pgloader had support for PostgreSQL SET parameters (gucs) from the
beginning, and in the same vein it might be necessary to tweak MySQL
connection parameters, and allow pgloader users to control them.
See #337 and #420 where net_read_timeout and net_write_timeout might need to
be set in order to be able to complete the migration, due to high volumes of
data being processed.
This pgloader command allows to migrate tables while changing the schema
they are found into in between their MySQL source database and their
PostgreSQL target database.
This changes the default behavior of pgloader with MySQL from always
targetting the 'public' schema to targetting by default a schema named
the same as the MySQL database. You can revert to the old behavior by
adding a rule:
ALTER SCHEMA 'dbname' RENAME TO 'public
We might want to add a patch to re-install the default behavior later.
Also see #489 where it used not to be possible to rename the schema at
migration time, causing strange errors (you need to spot NIL as the
schema name in the "failed to find target table" messages.
By default, pgloader will start as many parallel CREATE INDEX commands
as the maximum number of indexes you have on any single table that takes
part in the load.
As this number might be so great as to exhaust the target PostgreSQL
server (e.g. maintenance_work_mem), we add an option to limit that to
something reasonnable when the source schema isn't.
Fix#386 in which 150 indexes are found on a single source table.
The new ALTER TABLE facility allows to act on tables found in the MySQL
database before the migration happens. In this patch the only provided
actions are RENAME TO and SET SCHEMA, which fixes#224.
In order to be able to provide the same option for MS SQL users, we will
have to make it work at the SCHEMA level (ALTER SCHEMA ... RENAME TO
...) and modify the internal schema-struct so that the schema slot of
our table instances are a schema instance rather than its name.
Lacking MS SQL test database and instance, the facility is not yet
provided for that source type.
Add the workers and concurrency settings to the LOAD commands for
database sources so that users can tweak them now, and add mentions of
them in the documentation too.
From the documentation string of the copy-from method as found in
src/sources/common/methods.lisp:
We allow WORKER-COUNT simultaneous workers to be active at the same time
in the context of this COPY object. A single unit of work consist of
several kinds of workers:
- a reader getting raw data from the COPY source with `map-rows',
- N transformers preparing raw data for PostgreSQL COPY protocol,
- N writers sending the data down to PostgreSQL.
The N here is setup to the CONCURRENCY parameter: with a CONCURRENCY of
2, we start (+ 1 2 2) = 5 concurrent tasks, with a CONCURRENCY of 4 we
start (+ 1 4 4) = 9 concurrent tasks, of which only WORKER-COUNT may be
active simultaneously.
Those options should find their way in the remaining sources, that's for
a follow-up patch tho.
In order to share more code in between the different source types,
finally have a go at the quite horrible mess of anonymous data
structures floating around.
Having a catalog and schema instances not only allows for code cleanup,
but will also allow to implement some bug fixes and wishlist items such
as mapping tables from a schema to another one.
Also, supporting database sources having a notion of "schema" (in
between "catalog" and "table") should get easier, including getting
on-par with MySQL in the MS SQL support (materialized views has been
asked for already).
See #320, #316, #224 for references and a notion of progress being made.
In passing, also clean up the copy-databases methods for database source
types, so that they all use a fetch-metadata generic function and a
prepare-pgsql-database and a complete-pgsql-database generic function.
Actually, a single method does the job here.
The responsibility of introspecting the source to populate the internal
catalog/schema representation is now held by the fetch-metadata generic
function, which in turn will call the specialized versions of
list-all-columns and friends implementations. Once the catalog has been
fetched, an explicit CAST call is then needed before we can continue.
Finally, the fields/columns/transforms slots in the copy objects are
still being used by the operative code, so the internal catalog
representation is only used up to starting the data copy step, where the
copy class instances are then all that's used.
This might be refactored again in a follow-up patch.
In order to later be able to have more worker threads sharing the
load (multiple readers and/or writers, maybe more specialized threads
too), have all the stats be managed centrally by a single thread. We
already have a "monitor" thread that get passed log messages so that the
output buffer is not subject to race conditions, extend its use to also
deal with statistics messages.
In the current code, we send a message each time we read a row. In some
future commits we should probably reduce the messaging here to something
like one message per batch in the common case.
Also, as a nice side effect of the code simplification and refactoring
this fixes#283 wherein the before/after sections of individual CSV
files within an ARCHIVE command where not counted in the reporting.
The dry run option will currently only check database connections, but
as that happens after having correctly parsed the load file, it allows
to also check that the command file is correct for the parser.
Note that the list load-data API isn't subject to the dry-run method.
In passing, we add some more API entry points to the connection objects
and we should actually clean the code base to use the new QUERY generic
all over the place. It's for another patch tho.
pgloader used to have a single database name parsing rule that is
supposed to be compliant with PostgreSQL identifier rules. Of course it
turns out that MySQL naming rules are different, so adjust the parser so
that the following connection string is accepted:
mysql://root@localhost/3scale_system_development
That's the big refactoring patch I've been sitting on for too long.
First, refactor connection handling to use a uniformed "connection"
concept (class and generic functions API) everywhere, so that the COPY
derived objects just use that in their :source-db and :target-db slots.
Given that, we don't need no messing around with *pgconn* and *myconn-*
and other special variables at all anywhere in the tree.
Second, clean up some oddities accumulated over time, where some parts
of the code didn't get the memo when new API got into place.
Third, fix any other oddity or missing part found while doing those
first two activities, it was long overdue anyway...
Make it so that the following command line usages are accepted when
using pgloader without a command file:
./build/bin/pgloader ./test/sqlite/sqlite.db postgresql:///pgloader
./build/bin/pgloader --set "search_path='sakila'" \
mysql://root@localhost/sakila \
postgresql:///sakila
./build/bin/pgloader --type csv \
--field id --field field \
--with truncate \
--with "fields terminated by ','" \
./test/data/matching-1.csv \
postgres:///pgloader?matching
It's now possible in most cases to just use command-line options, which
should make the entry bar to pgloader much lower.
Now it's possible to parse a command to load data from MS SQL. The
parser was until now parsing all database URI within the same common
rule and that isn't possible anymore if we want to distinguish in
between source database right from the parser, which we actually want to
do.
This patch also implement in-passing fixes all over the place, including
the transformation function float-to-string that only happened to work
on double-float data.
