.com/latest/architecture/concepts/persistence/ |
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@shreklei : Closing the issue; hopefully the above comment answers the questions you asked. |
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If a DocDB serves a Tablet, then a node with 1000 or 10000 Tablets is not a strange phenomenon, does it mean that there will be 1000 or 10000 DocDB instances? If so, it will be a disaster for memory and CPU resources. |
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@shreklei - the number of tablets being this high should not be a very common phenomenon. Unless you have have 100s or 1000s of tables. You can also control the initial number of tablets a table is created with, and there isn't much advantage of setting this number so high that you end up with 1000s of tablets per node. Each YugaByte tablet can get pretty big. Another reason you don't want too many tablets is because each tablet has its own RAFT group, and 10000s of RAFT groups add overhead-- and again, you don't gain much by micro-splitting your tables into too many small tablets. Having said that, YugaByte does keep the overhead of each tablet very low. Resources such as block cache, compaction threads, total memstore resources etc. are shared across all the DocDB instances. Read more here: https://docs.yugabyte.com/latest/architecture/concepts/persistence/. Copy pasting a few relevant points:
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Can you add more drives to the docker image or does it need to be redone? |
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cc: @rkarthik007 , @Arnav15, @ramkumarvs -- is the number of data drives presented to the yb-tserver or yb-master pods already configurable in the Kubernetes based install? |
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@dlessner - yes the number of disks are configurable. You have to manually edit the yaml files, but I can add instructions if you can use our helm chart. We have tested creating clusters from 1 to 5 disks of varying sizes attached (of course the underlying IaaS should be able to support the sizes for the pv). As far as changing this on the fly - I think you might be able to "patch" the attribute, but most likely kubernetes will redeploy all pods. Not sure about that one, need to try and get back. |
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fix dbms_output.serveroutput(true) clear the buffer.
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…ith-main PG-364 Aligned docs structure with main
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When an internal function already returns a type name with double quotes, doesn't add another one. Fix yugabyte#200
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Summary: Copyright update. Initial commit. The plugin was first named json_decoding_plugin but changed the name after discussion on -hackers. It is a POC to illustrate that it is possible for changeset extraction work just fine. The changeset extraction feature is already in development, hence, it is expected that this code changes a lot until the feature is set in stone. It is based on: repository: git://git.postgresql.org/git/users/andresfreund/postgres.git branch: xlog-decoding-rebasing-remapping commit: 6f819a68cd10938df126ee44a3cfef7f457c8e1b Generate a long bytea instead of explicitly writing a long one. It reduces the sql file size. Suggested by Merlin Moncure. In commit ea177a3ba7a7901f6467eadb0a407e03d46462fd, the internal structure was changed. Unbreak regression tests. Remove contrib dependency. The old Makefile relies heavily on been in the contrib tree. While analysing the ethansf pull request, I realized that that premise does not hold water because you could build it without a source code tree. Although I didn't have used his patch [1], this code was inspired on it. [1] eulerto/wal2json#1 Fix regression tests. The regression tests was very unstable. The main reason is the associated LSN in some CONTEXT messages. Adding VERBOSITY setting to supress those CONTEXT messages. Update copyright. Include LSN position for the next transaction. This feature was discussed with @ethansf and is useful for tool that consumes WAL using pg_recvlogical and similar tools. The LSN is important to mark the apply progress. It stores the LSN pointing to the end of commit record + 1. Hence, if the consuming tool crashes while applying a transaction (JSON document), it can restart the pg_recvlogical streaming from the last saved LSN position. This is essential for such consuming tool to work properly. Although, I did not have used Ethans' patch, this piece of code is based on his idea. Rename "next lsn" JSON key. It is a comestic change because you can access values like: foo['next lsn'] The other form (foo.bar) is not possible because of the blank space. Fix handling of nonexistant columns in old tuple versions. This fix was discoverd in bug yugabyte#13470 and commit d47a1136e441cebe7ae7fe72d70eb8ce278d5cd6 fixes it. pretty print option. The new parameter 'pretty-print' chooses between a compact (without spaces) or a pretty-print format. The default changed to compact format since tools usually transform the JSON objects. Control how the stream is written. The new parameter 'write-in-chunks' controls how to write in the stream. If true, write occurs per tuple; else it writes at the end of transaction. The default is true. Hence, the behavior is the same as prior code. Add a real README. README has instructions to build and install wal2json. Also, there are examples of use. Add Coverity Scan Badge Replace palloc with palloc0 Avoid garbage on JsonDecodingData. Fixed tests results Give an error instead of a warning in case of bad param Added gitignore Ignore .o files Error message on unknown params reworded Merge pull request yugabyte#13 from dvarrazzo/gitignore Added gitignore Merge pull request yugabyte#12 from dvarrazzo/err-on-bad-option Give an error instead of a warning in case of bad param Merge pull request yugabyte#11 from dvarrazzo/fix-tests Fixed tests results Default for write-in-chunks changed to false Default for include-xids changed to false style fix Update copyright year information Dropped include-xids=0 from test suite Avoid leaking memory when we have some can-not-happen situations Fix LICENSE Forgot to replace organization. Merge pull request yugabyte#18 from dvarrazzo/better-defaults Better defaults Use '1' and '0' instead of 't' and 'f' on tests Forgot to add some static on functions Daniele Varrazzo Support generic WAL messages for logical decoding This feature allows software to insert data into WAL stream that can be read by wal2json. Those messages could be useful to control replication, for example. Messages can be sent as transactional or not. Non-transactional messages mean that it is sent even if the transaction is rollbacked. There was a PR yugabyte#20 for this same feature but I didn't use it. Indeed, this code was dusty in my computer for a few months. NOTE: 'message' test will fail on <= 9.5 because this feature was coded in 9.6 (I don't want to complicate Makefile). Fix generic WAL messages As spotted in issue yugabyte#28, I committed a code that was not supposed to be part of the original commit 645ab69. Thanks to Julien Rouhaud (@rjuju) to bring it up. Support type name with modifier Issue yugabyte#31 asked for type name with type modifier (if available). This commit implemented type modifier inclusion by default. It is possible to use the old type name, if you use the option 'include-typmod' as 'false'. I'll change the regression tests to use the new format later. I've added a new test (typmod) to exercise this new option. Fix a description Remove superfluous includes rel.h includes pg_class.h, index.h, and relcache.h. logical.h includes output_plugin.h. All of the others are not necessary. TupleDescAttr() support Commit d34a74dd064af959acd9040446925d9d53dff15b introduced TupleDescAttr(tupdesc, i) in back branches (9.4.14, 9.5.9, 9.6.5, 10). If the version supports it, use this macro. This change will unbreak (future) version 11. Support type oids Issue yugabyte#37 asked for type oids in the output because psycopg2 uses it directly for internal type manipulation. Although @lionel-panhaleux had provided PR yugabyte#38, I didn't like the way it was implemented mainly because it mixes options. The new option 'include-type-oids' has default to false. I didn't provide tests for this feature. Support not-null constraints information Issue yugabyte#44 asked for not-null constraints information because the other side could benefit from this. The new option 'include-not-null' will add another name/value pair (columnoptionals) that contains false for not-null constraint (it means that the value is not optional) or true, otherwise. The default is false. Improve JSON encoding: * use the postgres builtin escape_json() function * escape all type, schema, table, field names. Add tests. [yugabyte#35] * leave `\x` alone unless it's a bytea prefix [yugabyte#23] * escape generic logical decoding messages with tests Update call to AllocSetContextCreate for PostgreSQL 9.6+ Merge pull request yugabyte#55 from davidfetter/pg_96_plus Update call to AllocSetContextCreate for PostgreSQL 9.6+ Filter out tables The new parameter 'filter-tables' is a comma separated value that contains schema.table elements. Both schema and table can be * that denotes all. Hence, *.table_1 means table_1 in all schemas and schema_1.* means all tables in schema_1. Some characters (space, single quote, comma, period, asterisk) have special treatment because they are part of the comma separated value. If any of these characters is part of the schema or table name, add a backslash (\) before it. For example, table public."foo bar" should be specified as 'public.foo\ bar'. Select tables to retrieve data The new parameter 'add-tables' select only data from those tables. Like parameter 'filter-tables', it is a comma separated value that contains schema.table elements. Both schema and table can be * that denotes all. Escape also works for special characters. By default, all tables in all schemas are selected. Merge pull request yugabyte#40 from koordinates/encoding Improve JSON encoding Preserve unchanged toast values by default. Use `include-unchanged-toast=0` option to suppress. Merge pull request yugabyte#50 from koordinates/include-unchanged-toast Preserve unchanged toast values by default. This commit introduces a behavior change since TOAST values will always be output from now on. If you want the previous behavior, add include-unchanged-toast=0. Style fixes for last commit Copyright update Document parameters Update examples The examples don't reflect the defaults options. Also, rename tables in SQL functions example (avoid table conflict with the other test). Build wal2json out of the tree on Windows Build out of the tree is a common task in Unix-like systems (PostgreSQL has PGXS but it doesn't support Windows). This commit adds a project file to build out of the tree on Windows. I also add minimal instructions to build on Windows. I tested wal2json on MS Visual Studio 2017 (version 15.6.4) on a x64 platform. Improve style Fix oversight in copyright message LICENSE is correct but C file has wrong copyright message. Tweak message test Per PR yugabyte#59, replace bytea value with valid data. Sanity checks after selective table options The sanity checks should be run after filter-tables and add-tables options to avoid a bunch of unsolicited warnings (per issue yugabyte#64). Refactor wal2json output Almost all writes were handled in two different ways: with or without pretty print. It means more lines of code and an error-prone code. The new code avoids all of the pretty-print tests and also uses only one setence per output. It reduces the code by more than 150 lines. I also fix some comments (use only C89 comments) and improve style. Revert include-unchanged-toast option Per discussion in issue yugabyte#74, we can't rely on access unchanged TOAST data because it is not in the WAL stream. It reverts commits 947043e ce82d73 and d86a13b . Add an error message to include-unchanged-toast parameter Per issue yugabyte#74, parameter include-unchanged-toast wasn't safe, hence, remove it. Since it is part of release 1.0, deprecate this option for the next release. Make wal2json logging less chatty Suppress the "XXX argument is null" message. Decrease the TOAST message level from WARNING to DEBUG1. Also, decrease some debug message levels. Improve perf on deletes when repl ident full Merge pull request yugabyte#82 from rkrage/repl-ident-full-perf Improve perf on deletes when repl ident full Add tests for include-timestamp option Add tests for include-lsn option Add tests for include-xids option Merge pull request yugabyte#94 from paulczajka/add-tests Add tests for timestamp, lsn, xids options Avoid null pointer dereference with empty filter-tables As spotted by clang: wal2json.c:321:21: warning: Dereference of null pointer rawstr = pstrdup(strVal(elem->arg)); ^~~~~~~~~~~~~~~~~ /usr/include/postgresql/11/server/nodes/value.h:54:20: note: expanded from macro 'strVal' Add option format-version This option defines which format to use. Only version 1 is currently supported. New formats will be available. Note include-unchanged-toast is deprecated Merge pull request yugabyte#102 from benjie/patch-1 Note `include-unchanged-toast` is deprecated Merge pull request yugabyte#97 from xrmx/nullfiltertables Avoid null pointer dereference with empty filter-tables remove empty line Add 'cd' command to README Merge pull request yugabyte#107 from benjie/patch-2 Add 'cd' command to README PATH should contain the parent folder of pg_config Merge pull request yugabyte#108 from benjie/patch-3 PATH should contain the parent folder of pg_config Fix add-tables to filter single-character schemas Add extra_float_digits to tests Postgres commit 02ddd499322ab6f2f0d58692955dc9633c2150fc for v12 and later, changes the default number of trailing digits output for double precision. Add extra_float_digits to keep regression tests stable. Filter messages by prefix The new parameter 'filter-msg-prefixes' filters messages with those prefixes. It a comma separated value. By default no messages are filtered. Per off-list discussion with @martinmarques Updated copyright to 2019 Add messages by prefix The new parameter 'add-msg-prefixes' adds only messages with these prefixes. It is a comma separated value. By default all messages are included. wal2json enforces this rule after 'filter-msg-prefixes'. Per off-list discussion with @martinmarques Merge pull request yugabyte#123 from davidfetter/copyright_2019 Updated copyright to 2019 Update instructions Since version 10, we don't need to adjust parameters. Also, pg_hba.conf changes its behavior. It matches normal connections instead of (physical) replication connections. Merge pull request yugabyte#113 from benjie/patch-4 Fix add-tables to filter single-character schemas New wal2json format This is a new format for wal2json. You can choose it using option 'format-version' = 2. This format is completely different from version 1. Features are: * one JSON per tuple; * each JSON has an "action" (BEGIN, COMMIT, INSERT, UPDATE, DELETE, MESSAGE); * one (optional) JSON object for BEGIN/COMMIT; * BEGIN contains xid, timestamp, and lsn; * COMMIT contains xid, timestamp, and lsn; * INSERT/UPDATE/DELETE contains lsn, schema, table, columns, identity; * "columns" and "identity" are arrays of elements; * each "columns" element is an object that contains name, type, value, and optional; * "identity" is an array of elements (REPLICA IDENTITY for UPDATE / DELETE statements) that contains name, type, and value; * MESSAGE contains xid, timestamp, lsn, transactional, prefix, and content. This new format solves the big transaction issue (that consumes a lot of memory) since tuples aren't accumulate until the end of transaction to be written. Users can control transactions using option include-transaction that will emit a JSON at the beginning of the transaction and another one at the end of the transaction. Fix tests Postgres 12 breaks random() predictability. Since we use the same tests for all versions, replace random() with a sequence. Improve regression test message regression test used to fail with 9.4 and 9.5. That's because message API is available in 9.6 and later. Filter out this test if the major version is 9.4 or 9.5. Add parameter include-origin This parameter includes replication origin. Default is false. Format version 2 adds origin information in BEGIN, COMMIT, CHANGE, and MESSAGE. In format version 1, origin is also available. Since replication origin was introduced in 9.5, 9.4 does not print origin information. Support TRUNCATE command for logical decoding This feature includes TRUNCATE commands into wal2json output. It was introduced in PostgreSQL 11 which means that wal2json will support it only for this version and on. Format version 2 will output it by default. Format version 1 won't (maintain backward compatibility). (A new option will be added to select actions -- insert, update, delete, truncate -- and it should be possible to output TRUNCATE commands in version 1 too). Option actions This new feature let users select actions they want to receive. Actions supported are insert, update, delete, and truncate. This actions are similar to PUBLICATION command. Format version 1 won't enable truncate by default (to maintain backward compatibility). Format version 2 will enable all options by default. A new test was added (run only on Postgres v11 or later). That's because test includes truncate and it will only supported by v11 or later. Adjust default format version Format version 1 will still remain the default version. wal2json does not require a format version until a few commits ago (with no new version released) and use a new format version will break calls that does not inform format-version parameter. Let's give some time to users adopt format-version parameter. format-version 2 example This new example shows the output for format-version 2. Fix license oversight The wal2json license is BSD 3-clause, however, there is a sentence in the README that says it is released under PostgreSQL license (it is not). This is an oversight in the commit 0b653ee. Update copyright Adjust instructions Use default max_replication_slots value as suggestion for examples / tests. Fix oversight in option actions This oversight was introduced in commit aa431a9. Issue yugabyte#148 reported by @dko-slapdash. Fix memory leak while using add-tables and filter-tables This issue was reported in PR yugabyte#147 by @haizz. The proposed fix was incomplete (as I pointed out) and I fixed add-tables option and also format 2 (add-tables and filter-tables). Fix segfault on 32 bits I forgot to pass a Datum and I'm surprised it haven't crashed yet. This commit fixes issue yugabyte#142. Reported by @df7cb and confirmed by @cpaelzer. Use correct format specifier uint64 should use UINT64_FORMAT instead of %lu because format specifier depends on a type probe. It suppresses a compiler warning. Move some debug code for general function Some debug messages were only printed if we are using format 1, let's move them to general function. Add macro for backward compatibility UInt64GetDatum was introduced in 9.6. I forgot to test old stable versions and didn't get it. Fortunately, @df7cb reported it. Add parameter include-domain-data-type This parameter replaces domain name with its underlying data type. Default is false (backward compatibility). Both formats (1 and 2) are supported. It is useful if you want to expose the "real" data type. struct ReorderBufferTXN changed Some struct members (including has_catalog_changes) was turned into a single variable since v13 (cf postgres commit a7b6ab5db1d35438112f74f3531354ddd61970b5). Rephrase include-unchanged-toast docs This parameter was deprecated some time ago. However, its description is confusing users. Let's add a blink alert to NOT use it. It will eventually be removed. Add expected file for parameter include-domain-data-type Commit e33df94 forgot to add expected file. Add parameter filter-origins This parameter is useful in multidirectional replication solutions. It can prevent replicating some data back and forth. Although, each transaction has origin information, filter using this callback is more efficient. This callback is available in 9.5+. Improve Linux installation instructions Since there are some issues that are opened from time to time, I add a few instructions to Linux distros. I add instructions to install the available packages from Debian/Ubuntu and RHEL/CentOS. I also write some instructions to compile on those OSes. I hope it should clarify doubts about installation. Fix an oversight for old minor versions Format 2 (1b0cbac) forgot to consider the workaround I applied to TupleDescAttr (5352cc4). Since I did not test with old minor versions, this bug was not caught by tests. This was reported in issue yugabyte#162. Improve configuration section Add a comment explaining which parameters need adjust based on the version users are using. Version 10 or later just need to change wal_level, for example. Though, old versions have to adjust a few parameters to use logical replication. Add parameter include-column-positions This parameter is useful to detect schema changes (since attnum are numbered from 1 up). Both formats (1 and 2) are supported although element names are different ("columnpositions" for format 1 and "position" for format 2). Default is false. Issue yugabyte#160 Add parameter include-default This parameter adds "columndefaults" that contains all defaults values (same as pg_get_expr). Both formats (1 and 2) are supported although element names are different ("columndefaults" for format 1 and "default" for format 2). Each default value is represented as string because it can be an expression. Tests are included. Default is false. I also added prototypes to 2 static functions. Add parameter include-pk This parameter adds primary key information if it is available. Both formats (1 and 2) are supported. Each "pk" object provides column name and its data type. Tests are included. Default is false. Fix an oversight in format 2: nextlsn Format 2 (1b0cbac) forgot to add nextlsn. Format 1 includes this information if include-lsn is provided. This information can be useful for applications that use LSN position as a restart point. Fix package name As pointed by @MaxmaxmaximusAWS Debian/Ubuntu package name was wrong. It fixes yugabyte#175. Update instructions to Postgres 13 Since Postgres 13 was released a few days ago, let's update wal2json instructions. I also replaced wal2json version with the latest version (2.3). Improve pretty print Replace strcpy() and strncpy() with an assignment. Improve documentation Add 'message' usage to the examples. In comparison to the widely used output plugins such as pgoutput and pglogical 2, wal2json is the only plugin that supports message_cb. Fix table names in the example I renamed the tables in the first example but forgot to change the script. Remove unused code Don't rely on index attribute names for primary key If you rename a column that is part of the primary key, the attname for the primary key index isn't renamed. Someone could argue that it is a Postgres bug (I think it is a catalog inconsistency that could probably be fixed eventually) but it seems the cure is worse than the disease (see [1]). The code was refactored to avoid comparison by attribute name, instead it uses RelationGetIndexAttrBitmap() that obtains a bitmap of index attribute numbers based on its kind (primary key, identity, ...). Closes yugabyte#11 [1] https://www.postgresql.org/message-id/CAA8M49r%3D1XoE27tQ08sAPhft_ayBu4Vvib%2BubwX4SRqtUGJ%2B3g%40mail.gmail.com Combine common code into functions Instead of repeating code into different wal2json format output functions, combine the common code into functions and use them. Add docs on include-origin option. document include-transaction option Filter is not applied for TRUNCATE Filter is failing to exclude tables that matchs the filter. Filter code was refactored at commit a96dd31 but I forgot to replace the filter in the truncate function. I include a regression test to cover this code. Merge pull request yugabyte#207 from olirice/master Document include-transaction option Avoid duplicate double quotes for type names When an internal function already returns a type name with double quotes, doesn't add another one. Fix yugabyte#200 Stamp 2.4 default value was not always printed in v1 This bug prevents a default value to be printed in v1 after a TRUNCATE statement. Reported by @ls-guillaume-rebesche Fixes yugabyte#225 Parameter write-in-chunks is only used for format version 1 If you set format-version to 2, parameter write-in-chunks has no effect. Document this behavior. Fixes yugabyte#228 Add Postgres 14 to the installation instructions Refer to the latest Postgres version in the instructions. Update copyright year Add include-type-oids support in format-version 2 unbreak test on old versions 'default' test uses TRUNCATE that is not supported in v10 and previous versions. Add an alternate test file to cover this case. Array type does not print the correct type name If the base type requires quotes and the type is an array, wal2json is not quoting the whole type name. Instead, it was not considering the brackets as part of the type name. Fix both format versions. Fixes yugabyte#233 Lag tracking support See lag times in pg_stat_replication. Add PostgreSQL 15 support Merge pull request yugabyte#247 from Naros/postgres15-compatibility Add PostgreSQL 15 support Stamp 2.5 Add option to output numeric data types as string. (yugabyte#255) Add option to output numeric data types as string. Data types like `numeric`, `real`, `double precision` supports `Infinity`, `-Infinity` and `NaN` values. Currently these values output as `null` because JSON specification does not recognize them as valid numeric values. This will create problems for the users of wal2json who need these values to maintain data integerity. invalid JSON for non-transaction message in v1 (yugabyte#266) Non-transactional messages contain only one object. It means comma should not be provided for such JSON objects. If you are sending a non-transactional message into a transaction, it should guarantee that comma is only emitted for transactional commands. Hence, the previous check is weak and it should also check for transactional information. Fixes yugabyte#266 Correct DELETED tuple reference pg_decode_change_v1 (yugabyte#252) Avoid variable shadowing Fix typo Fix lag tracking support for large transactions Postgres fixed some time ago a logical replication timeout during large transactions (commit postgres/postgres@f95d53e). For Postgres 16, a proper fix was added in the logical decoding but the previous versions (10 to 14) a new function (update-replication_progress) was added. It is the same function used by pgoutput plugin. Fixes yugabyte#270 Add version Packages might rely on the version from source code instead of extracting the version from the tarball file name. If the WAL2JSON_VERSION contains "dev" suffix it means it is not a released version. WAL2JSON_VERSION_NUM changes only for release. After a release, the next commit will add the "dev" suffix that will be removed only for the next release. Replace tab with space Update .gitignore Fix include-pk when replica identity is full In format 1, the primary key information was not included even though the include-pk option is enabled. It happens when the table has a primary key and the replica identity is full. Format 2 was not affected. Fixes yugabyte#273 Update instructions with the latest PostgreSQL version wal2json supports up to the latest supported version: 16. Fix Red Hat package name Update copyright year Add PostgreSQL 17 support Postgres 17 changed the ReorderBufferChange data structure (commit postgres/postgres@08e6344). Update build infrastructure for Windows It updates MS Visual Studio from 2017 (v141) to 2022 (v143). It also changes the target OS from 8.1 to 10.0 because Windows 8 was EOL for some time (Windows 10 is also deprecated 3 months ago but since it is the one I used to test these builds, I kept it. Feel free to update WindowsTargetPlatformVersion if you are using a newer Windows version.) It also includes a solution file (wal2json.sln -- although there aren't multiple project files) that you can also use to trigger the build using the following command: msbuild wal2json.sln /verbosity:normal /p:Configuration=Release I tested these builds with Postgres 10 and later on x86_64. Stamp 2.6 Add 'src/postgres/third-party-extensions/wal2json/' from commit '75629c2e1e81a12350cc9d63782fc53252185d8d' git-subtree-dir: src/postgres/third-party-extensions/wal2json git-subtree-mainline: 66ed3a5 git-subtree-split: 75629c2 Test Plan: jenkins: compile only Subscribers: yql Differential Revision: https://phorge.dev.yugabyte.com/D36690
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